DOT HS 812 014 August 2014

Vehicle-to-Vehicle Communications: 

Readiness of V2V Technology for 

Application
DISCLAIMER

This publication is distributed by the U.S. Department of Transportation, National 

Highway Traffic Safety Administration, in the interest of information exchange. 

The opinions, findings, and conclusions expressed in this publication are those of 

the authors and not necessarily those of the Department of Transportation or the 

National Highway Traffic Safety Administration. The United States Government 

assumes no liability for its contents or use thereof. If trade or manufacturers’ names 

or products are mentioned, it is because they are considered essential to the object 

of the publication and should not be construed as an endorsement. The United 

States Government does not endorse products or manufacturers.

Suggested APA Format Citation:

Harding, J., Powell, G., R., Yoon, R., Fikentscher, J., Doyle, C., Sade, D., 

Lukuc, M., Simons, J., & Wang, J. (2014, August). Vehicle-to-vehicle 

communications: Readiness of V2V technology for application. (Report 

No. DOT HS 812 014). Washington, DC: National Highway Traffic Safety 

Administration.
i 

Technical Report Documentation Page 

1. Report No. 2. Government Accession No. 3. Recipient’s Catalog No. 

DOT HS 812 014 

4. Title and Subtitle 5. Report Date 

Vehicle-to-Vehicle Communications: Readiness of V2V Technology 

for Application 

August 2014 

6. Performing Organization Code 

7. Authors 8. Performing Organization 

Report No. 

John Harding, Gregory Powell, Rebecca Yoon, Joshua Fikentscher, Charlene 

Doyle, Dana Sade, Mike Lukuc, Jim Simons and Jing Wang 

9. Performing Organization Name and Address 10. Work Unit No. (TRAIS) 

National Highway Traffic Safety Administration 

1200 New Jersey Avenue SE. 

Washington, DC 20590 

11. Contract or Grant No. 

12. Sponsoring Agency Name and Address 13. Type of Report and Period 

Covered 

Research 

14. Sponsoring Agency Code 

15. Supplementary Notes 

16. Abstract 

The purpose of this research report is to assess the readiness for application of vehicle-to-vehicle (V2V) 

communications, a system designed to transmit basic safety information between vehicles to facilitate warnings to 

drivers concerning impending crashes. The United States Department of Transportation and NHTSA have been 

conducting research on this technology for more than a decade. This report explores technical, legal, and policy 

issues relevant to V2V, analyzing the research conducted thus far, the technological solutions available for 

addressing the safety problems identified by the agency, the policy implications of those technological solutions, 

legal authority and legal issues such as liability and privacy. Using this report and other available information, 

decision-makers will determine how to proceed with additional activities involving vehicle-to-vehicle (V2V), 

vehicle-to-infrastructure (V2I), and vehicle-to-pedestrian (V2P) technologies. 

17. Key Words 18. Distribution Statement 

vehicle-to-vehicle communications, crash avoidance, connected vehicle, safety 

applications, model deployment, safety pilot, vehicle awareness device, 

integrated device, aftermarket safety device, communication security, security 

credential management system, V2V technology 

Document is 

available to the 

public from the 

National Technical 

Information Service 

www.ntis.gov 

19 Security Classif. (of this report) 20. Security Classif. (of this page) 21 No. of 

Pages 

327

22. Price 

Unclassified Unclassified 

Form DOT F 1700.7 (8-72) Reproduction of completed page authorized
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Table of Contents

I. Executive Summary ...........................................................................................................................xiii

II. Introduction...........................................................................................................................................1

A. Purpose of this report........................................................................................................................1

B. History of V2V communication research program...........................................................................3

1. History of ITS ...............................................................................................................................3

2. History of V2V research program and its role in ITS...................................................................4

3. The Connected Vehicle Safety Pilot Program ..............................................................................8

4. Studies related to V2V light-vehicle research.............................................................................10

5. Vehicle-to-infrastructure (V2I)...................................................................................................11

III. Safety Need.....................................................................................................................................15

A. Crashes potentially addressed by V2V technology.........................................................................16

B. Potential for V2V to address vehicle crashes..................................................................................24

C. Ways of addressing the safety need ................................................................................................25

1. Scenarios addressed uniquely by vehicle-to-vehicle communications.......................................25

2. Scenarios also addressed by vehicle sensor-based systems........................................................27

3. Scenarios possibly addressed by a combination of vehicle resident sensors and V2V 

communications.............................................................................................................................28

D. Types of V2V devices.....................................................................................................................29

1. OEM devices...............................................................................................................................29

2. Aftermarket devices....................................................................................................................29

3. Infrastructure-based devices .......................................................................................................32

IV. Scope and Legal Authority .............................................................................................................33

A. NHTSA’s scope and legal authority and how it applies to vehicle to vehicle communication ......33

1. Integrated OEM V2V technologies.............................................................................................36

2. Integrated aftermarket equipment ...............................................................................................37

3. Non-integrated aftermarket equipment .......................................................................................38

4. Software that aids or updates the V2V system............................................................................40

5. Roadside infrastructure (V2I) .....................................................................................................41

B. Agency actions that are practicable and consistent with its legal authority....................................45
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1. Elements of the Safety Act that would apply to potential future agency actions........................45

2. Safety standards for DSRC.........................................................................................................54

3. Safety standards for DSRC-enabled safety applications.............................................................59

4. Discussion of need for additional legal authority prior to taking regulatory actions regarding 

vehicle to vehicle communication .................................................................................................62

C. Non-regulatory actions required to stand up V2V communications...............................................62

D. Authority for the spectrum in which V2V will operate, and how it could affect the development of 

a V2V system..................................................................................................................................63

V. Technical Practicability.......................................................................................................................65

A. Technical practicability and its importance to an agency decision.................................................65

B. Overview of hardware components enabling system operation......................................................65

1. Components used in testing ........................................................................................................66

2. Components required for V2V system operation........................................................................67

3. Vehicle-based hardware..............................................................................................................67

4. Non-vehicle-based hardware.......................................................................................................69

C. Overview of software enabling system operation...........................................................................70

D. Interoperability................................................................................................................................71

1. Interoperability and its importance .............................................................................................71

2. Current maturity level of V2V wireless communication channels.............................................87

3. Interoperability performance requirements.................................................................................96

E. System Limitations .......................................................................................................................105

1. What are the known system limitations for V2V communication? ..........................................105

2. Potential mitigation strategies for known system limitations...................................................112

3. Device installation constraints and requirements......................................................................114

4. Managing device updates and improvements...........................................................................115

F. Global activities and differences in V2V systems ........................................................................116

1. Research and/or implementation of V2V communications in other regions............................116

2. Differences between the current U.S. regional vision and other regions..................................116

VI. V2V Safety Applications..............................................................................................................119

A. Performance metrics currently available for V2V safety applications .........................................119

B. The safety applications..................................................................................................................120

C. Key Findings for each V2V Safety Application ...........................................................................121

1. Forward Collision Warning ......................................................................................................121

2. Emergency Electronic Brake Lights.........................................................................................122
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3. Do Not Pass Warning................................................................................................................122

4. Left Turn Assist ........................................................................................................................122

5. Intersection Movement Assist...................................................................................................123

6. Blind Spot + Lane Change Warning.........................................................................................123

D. Key conclusions for each application ...........................................................................................124

1. Forward Collision Warning ......................................................................................................124

2. Blind Spot Warning + Lane Change Warning..........................................................................124

3. Do Not Pass Warning................................................................................................................124

4. Left Turn Assist ........................................................................................................................125

5. Emergency Electronic Brake Light...........................................................................................126

6. Intersection Movement Assist...................................................................................................126

7. False warning improvement research .......................................................................................126

8. Performance measures improvement research..........................................................................127

E. Driver-vehicle interface ................................................................................................................129

F. Summary of major recommendations concerning safety applications..........................................130

G. System compliance and enforcement............................................................................................130

VII. Public Acceptance.........................................................................................................................133

A. The importance of public acceptance............................................................................................133

1. Potential key aspects of consumer acceptance for V2V communication..................................133

2. Potential issues with industry support for V2V communication systems.................................136

3. Preliminary information on consumer acceptance....................................................................137

VIII. Privacy Considerations .................................................................................................................144

A. Privacy considerations – what they are and why they are important............................................144

1. Transmission, collection, storage, and sharing of V2V data.....................................................145

2. Privacy policies framework ......................................................................................................146

3. The fair information practice principles....................................................................................148

B. NHTSA’s interim privacy risk assessment ...................................................................................150

1. V2V system needs/functions that necessitate data transactions posing potential risks 

to privacy .....................................................................................................................................153

2. Potential risks to privacy introduced by V2V communications or other data transactions necessary 

to satisfy system need ..................................................................................................................154

3. Technical, physical and/or policy controls evaluated to minimize potential privacy risks..........155

4. Significance of the identified potential privacy risks...................................................................156

IX. V2V Communications Security ....................................................................................................158
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A. Overview and importance of security ...........................................................................................158

1. Security options considered ......................................................................................................159

2. Overview of PKI and how it works ..........................................................................................163

3. Limitations of existing PKI systems.........................................................................................165

B. Current V2V security design concept ...........................................................................................165

1. SCMS component functions .....................................................................................................168

2. Pseudonym functions/certificates .............................................................................................168

3. Initialization functions/enrollment certificate...........................................................................171

4. Comparing a basic PKI to the V2V security design .................................................................174

5. V2V security research conducted or underway ........................................................................177

6. Overall application of cryptography in V2V communications.................................................179

7. Additional information on the current V2V security system design and research....................182

C. Overview of system integrity and management............................................................................184

1. Key elements of system integrity and management..................................................................186

2. SCMS ownership and operation ...............................................................................................193

3. “Enforcement” of system integrity/SCMS manager.................................................................195

4. “Enforcement” of system integrity/Federal role .......................................................................195

D. System governance and why it is important .................................................................................196

1. Public model .............................................................................................................................199

2. Public-private partnership model..............................................................................................200

3. Private model ............................................................................................................................200

4. Scope of the SCMS system governance....................................................................................204

X. Legal Liability...................................................................................................................................208

A. Overview.......................................................................................................................................208

B. Industry’s liability concerns and solutions....................................................................................208

C. Liability concerns specific to the SCMS.......................................................................................211

D. Federal liability limiting mechanisms...........................................................................................211

E. NHTSA’s assessment of industry liability....................................................................................212

F. NHTSA’s assessment of SCMS liability ......................................................................................213

XI. Preliminary Cost Estimates of V2V Implementation....................................................................216

A. Overview of preliminary estimated V2V costs and benefits ........................................................216

B. Discussion of V2V preliminary cost estimates.............................................................................217

C. Projected vehicle equipment costs................................................................................................218
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1. OEM devices.............................................................................................................................219

2. Aftermarket devices..................................................................................................................227

3. How the preliminary projected vehicle equipment cost estimates were developed..................230

D. Projected fuel economy impact – fuel costs for increased weight ................................................233

1. Fuel price and estimated miles per gallon.................................................................................234

2. Vehicle miles traveled and survivability...................................................................................235

3. Incremental weight from V2V equipment ................................................................................235

4. Summary of fuel economy impact............................................................................................236

E. Preliminary system communication costs.....................................................................................236

1. Certificate revocation list..........................................................................................................238

2. Alternative communication systems.........................................................................................241

3. System requirements/network options......................................................................................242

4. Communication costs conclusions............................................................................................251

F. Security credentials management system cost modeling..............................................................252

1. Preliminary projected costs for SCMS......................................................................................252

2. Funding the SCMS....................................................................................................................256

G. Conclusion of preliminary V2V implementation cost estimates ..................................................256

H. Economic practicability ................................................................................................................257

XII. Preliminary Effectiveness and Benefits Estimates of V2V...........................................................259

A. Analysis of preliminary benefits of V2V technology ...................................................................259

1. Analysis overview.....................................................................................................................259

2. Technology implementation scenarios......................................................................................261

3. Target population for V2V technology.....................................................................................262

B. Effectiveness of the V2V safety applications...............................................................................266

1. Safety Impact Methodology - SIM ...........................................................................................267

2. Driving Simulator Study - MiniSim..........................................................................................272

3. Injury probability curves...........................................................................................................274

4. Crashworthiness effectiveness by MAIS ..................................................................................275

5. Effectiveness of Intersection Movement Assist - IMA.............................................................275

6. Effectiveness of Left Turn Assist - LTA ..................................................................................282

7. Summary of IMA and LTA effectiveness.................................................................................284

C. Fleet communication rate (Ci).......................................................................................................285

D. Projected benefits of V2V technology ..........................................................................................286
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1. Maximum annual estimated benefits ........................................................................................286

2. Annual Estimated Benefits by Calendar Year ..........................................................................287

XIII. Appendix A: Tables......................................................................................................................288

XIV. Appendix B: List of Policy, Standards and Research Needs.........................................................300

A. Policy needs..................................................................................................................................300

B. Standards needs.............................................................................................................................300

C. Research needs..............................................................................................................................300

XV. Appendix C: List of Tables, Figures and Equations.....................................................................301

A. Tables............................................................................................................................................301

B. Figures...........................................................................................................................................303

C. Equations.......................................................................................................................................303
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Acronyms

AAMVA American Association of Motor Vehicle Administrators 

ABS antilock braking system

ACM a la carte message set

ACN automatic crash notification

AERIS Applications for the Environment: Real-Time Information Synthesis 

AHS Automated Highway System Program 

ANPRM Advanced Notice of Proposed Rulemaking 

ARIB Association of Radio Industries and Businesses

ARINC Aeronautical Radio Incorporated 

ASD aftermarket safety device

ASTM American Society for Testing and Materials

ATM automatic teller machine 

ATMIA ATM Industry Association 

BAH Booz Allen Hamilton

BSM basic safety message

BSW blind spot warning 

CA certificate authority 

CAMP Crash Avoidance Metrics Partnership 

CAN controller area network

CARS Car Allowance Rebate System - "Cash for Clunkers"

CBP channel busy percentage 

CCH control channel

CFR Code of Federal Regulations

CICAS-V Cooperative Intersection Collision Avoidance System-Violation

CLW control loss warning 

CME certificate management entity 

CP certificate policy 

CRL certificate revocation list

CSR common safety request (message set )

CSW curve speed warning 

CVE Common Vulnerabilities and Exposures 

CVSS Common Vulnerability Scoring System 

DAC (V2V Light Vehicle) Driver Acceptance Clinics 

DCM device configuration manager 

DE data element

DF data frame

DG CONNECT European Commission Directorate General for Communication Networks,

Content and Technology 

DIACAP DOD Information Assurance Certification and Accreditation Process

DNPW do not pass warning
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DOD U.S. Department of Defense

DOT U.S. Department of Transportation

DSRC dedicated short-range communications

DSRCS Dedicated Short Range Communications Systems

DVI driver-vehicle interface

ECA enrollment certificate authority 

ECU electronic control unit

EEBL emergency electronic brake lights

EIA Energy Information Administration

ELVS End of Life Vehicle Consortium 

EPA Environmental Protection Agency

ESC electronic stability control

ETSI European Telecommunications Standards Institute

EU European Union

EUR European Union Region

FAA Federal Aviation Administration

FARS Fatality Analysis Reporting System

FCC Federal Communication Commission

FCW forward collision warning

FHWA Federal Highway Administration

FIPS Federal Information Processing Standards 

FMVSS Federal Motor Vehicle Safety Standard

FOT field operational test

FSS fixed satellite service 

FTC Federal Trade Commission

GDP gross domestic product

GES General Estimates System 

GHz gigahertz - frequency measurement 

GPS Global Positioning System

HIPAA Health Insurance Portability and Accountability Act 

HUD heads-up display

HV host vehicle 

HW hardware

ICA intersection collision avoidance

ICANN Internet Corporation for Assigned Names and Numbers

ID identification

IEEE Institute of Electrical and Electronics Engineers

IMA Intersection Movement Assist 

IPG inter-packet gap

ISACA Information Systems Audit and Control Association

ISM Industrial, Scientific and Medical 

ISTEA Intermodal Surface Transportation Efficiency Act 

ITIS Integrated Taxonomic Information System 

ITS Intelligent Transportation System

IVBSS Integrated Vehicle-Based Safety Systems
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IVI Intelligent Vehicle Initiative

JPO Joint Program Office

LA Linkage Authority 

LCW lane change warning

LDW lane departure warning

LLC logical link control 

LOP location obscurer proxy 

LTA left turn assist

LTAP/OD left turn across path/opposite direction

LTV Light-truck vehicle

LVD lead vehicle decelerating

LVM lead vehicle moving

LVS lead vehicle stopped

MA misbehavior authority 

MAC (Section IV) Message Authentication Code

MAC (Section VIII) Medium Access Control 

MAIS Maximum Abbreviated Injury Scale

MLIT Japanese Ministry of Land, Infrastructure, Transportation and Tourism 

MOU Memorandum of Understanding 

MY model year

NAS National Academy of Sciences 

NCAP New Car Assessment Program

NHTSA National Highway Traffic Safety Administration

NIST National Institute of Standards and Technology 

NPRM Notice of Proposed Rulemaking

NTCIP National Transportation Communications for Intelligent Transportation System 

Protocol 

NTIA National Telecommunications and Information Administration

NTTAA National Technology Transfer and Advancement Act 

OBE on-board equipment

OBU on board units

ODI Office of Defects Investigations

OE original equipment

OEM original equipment manufacturer

OST-R Department of Transportation Office of the Assistant Secretary for Research and 

Technology

OTA Over the air

OVW Oversize Vehicle Warning 

PC Passenger car

PCA Pseudonym Certificate Authority 

PCI DSS Payment Card Industry Data Security Standard 

PDO property-damage-only

PER packet error rate

PII Personally-identifiable information 

PKI public key infrastructure
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POC proof of concept

PPP public private partnership 

PPS pulse per second

PPSG NTIA’s Policy and Plans Steering Group 

PRA Paperwork Reduction Act 

PSID provider service identifier

PTE position tracking error 

RA registration authority 

RCVW railroad crossing violation warning 

RF radio frequency

RLVW red light violation warning 

RSD retrofit safety device

RSE road-side equipment

RSU road side unit

RSZW reduced speed zone warning 

RTCM Radio Technical Commission for Maritime Services

RTK right turn into path

RV remote vehicle

SAE Society of Automotive Engineers

SCH service channel 

SCMS Security Credentials Management System 

SCP straight crossing path

SD secure digital 

SE system engineering 

SHRP2 Strategic Highway Research Program 2

SP single point

SPaT signal phase and timing

SSGA stop sign gap assist 

SSP service specific priority

SSVW stop sign violation warning 

STD Standard

SW Software

SWIW spot weather information warning 

TEA-21 Transportation Equity Act for 21st Century 

TESLA Timed Efficient Stream Loss-Tolerant Authentication

UBI usage based insurance 

UDP user datagram protocol

UMRA Unfunded Mandates Reform Act 

UMTRI University of Michigan Transportation Institute

U-NII Unlicensed-National Information Infrastructure

USDOT U.S. Department of Transportation

UTC Coordinated Universal Time

V2I Vehicle to Infrastructure

V2V Vehicle to Vehicle

V2X Vehicle to Other [pedestrian, bicycle, etc.]
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VAD vehicle awareness device

VII vehicle infrastructure integration

VIIC Vehicle-Infrastructure Integration – Consortium

VIN Vehicle Identification Number

VMT vehicle miles traveled

VSC vehicle safety communications

VSL value of statistical life 

VTTI Virginia Tech Transportation Institute 

WAAS Wide Area Augmentation System

WAVE Wireless Access for Vehicular Environments

WLAN wireless local area network 

WRV warning range variance 

WSM wave short message

XML Extensible Markup Language
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I. Executive Summary

The National Highway Traffic Safety Administration helps to reduce deaths, injuries, and 

economic losses resulting from motor vehicle crashes by setting and enforcing safety 

performance standards for motor vehicles and motor vehicle equipment. Vehicle manufacturers 

respond to NHTSA’s standards by building safer vehicles. Combined with State and local 

government efforts, market effects, and driver behavior improvements, NHTSA’s standards have 

contributed to a significant reduction in annual highway fatalities and injuries, from 52,627 

fatalities in 1970,1 to 32,479 fatalities in 2011.2

The purpose of this research report is to assess the readiness for application of vehicle-tovehicle (V2V) communications, a system designed to transmit basic safety information between 

vehicles to facilitate warnings to drivers concerning impending crashes. The United States 

Department of Transportation and NHTSA have been conducting research on this technology for 

more than a decade.

Safety technology has developed rapidly since NHTSA began regulating the auto 

industry – vehicles protect occupants much better in the event of a crash due to advanced 

structural techniques propagated by more stringent crashworthiness standards, and some crash

avoidance technologies are now standard equipment. Between existing crashworthiness and 

required standard crash avoidance technologies, motor vehicles are safer now than they have 

ever been.

However, a significant number of annual crashes remains that could potentially be 

addressed through expanded use of more advanced crash avoidance technologies. The agency 

estimates there are approximately five million annual vehicle crashes, with attendant property 

damage, injuries, and fatalities. While it may seem obvious, if technology can help drivers avoid 

crashes, the damage due to crashes simply never occurs.

The agency’s push thus far for adoption of crash avoidance technologies, like electronic 

stability control, has helped vehicles react to crash-imminent situations, but has not yet been able 

to help the driver react ahead of time. To fill that gap, some of the most advanced crash 

 

1 National Center for Health Statistics, HEW and State Accident Summaries (Adjusted to 30-Day Traffic Deaths by 

NHTSA).

2 National Highway Traffic Safety Administration, Fatality Analysis Report System (FARS) final 2011 data. For 

more information, see: www.nhtsa.gov/FARS (last accessed Feb. 12, 2014).
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avoidance technologies present on vehicles today include a host of on-board sensors, cameras, 

and radar applications. These technologies may warn drivers of impending danger so that the 

driver can take corrective action, or may even be able to intervene on the driver’s behalf.

While these “vehicle-resident” crash avoidance technologies can be highly beneficial, 

V2V communications represent an additional step in helping to warn drivers about impending 

danger. V2V communications use on-board dedicated short-range radio communication devices 

to transmit messages about a vehicle’s speed, heading, brake status, and other information to 

other vehicles and receive the same information from the messages, with range and “line-ofsight” capabilities that exceed current and near-term “vehicle-resident” systems -- in some cases,

nearly twice the range. This longer detection distance and ability to “see” around corners or 

“through” other vehicles helps V2V-equipped vehicles perceive some threats sooner than 

sensors, cameras, or radar can, and warn their drivers accordingly. V2V technology can also be 

fused with those vehicle-resident technologies to provide even greater benefits than either 

approach alone. V2V can augment vehicle-resident systems by acting as a complete system, 

extending the ability of the overall safety system to address other crash scenarios not covered by 

V2V communications, such as lane and road departure. A fused system could also augment 

system accuracy, potentially leading to improved warning timing and reducing the number of 

false warnings. For a discussion of NHTSA’s views as to how the various levels of vehicle 

automation will play an important role in reducing crashes and how on-board systems may 

someday work cooperatively with V2V technology, see NHTSA’s Preliminary Statement of 

Policy on Vehicle Automation (May 2013).3

For several years, NHTSA has been working under a self-imposed goal of making an 

agency decision regarding light-duty V2V communication systems in 2013. NHTSA 

substantially completed the work necessary to reaching that decision by the end of 2013, and 

announced that decision in early 2014. “Agency decision,” in this case, means the agency’s 

choice of the best course of action with regard to exercise of its regulatory and research authority 

in the V2V context. Among the factors considered in making that decision were NHTSA’s 

preliminary estimates of V2V technology’s ability to reduce fatalities and injuries from motor 

vehicle crashes; the practicality of the technology from the perspectives of maturity, cost, 

reliability, and performance; and the existence of ways to test and measure V2V technology 

performance objectively. 

The objective of this report is to analyze the research conducted thus far, the 

technological solutions available for addressing the safety problems identified by the agency, the 

policy implications of choosing those technological solutions, legal authority and legal issues 

 

3 NHTSA’s Preliminary Statement of Policy on Vehicle Automation (May 2013). See

www.nhtsa.gov/staticfiles/rulemaking/pdf/Automated_Vehicles_Policy.pdf (last accessed Jan. 22, 2014).
xv

such as liability and privacy. Using this report and other available information, decision-makers 

will determine how to proceed with additional activities involving V2V, V2I, and V2P 

technologies.

In summary, based on the research and analysis conducted by NHTSA and its partners so 

far, it appears that:

• V2V devices installed in light vehicles as part of the Connected Vehicle Safety Pilot 

Model Deployment were able to transmit and receive messages from one another, with a 

security management system providing trusted and secure communications among the 

vehicles during the Model Deployment. This was accomplished with relatively few 

problems given the magnitude of this first-of-its-kind demonstration project. The V2V 

devices tested in the Model Deployment were originally developed based on existing 

communication protocols found in voluntary consensus standards from SAE and IEEE.

NHTSA and others participating in the Model Deployment (e.g., its research partners and 

devices suppliers) found that the standards did not contain enough detail and left too 

much room for interpretation. They therefore developed additional protocols that enabled 

interoperability between devices participating in the study. The valuable interoperability 

information learned during the execution of Model Deployment is planned to be included 

in future versions of voluntary consensus standards that would support a larger, 

widespread technology roll-out.

• As tested in the Model Deployment, safety applications enabled by V2V, examples of 

which include IMA, FCW, and LTA, have proven effective in mitigating or preventing 

potential crashes, but the agency recognizes that additional refinement to the prototype 

safety applications used in the Model Deployment would be needed before minimum 

performance standards could be finalized and issued. Based on the agency’s

understanding of how these prototype safety applications operate, preliminary 

effectiveness estimates indicate substantial ability to mitigate crashes, injuries or fatalities 

in these crash scenarios. Also, some safety applications could be better tailored to the 

safety problem that they are intended to solve (e.g., LTA applications currently trigger 

only when the driver activates the turn signal, but many drivers do not always activate 

their turn signals in dedicated turn lanes). Finally, more research would help the agency 

develop objective performance tests that would ensure consistent operation that is helpful 

to drivers.

• The agency has the legal authority to mandate V2V (DSRC) devices in new light 

vehicles, and could also require them to be installed in commercial vehicles already in 

use on the road. The agency also has the authority to mandate safety applications that are

V2V-based, and to work with an outside entity to develop the security and 
xvi

communications infrastructures required to support deployment of V2V technologies in 

motor vehicles.

• Based on preliminary information, NHTSA currently estimates that the V2V equipment 

and supporting communications functions (including a security management system) 

would cost approximately $341 to $350 per vehicle in 2020. It is possible that the cost 

could decrease to approximately $209 to $227 by 2058, as manufacturers gain experience 

producing this equipment (the learning curve). These costs would also include an 

additional $9 to $18 per year in fuel costs due to added vehicle weight from the V2V 

system. Estimated costs for the security management system range from $1 to $6 per 

vehicle, and they will increase over time due to the need to support an increasing number 

of vehicles with the V2V technologies. The communications costs range from $3 to $13 

per vehicle. Cost estimates are not expected to change significantly by the inclusion of

V2V-based safety applications, since the applications themselves are software and their 

costs are negligible.

• Based on preliminary estimates, the total projected preliminary annual costs of the V2V 

system fluctuate year after year but generally show a declining trend. The estimated total 

annual costs range from $0.3 to $2.1 billion in 2020 with the specific costs being 

dependent upon the technology implementation scenarios and discount rates. The costs 

peak to $1.1 to $6.4 billion between 2022 and 2024, and then they gradually decrease to 

$1.1 to $4.6 billion.

• In terms of safety impacts, the agency estimates annually that just two of many possible 

V2V safety applications, IMA and LTA, would on an annual basis potentially prevent

25,000 to 592,000 crashes, save 49 to 1,083 lives, avoid 11,000 to 270,000 MAIS 1-5 

injuries, and reduce 31,000 to 728,000 property-damage-only crashes by the time V2V 

technology had spread through the entire fleet. We chose those two applications for 

analysis at this stage because they are good illustrations of benefits that V2V can provide 

above and beyond the safety benefits of vehicle-resident cameras and sensors. Of course, 

the number of lives potentially saved would likely increase significantly with the 

implementation of additional V2V and V2I safety applications that would be enabled if 

vehicles were equipped with DSRC capability.

Even with the success of the Safety Pilot Model Deployment in proving that V2V 

technology can work in a real-world environment on actual roads with regular drivers, additional 

items need to be in place beyond having the authority to implement a V2V system, in order for a 

potential V2V system to be successful. These items include:
xvii

• Wireless spectrum: V2V communications transmit and receive messages at the 5.8-5.9 

GHz frequency. The FCC is currently considering whether to allow “Unlicensed National 

Information Infrastructure” devices (that provide short-range, high-speed, unlicensed 

wireless connections for, among other applications, Wi-Fi-enabled radio local area 

networks, cordless telephones, and fixed outdoor broadband transceivers used by wireless 

Internet service providers) to operate in the same area of the wireless spectrum as V2V.

Given that Wi-Fi use is growing exponentially, “opening” the 5.8-5.9 GHz part of the 

spectrum could result in many more devices transmitting and receiving information on 

the same or similar frequencies, which could potentially interfere with V2V 

communications in ways harmful to its safety intent. More research needs to be done on 

whether these Wi-Fi enabled devices can share the spectrum successfully with V2V, and 

if so, how.

• V2V device certification issues: V2V devices are different from other technologies 

regulated by NHTSA under the Federal Motor Vehicle Safety Standards, insofar as part 

of ensuring their successful operation (and thus, the safety benefits associated with them) 

requires ensuring that they are able to communicate with all other V2V devices 

participating in the system. This means that auto manufacturers (and V2V device 

manufacturers), attempting to comply with a potential V2V mandate, could have a 

significant testing obligation to guarantee interoperability among their own devices and 

devices produced by other manufacturers. It is an open question whether individual 

companies could meet such an obligation themselves, or whether independent testing 

facilities might need to be developed to perform this function. Based on the current 

security design, it also is likely that the entity or entities providing the security 

management system would require that device manufacturers comply with 

interoperability certification requirements to ensure the reliability of message content.

• Test procedures, performance requirements, and driver-vehicle interface issues: While 

existing test procedures, performance requirements, and driver-vehicle interfaces appear 

to be working well enough for purposes of the Model Deployment (as compared to a true 

production, real-world environment), additional research and development would be 

necessary to produce FMVSS-level test procedures for V2V inter-device communication 

and potential safety applications.

NHTSA is currently engaged in research to examine the minimum performance measures 

for DSRC communication and system security. This research will include functional and 

performance requirements for the DSRC device and is intended to include how to address 

end-of-life issues on the DSRC components and security system.

To eventually go forward with rulemaking involving safety applications, V2V and safety 

application standards need to be objective and practicable, meaning that technical 
xviii

uncertainties are limited, that tests are repeatable, and so forth. Additionally, the agency 

has yet to determine whether standardization of DVIs would improve the effectiveness of 

safety applications, and whether some kind of standardization could have significant 

effects on costs and benefits.

• Standing up security and communications systems to support V2V: In order to function 

safely, a V2V system needs security and communications infrastructure to enable and 

ensure the trustworthiness of communication between vehicles. The source of each 

message needs to be trusted and message content needs to be protected from outside 

interference. In order to create the required environment of trust, a V2V system must 

include security infrastructure to credential each message, as well as a communications 

network to get security credentials and related information from vehicles to the entities 

providing system security (and vice versa). NHTSA currently anticipates that private 

entities will create, fund, and manage the security and communications components of a 

V2V system. While NHTSA has identified several potential types of entities, including 

some specific entities, which might be interested in participating in a V2V security 

system, private entities have not committed to doing so to date.

• Liability concerns from industry: Auto manufacturers repeatedly have expressed to the 

agency their concern that V2V technologies will increase their liability as compared with 

other safety technologies. In their view, a V2V system exposes them to more legal risk

than on-board safety systems because V2V warning technologies rely on information 

received from other vehicles via communication systems that they themselves do not 

control. However, the decision options currently under consideration by NHTSA involve 

safety warning technologies -- not control technologies. NHTSA’s legal analysis 

indicates that, from a products liability standpoint, V2V safety warning technologies, 

analytically, are quite similar to on-board safety warnings systems found in today's motor 

vehicles. For this reason, NHTSA does not view V2V warning technologies as creating 

new or unbounded liability exposure for the industry.

• Privacy: At the outset, readers should understand some very important points about the 

V2V system as currently contemplated by NHTSA. The system will not collect or store

any data identifying individuals or individual vehicles, nor will it enable the government

to do so. There is no data in the safety messages exchanged by vehicles or collected by 

the V2V system that could be used by law enforcement or private entities to personally 

identify a speeding or erratic driver. The system—operated by private entities—will not 

enable tracking through space and time of vehicles linked to specific owners or drivers.

Third parties attempting to use the system to track a vehicle would find it extremely 

difficult to do so, particularly in light of far simpler and cheaper means available for that 

purpose. The system will not collect financial information, personal communications, or 

other information linked to individuals. The system will enroll V2V enabled vehicles 
xix

automatically, without collecting any information that identifies specific vehicles or 

owners. The system will not provide a “pipe” into the vehicle for extracting data. The 

system will enable NHTSA and motor vehicle manufacturers to find lots or production 

runs of potentially defective V2V equipment without use of VIN numbers or other

information that could identify specific drivers or vehicles. Our research to date suggests 

that drivers may be concerned about the possibility that the government or a private entity 

could use V2V communications to track their daily activities and whereabouts. However, 

as designed, NHTSA is confident that the V2V system both achieves the agency’s safety 

goals and protects consumer privacy appropriately.4

• Consumer acceptance: If consumers do not accept a required safety technology, the 

technology will not create the safety benefits that the agency expects. One potential issue 

with consumer acceptance is maintenance. If the security system is designed to require 

consumers to take action to obtain new security certificates – depending on the 

mechanism needed to obtain the certificates -- consumers may find the required action 

too onerous. For example, rather than return to a dealership periodically for a download 

of new certificates, consumers may choose instead to live with non-functioning V2V 

capabilities. The agency is exploring ways to make such downloads automatic, but more 

research is needed to understand this issue fully.

The above issues indicate that through the research conducted to date, the agency has a 

better understanding of the potential of V2V technology, but various aspects of the technology 

still need further investigation to support transition from a prototype-level to a deployment-level 

system. Further research to move toward deployment has been identified (and detailed in this 

report) and will be conducted to address the following:

• The impact of spectrum sharing with U-NII devices; 

• Development of performance requirements for DSRC devices;

• Development of performance requirements for safety applications;

• The potential establishment of device certification and compliance procedures;

• The ability to mitigate V2V communication congestion:

• Incorporation of GPS positioning advancements to improve V2V relative positioning;

• Remedies to address false positive warnings from V2V safety applications;

• Driver-vehicle interface performance to enhance crash avoidance warning effectiveness;

• An appraisal of consumer acceptance of the technology;

 

4 NHTSA acknowledges that privacy and system security are current and relevant areas of discussion and that some 

may have concerns about the vulnerability of this system to malicious attack. We understand those concerns and 

intend to explore the risks and safeguards fully in our in-depth analysis of system security. Recently, for example, 

we have been in contact with DARPA about possible protections against software vulnerabilities.
xx

• Evaluation of V2V system privacy risks; and

• An assessment of the security system to ensure a trusted and a safe V2V system.

The GAO report “Intelligent Transportation Systems, Vehicle-to-Vehicle Technologies 

Expected to Offer Safety Benefits, but a Variety of Deployment Challenges Exist”5 confirms the 

appropriateness of the research identified. This research will facilitate a comprehensive 

representation of a deployment-ready V2V system. NHTSA, with the Intelligent Transportation 

System Joint Program Office, has positioned the resources needed to accomplish this research to 

support the possible deployment of V2V given any agency action. 

 

5 Intelligent Transportation Systems: Vehicle-to-Vehicle Technologies Expected to Offer Safety Benefits, but a 

Variety of Deployment Challenges Exist (Nov. 2013, GAO-14-13). See www.gao.gov/assets/660/658709.pdf (last 

accessed Feb. 12, 2014).
1

II. Introduction

A. Purpose of this report

For several years, NHTSA has indicated its intention to make an agency decision 

regarding light-duty V2V communication systems in 2013.6 NHTSA substantially completed the 

work necessary to reaching that decision by the end of 2013, and announced that decision in 

early 2014. “Agency decision,” in this case, referred to the agency’s choice of the best course of 

action with regard to exercise of its regulatory and research authority in the V2V context. Among 

the factors considered in making that decision were V2V technology’s ability to reduce fatalities 

and injuries from motor vehicle crashes; the practicality of the technology from the perspectives 

of maturity, cost, reliability, and performance; and the existence of ways to test and measure 

V2V technology performance objectively.

The objective of this report is to assess the readiness for application of V2V 

communications technology, by discussing the research conducted thus far, of the technological 

solutions available for addressing the safety problems identified by the agency, the policy 

implications of choosing those technological solutions, the agency’s legal authority and related 

legal issues such as liability and privacy, and potential implementation options available to the 

agency for creating a national V2V system. Using this report and other available research, 

agency decision-makers determined how to proceed with additional activities involving vehicleto-vehicle, vehicle-to-infrastructure, and vehicle-to-pedestrian technologies.

In September 2012, NHTSA’s Senior Associate Administrator for Vehicle Safety formed 

the V2V Decision Team to examine these and other related issues and summarize the current 

state of knowledge on V2V. The team consisted of members from the NHTSA’s offices of 

Vehicle Safety Research, Rulemaking, Enforcement, the NHTSA National Center for Statistical 

Analysis, and Chief Counsel and from the Federal Highway Administration, the Department of 

Transportation’s Office of the Assistant Secretary for Research and Technology (OST-R), the 

DOT’s John A. Volpe National Transportation Systems Center and the Intelligent Transportation 

System Joint Program Office (ITS-JPO).7

In particular, ITS-JPO, OST-R, and FHWA played a vital supporting role in the analysis 

by representing the broader interests of DOT’s Intelligent Transportation Systems wide-ranging 

programs and assessing the potential impacts that an agency decision on V2V technology could 

 

6 E.g., NHTSA Vehicle Safety Rulemaking and Research Priority Plan 2009-2011 (July 2009, Docket No. NHTSA2009-0108-0001) and NHTSA Vehicle Safety and Fuel Economy Rulemaking and Research Priority Plan 2011-

2013 (March 2011, Docket No. NHTSA-2009-0108-0032). See www.nhtsa.gov/Laws-Regs (last accessed Jan. 23, 

2014).

7 For more information on ITS-JPO, see www.its.dot.gov.
2

have. Additionally, ITS-JPO has been a supporting partner throughout the Connected Vehicle8

Safety Pilot program,

9

working collaboratively with NHTSA’s Vehicle Safety Research office to 

develop and execute the valuable information obtained by the program and used, in part, to 

inform the agency decision on V2V technology.

The Volpe Center played a vital role, as it does with many DOT programs, by providing 

critical expertise in the many specialized areas of both ITS and V2V. For example, Volpe Center 

experts developed and validated the Simulation Tool used for determining the preliminary V2V 

system benefits for this analysis. Additionally, the Volpe Center is contracted to operate as the 

Independent Evaluator of the data collected during the Safety Pilot Model Deployment.

This report was presented by the team to the SAA and constitutes analysis of the relevant 

issues and suggestions on various options before the agency. After full discussion of the report 

and the issues with the political leadership in NHTSA and DOT, the agency reached its decision 

on the future course of agency action.

The report breaks down the decision by describing and examining elements of the 

technology and the deployment of the technology using the results of available research. The 

sections of this report cover:

• how the technology addresses the safety need;

• an investigation of the legal and policy issues associated with the secure operation of the 

technology and the implications of these issues for privacy;

• a description of the technology, the different types of devices, the elements of the 

devices, and the security needed for trusted communications; and

• how much the technology may be expected to cost, in terms of both consumer and 

operational costs and potential effectiveness and benefits of the technology (based on 

preliminary data).

 

8 DOT has long used the term “connected vehicle” to refer to the vehicle-to-vehicle communication technology that 

supports crash avoidance applications. However, more recently the term has also been associated with vehicle 

telematics that connects vehicles to various information and “infotainment” applications through other forms of 

communication. There will be references in this report to “connected vehicle” and in the context of this report these 

references are intended to mean V2X technology.

9 The Connected Vehicle Safety Pilot Program is a scientific research initiative that features a real-world 

implementation of connected vehicle safety technologies, applications, and systems using everyday drivers. The 

effort will test performance, evaluate human factors and usability, observe policies and processes, and collect 

empirical data to present a more accurate, detailed understanding of the potential safety benefits of these 

technologies. The Safety Pilot program includes two critical test efforts—the Safety Pilot Driver Clinics and the 

Safety Pilot Model Deployment. For more information, see www.its.dot.gov/safety_pilot/#sthash.LL2V6yT0.dpuf

(last accessed Jan.23, 2014).
3

B. History of V2V communication research program

1. History of ITS

Before Intelligent Transportation Systems (ITS), the United States developed, planned, 

and built the interstate highway system. The interstate highway system has provided a high level 

of mobility for citizens as well as the efficient movement of goods. From the 1950s through the 

1980s, the vision of highway transportation was focused on building roads. Yet issues began to 

emerge as the interstate system was being built: about traffic congestion, especially in our urban 

centers; about highway-related fatalities and injuries due to crashes; and about the impacts on 

energy consumption and air quality.

As early as 1986, a group of transportation professionals from academia, Federal 

agencies, State transportation agencies, and the private sector started to discuss the future of 

transportation in relation to the post-interstate era.10 New transportation legislation needed to be 

developed, meaning that a new transportation paradigm needed to be invented that would use the 

current infrastructure, but also address the issues of safety, congestion, and environment.

The discussions culminated in a workshop held in Dallas, Texas, in 1990. During the 

workshop, participants invented the Intelligent Vehicle Highway Systems (IVHS) concept, 

which was later renamed to ITS.

11 The overall precept was that new transportation efficiencies 

could be found if current infrastructure could be married with advanced technology. New 

developments in computing, sensors, information systems, and advanced mathematical methods 

could be used to increase the operational capacity of the system, and achieve better overall 

transportation network operations.

The ITS concept became an integral part of the 1991 Intermodal Surface Transportation 

Efficiency Act (ISTEA). The Act allocated $660 million of funds for ITS research, development,

and operational tests over six years. In addition, just before the Act was adopted, the Intelligent 

Vehicle Highway Society of America advisory organization was established; later renamed 

Intelligent Transportation Society of America. This advisory organization developed the first 

strategic plan for ITS in 1992. The plan called for the integrated operation of the system using 

technology to bring together information about modes and current conditions, and discussed how 

institutions can be organized to operate the total transportation network.12

 

10 Perspectives on Intelligent Transportation Systems (Sussman, 2005). See Docket No. NHTSA-2014-0022 11 Sustainable Build Environment, Vol. II, Intelligent Transportation Systems (Williams). See

www.eolss.net/Sample-Chapters/C15/E1-32-08-05.pdf (last accessed Jan. 23, 2014). 12 The 1992 Strategic Plan by IVHS. See http://ntl.bts.gov/lib/jpodocs/repts_pr/1823.pdf (last accessed Jul. 12, 

2013).
4

ITS covers many areas that have been adjusted and renamed over the years, but the basic 

tenets of safety, mobility, and environment have remained. The components of ITS have been 

characterized by various management systems (areas). The management systems cover 

information, traffic (signal systems and tolling), designated Advanced Traffic Management 

Systems, and Advanced Vehicle Control Systems. Over the years, the integration of 

transportation and technology has continued. Currently, Congress authorizes approximately $100 

million a year for the continued research and development of ITS.13

There are a number of ITS program-developed applications deployed throughout the 

nation. These include both automated toll collection along with advanced traffic signal control 

systems and centers that monitor a region’s transportation network to address network issues in 

real time.

Many involved with ITS research and development view the development of the 

capability to provide connectivity to the transportation system as the next frontier, in order to 

further improve safety, mobility, and the environment. Using DSRC in the mobile environment 

may support that connectivity for an array of transportation applications.14

Envisioning that vehicles communicating with other vehicles around them could identify 

potential crash situations and alert the drivers so that these situations could be avoided, DOT and 

the Crash Avoidance Metrics Partnership (CAMP) initiated the first V2V research in December 

2006. DSRC, as a Wi-Fi-based technology, provides 360 degrees of coverage, whereas vehiclebased sensors can be more limited in terms of direction and distance at which they are able to 

detect a potential conflict. V2V systems predominantly apply to crashes with multiple vehicles, 

and these systems have the potential to address a large number of crashes.

2. History of V2V research program and its role in ITS

V2V communications research initially began under the Vehicle Infrastructure 

Integration Initiative in 2003, but its origins date back to the Automated Highway System (AHS)

research of the 1990s.

The actual initiation of advanced technology research was mandated by the ISTEA.15 The

Act called for the development of an automated intelligent vehicle highway prototype that would 

use technology to make highway driving efficient, safe, and predictable. The effort was 

 

13 Moving Ahead for Progress in the 21st Century Act (MAP-21) at sec. 51001(a)(4) (Pub.L.112-141; July 6, 2012). 

See www.gpo.gov/fdsys/pkg/PLAW-112publ141/pdf/PLAW-112publ141.pdf (last accessed Jan. 23, 2014) 14 ITS Strategic Research Plan 2010-2014, Progress Update 2012 (FHWA-JPO-12-019). See

www.its.dot.gov/strategicplan/pdf/ITS%20Strategic%20Plan%20Update%202012.pdf (last accessed Jan. 24, 2014). 15 For more information, see the Automated Highway System, Public Roads (Summer 1994, Vol. 58, No. 1, Nita 

Congress) at www.fhwa.dot.gov/publications/publicroads/94summer/p94su1.cfm (last accessed Jan. 24, 2014).
5

designated the “Automated Highway System Program.” The goal of the effort was to have a fully 

automated roadway or test track in operation by 1997.

The AHS Program started in 1992 as part of DOT’s ITS initiative that fell within the 

Advanced Vehicle Control Systems Area. Research activities looked into 16 different precursor 

areas to support the design of a prototype automated highway. The basic concept was that 

sensors in the roadway would communicate with sensors on the vehicle, to enable “hands-off”

and “feet-off” but not “mind-off” driving. For the first time, the roadway and the vehicle would 

actually be connected.

The AHS concept required dedicated lanes that would contain magnetic nails that the 

vehicle sensors would recognize and use to guide the vehicle down the intelligent lane. The 

benefits of AHS would theoretically be derived from decreasing the amount of driver error; 

increasing the capacity of the highway; facilitating reduced fuel consumption and tailpipe 

emissions; and providing more efficient commercial and transit operations.

The research culminated in a 1997 demonstration conducted on I-15 in San Diego, 

California, with more than 20 AHS-equipped vehicles demonstrating hands- and feet-off driving.

However, the idea that AHS needed dedicated lanes for the equipped vehicles posed a problem 

of where to put those lanes and how to finance them. AHS provided a glimpse of one possible 

future, but priorities changed in 1998 and the emphasis in relation to highway automation was 

refocused on developing technology that could address near-term safety.16

After AHS, DOT introduced the Intelligent Vehicle Initiative (IVI) in 1997, which was 

authorized in the 1998 Transportation Equity Act for 21st Century (TEA-21). The objectives of 

IVI were to: (1) prevent driver distraction, and (2) facilitate accelerated deployment of crash 

avoidance systems.17 Intelligent vehicle technology included development of vehicle-based and 

infrastructure-cooperative assistance products that would help drivers operate more safely and 

effectively. The premise of the IVI program was “to develop and deploy intelligent vehicle 

systems that completely consider the driver’s capabilities and limitations, rather than focus on 

developing highway infrastructure technology.”18

In relation to the prevention of driver distraction, studies were conducted that examined 

the relationship between distraction and crashes; ways to measure distraction and driver 

 

16 Traffic Technology International, Whatever Happened to Automated Highway Systems (AHS)? (AugustSeptember 2001). See http://faculty.washington.edu/jbs/itrans/bishopahs.htm (last accessed Jan. 24, 2014). 17 Saving Lives Through Advanced Vehicle Safety Technology, Intelligent Vehicle Initiative, Final Report, 

(September 2005, FHWA-JPO-05-057). See http://ntl.bts.gov/lib/jpodocs/repts_pr/14153_files/ivi.pdf (last accessed 

Jan. 24, 2014).

18 An Overview of Automated Highway Systems (AHS) and the Social and Institutional Challenges they Face 

(Cheon). See www.uctc.net/papers/624.pdf (last accessed Jan. 24, 2014).
6

workload; and ways to assess the impact of in-vehicle information on distraction and safety.19

The results of the driver distraction research suggested that the chaotic nature of crashes 

precluded the possibility of developing and validating a quantitative model to predict crashes as a 

function of workload measures.

IVI also developed prototype crash avoidance systems using vehicle-based and 

infrastructure cooperative technology. The initiative sought to identify the safety problem; 

develop the performance requirements and specifications for prototypes that would address the 

safety problem; and, using promising technologies, to prototype and test those avoidance 

systems. Prototypes that were developed and tested addressed rear-end, road departure, vehicle 

stability (heavy truck), and intersection crashes. The results of the tests and field operational tests 

of the prototype systems provided a foundation, e.g., requirements such as the range needed for 

radar sensors and camera object-detection performance, for further research and private 

development of crash avoidance safety technologies.

As the IVI research was concluding, new developments in telecommunications prompted 

a new direction in relation to the interaction of vehicles and infrastructure. The Vehicle 

Infrastructure Integration (VII) Initiative brought together the results of the IVI, the need for 

improved traffic operations, and the new developments in telecommunication technology. The 

focus of the VII initiative was to prove the concept that communications technology could be 

used to send information among vehicles and between vehicles and the infrastructure.20

At the 10th Intelligent Transportation Systems World Congress in Madrid, Spain, in 

November 2003, DOT announced the initiation of the VII initiative. This was made possible by 

the FCC allocating 75 MHz of spectrum at 5.9 GHz (where DSRC operates) for research 

purposes for improving transportation safety and use for other non-safety applications to improve 

transportation mobility.21

Using the spectrum and the foundation of crash avoidance research from past efforts, the 

vision for the VII initiative was to establish a small-scale implementation to test and evaluate the 

VII concept of operations. The basic VII concept of operations was that vehicle-to-vehicle and 

vehicle-to- infrastructure communication could support safety and mobility applications. To 

prove the concept, research and development needed to be conducted to establish the 

characteristics of the VII system (e.g., requirements and design specifications for vehicle and 

 

19 See supra note 17. 20 Final Report: Vehicle Infrastructure Integration Proof of Concept Executive Summary–Vehicle (May 19, 2009). 

See http://ntl.bts.gov/lib/31000/31100/31135/14477.htm (last accessed Jan. 24, 2014). 21 See

http://apps.fcc.gov/ecfs/document/view;jsessionid=zJy8QddC2zQpvYt2fTQdJTp1qLL3rTmmVZvxb13HPtzwtfMp

hskN!-856245186!973241960?id=6009850553 (last accessed Jan. 24, 2014).
7

infrastructure communications devices, network communication, and security and privacy 

protocols). In December 2006, the DOT entered into a cooperative agreement with five 

automotive original equipment manufacturers to investigate whether DSRC, in combination with 

GPS relative positioning, could improve performance of autonomous onboard crash warning 

systems or enable new communication-based safety applications.22

The concept was broken down by two distinct components of the system: the roadside 

network and the on-board vehicle equipment (OBE). The roadside network supported the 

communication of information between the system through the road-side equipment (RSE) to the 

OBE and from the OBE back to the system. The VII research tested the communication on both 

sides of the RSE. The network connected the RSEs via the system. To prove the concept,

prototypes of the roadside network (including RSEs) and the OBEs needed to be developed.

Besides equipment, message protocols needed to be established that allowed time-constrained

communications between OBEs and RSEs. The mobile communications would not have time to 

have devices establish a communication link between them in the way that current computers do 

with a wireless network, but messages still needed to be sent and received.

Laboratory and track tests were completed and the system was refined for an on-road 

proof of concept test. Data was collected to support analysis and the evaluation of the various 

components, including communications, the RSE, the network, and the OBEs. Key findings 

indicated that the VII concept was technically feasible; however, there were areas where the 

concept could be improved. Key areas that required more research included: (1) antenna 

placement for both OBEs and RSEs; (2) GPS positioning; (3) security for over the air 

communications; and (4) security systems operations.23

The VII Proof of Concept began with the vision that new telecommunication capabilities 

could be applied to transportation. It established DSRC as a means to connect vehicles and 

infrastructure via wireless communications. This foundation provided the information necessary 

to develop and plan the V2V Safety Application Research Plan and Safety Pilot. In addition, the 

success of the Proof of Concept provided the catalyst to create the Connected Vehicles Initiative.

 

22 Crash Avoidance Metrics Partnership (CAMP), Vehicle Safety Communications–Applications (VSC-A), Final 

Report at xi (September 2011, Report No. DOT HS 811 492A). See

www.nhtsa.gov/Research/Crash+Avoidance/Office+of+Crash+Avoidance+Research+Technical+Publications (last 

accessed Jan. 24, 2014).

23 Id.
8

3. The Connected Vehicle Safety Pilot Program

a) Introduction

The Connected Vehicle Safety Pilot Program is part of a major scientific research 

program run jointly by the DOT and its research and development partners in private industry. 

The program supports the development of safety applications based on V2V and V2I 

communications systems, using DSRC technology. The Safety Pilot Model Deployment was 

designed to inform the effectiveness estimates of these safety applications at reducing crashes 

and to show how real-world drivers respond to these safety applications in their vehicles. The 

test includes many vehicles with vehicle awareness devices, others with integrated safety 

systems, and others that use aftermarket safety devices to communicate with surrounding 

vehicles. All of these technologies are DSRC-based. The pilot includes multiple vehicle types—

cars, trucks, and transit vehicles. The Safety Pilot has concluded for purposes of gathering 

information on light-duty vehicles, but it has been extended for additional data collection through 

late 2014.

Figure II-1 Visual Representation of V2V Communication

Note: Vehicles “talk” to each other exchanging information such as vehicle size, position, speed, heading, lateral/longitudinal 

acceleration, yaw rate, throttle position, brake status, steering angle, wiper status, turn signal status, enabling safety and mobility 

applications.
9

While the ITS-JPO within the OST-R is leading this research initiative, several agencies 

within DOT are supporting the Safety Pilot, including NHTSA, FHWA, Federal Motor Carrier 

Safety Administration, and Federal Transit Administration.

b) Research vision

The vision of the Safety Pilot Model Deployment was to test V2V safety applications in 

real-world driving scenarios to support estimation of their effectiveness at reducing crashes, and 

to ensure that the devices are safe and do not unnecessarily distract motorists or cause 

unintended consequences. The Model Deployment is evaluating everyday drivers’ reactions,

both in a controlled environment through driver clinics, and on actual roadways with other

vehicles through the real-world model deployment.

c) Research plan

The two fundamental components of the Safety Pilot are:

Safety Pilot Driver Clinics: Driver clinics were conducted at six sites across the United 

States to assess user acceptance of the V2V technology. At each driver clinic, 

approximately 100 drivers tested in-vehicle wireless technology in a controlled 

environment, such as a race track. The goal was to determine how motorists responded to 

and benefitted from in-vehicle alerts and warnings. The driver clinics were conducted 

from August 2011 through January 2012.

Safety Pilot Model Deployment: The Model Deployment is being conducted in the Ann 

Arbor, Michigan, and ran from August 2012 to February 2014. Sponsored by DOT and 

conducted by the University of Michigan Transportation Research Institute, the 

experiment was designed to support estimation of the effectiveness of V2V technology at 

reducing crashes. Approximately 2,800 vehicles – a mix of cars, trucks, and transit 

vehicles operating on public streets within a highly concentrated area – are equipped with

integrated in-vehicle safety systems, aftermarket safety devices, or vehicle awareness 

devices, all using DSRC to emit wireless signals of vehicle position and heading 

information. Vehicles equipped with integrated in-vehicle or aftermarket safety devices 

have the additional design functionality of being able to warn drivers of an impending 

crash situation involving another equipped vehicle.

The Safety Pilot Model Deployment, with 27 roadside units covering 75 miles of 

roadway, is also designed to test V2I applications, including:

• Signal priority for transit and emergency vehicles,

• Roadway maintenance,

• Density of pedestrian traffic, and

• Traffic signal timing.
10

Data from the model deployment is being archived and made available to researchers for 

evaluation and testing of applications beyond the testing period. The model deployment 

is the first test of this magnitude of V2V technology in a real-world, multimodal 

operating environment. UMTRI is leading a diverse team of industry, public agencies, 

and academia in supporting this effort.

d) Research goals

The goals of the Safety Pilot were to:

• Support the NHTSA agency decision by obtaining empirical data on user 

acceptance and system effectiveness;

• Demonstrate real-world connected vehicle applications in a data-rich 

environment;

• Establish a real-world operating environment for additional safety, mobility, and 

environmental applications development;

• Archive data for additional research purposes; and

• Identify prototype system characteristics that can be improved or that need to be 

corrected.

e) Research results

The planned outcomes of this research are:

• A determination of whether the system as designed, or somewhat modified, is 

viable

• Documentation of information helpful in estimating the potential benefits of 

connected vehicle technologies and evaluation of driver acceptance of vehiclebased safety systems

• Identification of any research needs and the steps to address them

• Analysis of Model Deployment data to support making the agency decision on 

how to proceed.

4. Studies related to V2V light-vehicle research

As this report focuses on the basis and potential of applying V2V technology to light

vehicles, it important to note the agency is also heavily involved in V2V research related to 

heavy vehicles, pedestrians, and motorcycles.

a) Heavy vehicles

The agency intends to make a decision concerning the disposition of V2V technology 

concerning heavy vehicles in 2014. The heavy vehicle research is in parallel with the light

vehicle research. The interoperability, security, and safety application research associated with 

light vehicles directly supports the heavy vehicle research. Interoperable devices (both integrated 
11

and retrofit) were installed on heavy trucks and run during the Safety Pilot Model Deployment.

Heavy vehicle driver clinics were conducted to obtain feedback from professional drivers about 

V2V crash avoidance systems for heavy vehicles. Data collected during the Safety Pilot Model 

Deployment will be used to support an evaluation of the V2V technology, but meanwhile, the 

agency continues to conduct research to better understand the operational contrasts for these 

vehicles in terms of V2V technology and safety applications.

b) Pedestrians

Past investigation concerning preventing crashes with pedestrians has focused on vehiclebased sensors. The Pedestrian Crash Avoidance and Mitigation project studied the effectiveness 

of vehicle-based systems to detect a pedestrian in a possible crash situation with a vehicle and 

warn the driver. With V2V technology, pedestrians can carry devices (such as mobile phones)

that can send out a safety signal using DSRC and communicate with DSRC devices that would 

be used in vehicles. We envision that both the driver and the pedestrian could both be warned if a 

possible conflict arises. However, there are many issues to be resolved concerning V2P safety 

applications. The agency is developing a research plan that will investigate issues relating to V2P

communication, safety applications, and human factors, among other things. The initial research 

will identify the pre-crash scenarios involving pedestrians that can be addressed by V2P 

technology. That analysis will also provide information concerning the dynamics of each precrash scenario that will facilitate the prototyping of V2P safety applications.

c) Motorcycles

Motorcycle fatalities represent approximately 11 percent of all highway fatalities each 

year, and 80 percent of reported motorcycle crashes result in injury or death.24 A small group of 

motorcycles were outfitted with Vehicle Awareness Devices and participated in the Safety Pilot

Model Deployment. Using VADs on motorcycles enables the motorcycles to be “seen” by other

V2V-equipped vehicles, enabling alerts to the driver if a motorcycle and the equipped vehicle are 

in a possible crash situation. Subsequent analysis of the Safety Pilot Model Deployment data will 

provide information that will assist in the development of a V2V motorcycle research program.

V2V motorcycle research will likely entail investigating how to adapt safety applications to be 

used by motorcycles and addressing how to warn a motorcyclist of a possible crash situation, 

among other things.

5. Vehicle-to-infrastructure (V2I)

The same wireless technology that supports V2V safety applications (5.9 GHz DSRC) 

will also enable a broader set of safety and mobility applications when combined with 

 

24 Motorcycle Safety (Report No. DOT HS 807 709, revised December 2007). See

www.nhtsa.gov/people/injury/pedbimot/motorcycle/motosafety.html (last accessed Jan. 9, 2014).
12

compatible roadway infrastructure; therefore V2V serves as the gateway for the broader 

intelligent transportation system program. The Connected Vehicle Core System Architecture25

describes the overall anticipated system, including V2V and V2I capabilities. DSRC-based V2I

communications are also being developed that involve the wireless exchange of critical safety 

and operational data between vehicles (including brought-in devices) and highway infrastructure, 

intended primarily to avoid motor vehicle crashes while enabling a wide range of mobility and 

environmental benefits. The program is funding V2V and V2I communications research within 

the Dynamic Mobility Applications (real-time traffic information to enhance mobility), Road 

Weather, Applications for the Environment: Real-Time Information Synthesis (AERIS), and V2I 

Safety programs.

26 V2I applications under development include applications for commercial 

freight operators and transit agencies. V2I applications complement the V2V safety applications 

by addressing crash scenarios that the V2V program cannot address or that could be addressed 

more efficiently with low levels of penetration of DSRC-equipped light vehicles. The following 

is a list of V2I potential safety applications:

• Red Light Violation Warning,

• Curve Speed Warning,

• Stop Sign Gap Assist,

• Reduced Speed Zone Warning,

• Spot Weather Information Warning,

• Stop Sign Violation Warning,

• Railroad Crossing Violation Warning, and

• Oversize Vehicle Warning.

Additional mode-specific applications are being developed in partnership with FHWA, 

FTA, FMCSA, and the Federal Railroad Administration.

The V2I safety research program also focuses on creating national interoperability to 

support infrastructure and vehicle deployments and facilitating cost-effective infrastructure 

deployment. DOT and State and local agencies are implementing test beds in Michigan, 

California, Arizona, Florida, New York, Virginia, and Minnesota to analyze V2I and V2V 

communications systems. The ITS-JPO created a group27 for these entities to coordinate lessons 

learned, in particular related to the implementation of DSRC-based infrastructure.

 

25 See www.its.dot.gov/research/systems_engineering.htm (last accessed Jan. 9, 2014). 26 For detailed information on these programs, see www.its.dot.gov. 27 For information about the affiliation of Connected Vehicle Test Beds, see www.its.dot.gov/testbed.htm (last 

accessed Jan. 24, 2014).
13

The ITS-JPO also awarded a contract with the American Association of State Highway 

and Transportation Officials to conduct a “National Connected Vehicle Field Infrastructure 

Footprint Analysis.” This analysis was conducted to engage State and local departments of 

transportation in the development of concepts and scenarios for deployment of V2I systems that 

will be owned and operated by State and local DOTs. A final report, due later this year, will 

estimate costs for deployment and operations and maintenance of V2I. In addition to developing 

a concept for early deployments and a growing National Footprint for V2I systems, the analysis 

will serve as input to guidance that FHWA is preparing to release in late 2015. The FHWA 

Public Agency Guidance, currently under development, will initially focus on Federal-aid 

eligibility, use of right-of-way and infrastructure, innovative financing, procurement processes, 

and interoperability issues. This initial guidance is intended to address the needs of early 

demonstration site deployments, and to assist in planning for future investments and deployment 

of V2I systems. It is envisioned that deployment guidance will evolve as specific applications 

enter service.

The Basic Safety Message is the primary message set proposed to send data between 

vehicles and between vehicles and the infrastructure. While the BSM is mainly developed for 

safety applications, the data in the message may also be used by other connected vehicle

applications, such as mobility, weather, and AERIS programs. Additional messages from 

vehicles or from the infrastructure may also be developed in the future. Some of the applications 

can also deliver significant safety benefits once implemented. Currently, DOT is developing the 

applications and planning for field testing, evaluation, and modeling analysis of the benefits.

Also, mobility, weather, and environment applications will benefit from vehicles storing

certain limited types of data and, possibly, transmitting and receiving information over multiple 

communication media, such as DSRC and cellular. The NHTSA decision and market forces may 

have a role in encouraging vehicle manufacturers to provide storage and cellular capabilities that 

could facilitate mobility, weather, and environment applications. The following example 

describes why these capabilities are needed. DOT anticipates that few DSRC RSE units will be 

installed initially. In order to enable these applications, vehicles would need either to store data 

gathered along a trip and download it when reaching an RSE unit, or to transmit the information 

at regular intervals using cellular communications. Data may be used by the public sector to 

predict travel times along routes, as well as to identify incident locations or areas that may need 

salt treatments, in order to inform drivers about changes in traffic and road conditions. It will be 

important for vehicles to be able to receive V2I messages (e.g., Signal Phase and Timing,

traveler information messages).

Enabling these capabilities could likely require additional elements in the BSM and could 

also cause more data to be broadcast to and processed by devices, potentially leading to 

communication congestion. It is critical that safety messaging not be compromised due to 

broadcasting more data for V2I. Fortunately, it is likely that mobility, AERIS and weather 

applications will not need data transmitted 10 times per second. It is expected that the DOT’s 
14

ITS-JPO will conduct additional channel congestion analysis to understand the implication of 

communicating V2I data in addition to V2V data. The ITS-JPO will fund more V2I and V2V 

modeling and field testing, to be completed within 24 months after a NHTSA decision. The ITSJPO plans to perform the modeling and field tests and go through a peer review process with 

NHTSA to validate credibility of the methodology and results.
15

III. Safety Need

NHTSA was established by the Highway Safety Act of 1970, as the successor to the 

National Highway Safety Bureau, to carry out safety programs under the National Traffic and 

Motor Vehicle Safety Act of 1966 and the Highway Safety Act of 1966.28 Among other things, 

NHTSA helps to reduce deaths, injuries and economic losses resulting from motor vehicle 

crashes by setting and enforcing safety performance standards for motor vehicles and motor 

vehicle equipment, and through grants to State and local governments to enable them to conduct 

effective local highway safety programs. Vehicle manufacturers respond to NHTSA’s standards 

by building safer vehicles, and safety technology has developed rapidly since the 1970s – not 

only are air bags and ESC standard equipment now, but vehicles protect occupants better in the 

event of a crash due to advanced structural techniques propagated by more stringent 

crashworthiness standards. Combined with State and local government efforts, market effects, 

and driver behavior improvements, NHTSA’s standards have contributed to a significant 

reduction in highway fatalities and injuries - from 52,627 fatalities in 1970,29 to 32,479 fatalities 

in 2011.30 Between existing crashworthiness and crash avoidance technologies, motor vehicles 

are safer than they have ever been.

Nevertheless, crashes continue to occur, with attendant property damage, injuries, and 

fatalities. Although continued improvements in vehicle crashworthiness will still help reduce 

fatalities and injuries, NHTSA believes the greatest gains in highway safety in coming years will 

result from broad-scale application of crash avoidance technologies.31 Fortunately, the pace of 

technological development is picking up rapidly as advances in computers and electronics enable 

new crash avoidance technologies that may not only mitigate the remaining occurring crashes 

but avoid them entirely. By warning drivers of impending crash situations, V2V technology may 

be able to reduce the number and severity of motor vehicle crashes, thereby minimizing the costs

to society that would have resulted from these crashes.

 

28 NHTSA also carries out consumer programs established by the Motor Vehicle Information and Cost Savings Act 

of 1972.

29 National Center for Health Statistics, HEW and State Accident Summaries (Adjusted to 30-Day Traffic Deaths by 

NHTSA).

30 National Highway Traffic Safety Administration, Fatality Analysis Report System (FARS) final 2011 data. For 

more information, see www.nhtsa.gov/FARS (last accessed Feb. 12, 2014). 31 For more information, see the agency policy statement on automated vehicles at 

www.nhtsa.gov/staticfiles/rulemaking/pdf/Automated_Vehicles_Policy.pdf (last accessed Jan. 24, 2014).
16

A. Crashes potentially addressed by V2V technology

Calculating the target potential crashes that V2V-based safety applications could address 

helps provide a starting point for estimating the magnitude of the problem in terms of the number 

and severity of crashes and injuries, the number of fatalities, and the societal cost of vehicle 

crashes. Dividing up the potential target crashes by pre-crash scenario also helps us understand 

how different V2V-based safety applications can address different kinds of safety problems.

DOT conducted a preliminary analysis in 2009 of the annual number of crashes that 

could be addressed by V2V technology.

32 The identified applicable crashes are based on the 

DOT33developed pre-crash scenario typology as shown in Table III-1, which is in turn primarily 

based on pre-crash variables recorded in the GES and Crashworthiness Data System.

Table III-1 37 Pre-Crash Scenario Typology

Crash Scenario Crash Scenario

1 Vehicle Failure 21 Vehicle(s) Not Making a Maneuver – Opposite 

Direction

2 Control Loss with Prior Vehicle Action 22 Following Vehicle Making a Maneuver

3 Control Loss without Prior Vehicle Action 23 Lead Vehicle Accelerating

4 Running Red Light 24 Lead Vehicle Moving at Lower Constant Speed

5 Running Stop Sign 25 Lead Vehicle Decelerating

6 Road Edge Departure with Prior Vehicle Maneuver 26 Lead Vehicle Stopped

7 Road Edge Departure without Prior Vehicle 

Maneuver

27 Left Turn Across Path from Opposite Directions at 

Signalized Junctions

8 Road Edge Departure While Backing Up 28 Vehicle Turning Right at Signalized Junctions

9 Animal Crash with Prior Vehicle Maneuver 29 Left Turn Across Path from Opposite Directions at 

Non-Signalized Junctions

10 Animal Crash without Prior Vehicle Maneuver 30 Straight Crossing Paths at Non-Signalized 

Junctions

11 Pedestrian Crash with Prior Vehicle Maneuver 31 Vehicle(s) Turning at Non-Signalized Junctions

12 Pedestrian Crash without Prior Vehicle Maneuver 32 Evasive Action with Prior Vehicle Maneuver

13 Pedalcyclist Crash with Prior Vehicle Maneuver 33 Evasive Action without Prior Vehicle Maneuver

14 Pedalcyclist Crash without Prior Vehicle Maneuver 34 Non-Collision Incident

15 Backing Up into Another Vehicle 35 Object Crash with Prior Vehicle Maneuver

16 Vehicle(s) Turning – Same Direction 36 Object Crash without Prior Vehicle Maneuver

 

32 Frequency of Target Crashes for Intellidrive Safety Systems (Najm, Koopman, Smith, and Brewer, October 2010, 

Report No. DOT HS 811 381). See

www.nhtsa.gov/Research/Crash+Avoidance/ci.Office+of+Crash+Avoidance+Research+Technical+Publications.pri

nt (last accessed Jan. 30, 2014). 33 Analysis of Light Vehicle Crashes and Pre-Crash Scenarios Based on the 2000 General Estimates System (Najm, 

Sen, Smith, and Campbell, Nov. 2002, Report No. DOT HS 809 573). See

www.nhtsa.gov/Research/Crash+Avoidance/ci.Office+of+Crash+Avoidance+Research+Technical+Publications.pri

nt (last accessed Jan. 9, 2014).
17

17 Vehicle(s) Parking – Same Direction 37 Other

18 Vehicle(s) Changing Lanes – Same Direction

19 Vehicle(s) Drifting – Same Direction

20 Vehicle(s) Making a Maneuver – Opposite 

Direction

Vehicle Action refers to a vehicle decelerating, accelerating, starting, passing, parking, turning, backing up, 

changing lanes, merging, or successful corrective action to a previous critical event.

Vehicle Maneuver denotes passing, parking, turning, changing lanes, merging, or successful corrective action to a 

previous critical event.

Of these 37 pre-crash scenarios, DOT determined that 15 represented either single 

vehicle crashes or crashes that would need to be addressed by V2I. That left 22 pre-crash 

scenarios remaining that could potentially be addressed by V2V technology. The 22 remaining 

crash scenarios, if the crashes they represent could be prevented, could address 81 percent of 

unimpaired light vehicle crashes, Figure III-1.

Figure III-1 Target Unimpaired Light Vehicle Crashes Potentially Addressed by V2V

Using 2004-2008 crash data, the approximate average number of fatalities, injuries, and 

property damage per year caused by these 22 target light-vehicle pre-crash scenarios are 27,000; 

1,800,000; and 7,300,000, respectively, as illustrated in Figure III-2 below.
18

Figure III-2 22 Target Light-Vehicle Pre-Crash Scenario Crash Statistics

This analysis included the potential crashes that could be addressed by V2V technology 

only, V2I technology only, and combined. Overall, the DOT analysis concluded that, as a 

primary countermeasure, a fully mature V2V system could potentially address:

o about 4,409,000 police-reported or 79 percent of all vehicle target crashes,

o 4,336,000 police-reported or 81 percent of all light-vehicle target crashes, and 

o 267,000 police-reported or 81 percent of all heavy-truck target crashes annually.

Figure III-3 provides a graphical representation of how the potential crashes that could be 

addressed by V2V technology only were derived.
19

Figure III-3 V2V Light-Vehicle Target Crashes Breakdown

In addition, the analysis also indicated V2I systems could potentially address:

o about 1,465,000 police-reported or 26 percent of all-vehicle target crashes, 

o 1,431,000 police-reported or 27 percent of all light-vehicle target crashes, and

o 55,000 police-reported or 15 percent of all heavy-truck target crashes 

annually. 

And, finally, combined V2V and V2I systems could potentially address:

o about 4,503,000 police-reported or 81 percent of all-vehicle target crashes,

o 4,417,000 police-reported or 83 percent of all light-vehicle target crashes, and

o 272,000 police-reported or 79 percent of all heavy-truck target crashes 

annually.34

This preliminary analysis estimated the annual frequency of three different types of target 

crashes (i.e., light-vehicle, heavy-truck, and all-vehicle crashes) based on data from the General 

Estimates System (GES) crash database for 2005-2008, where: (1) Light-vehicle crashes are 

those that involve at least one light vehicle with gross vehicle weight rating (GVWR) of 10,000 

 

34 Id.
20

pounds or less; (2) Heavy-truck crashes are those that involve at least one heavy truck, single 

unit or multiple units, with GVWR over 10,000 pounds; and (3) All-vehicle crashes are those 

crashes involving both light vehicles and heavy trucks. The number of crashes reported by police 

for the crash types used in this analysis corresponds to the number of target crashes that might be 

addressed. The preliminary analysis also excluded drivers with physiological impairments (e.g., 

intoxication, drowsiness) because such driver conditions could be addressed by autonomous,

vehicle-based, countermeasure systems.

This preliminary estimate of annual crash frequency is broader than the benefits estimates 

used in Section XII below. Those estimates focus only on the usage of two applications (IMA 

and LTA). These applications are currently viewed as only able to be implemented by V2V 

technology. The estimates in Section XII, also do not take into account any potential V2I or 

autonomous applications, given that the agency is evaluating the readiness of V2V and not V2I 

or autonomous applications.

Once the preliminary analysis of which crashes V2V could potentially address was 

complete, the agency then focused its research efforts to develop priority scenarios based on the 

10 highest comprehensive cost and functional years lost values identified in Table III-2. The 

fatalities, injuries, and property damage caused by each of the crashes that occurred underlie the 

Comprehensive Costs and Functional Years Lost.

Table III-2 Societal Cost and Ranking of 22 Target Light-Vehicle Pre-Crash Scenarios

Pre-Crash Scenario

Light Vehicle V2V Crashes

Comprehensive Cost Functional Years Lost

Total Percent Rank Total Percent Rank

Control loss/no vehicle action $64,744,000,000 23.5% 1 469,000 24.1% 1

SCP @ non-signal $41,095,000,000 14.9% 2 292,000 15.0% 2

Rear-end/LVS $29,716,000,000 10.8% 3 198,000 10.2% 4

Opposite direction/no maneuver $29,558,000,000 10.8% 4 213,000 11.0% 3

Running red light $18,274,000,000 6.6% 5 129,000 6.6% 5

LTAP/OD @ non-signal $15,481,000,000 5.6% 6 111,000 5.7% 6

LTAP/OD @ signal $14,777,000,000 5.4% 7 105,000 5.4% 7

Rear-end/LVD $12,215,000,000 4.4% 8 82,000 4.2% 8

Rear-end/LVM $10,342,000,000 3.8% 9 72,000 3.7% 9

Changing lanes/same direction $8,414,000,000 3.1% 10 60,000 3.1% 10

Control loss/vehicle action $7,148,000,000 2.6% 11 51,000 2.6% 11

Turning/same direction $6,176,000,000 2.2% 12 43,000 2.2% 12

Opposite direction/maneuver $3,500,000,000 1.3% 13 25,000 1.3% 13

Drifting/same direction $3,483,000,000 1.3% 14 25,000 1.3% 14

Running stop sign $3,075,000,000 1.1% 15 22,000 1.1% 15

Rear-end/striking maneuver $2,381,000,000 0.9% 16 16,000 0.8% 16

Parking/same direction $1,095,000,000 0.4% 17 8,000 0.4% 17
21

Turn @ non-signal $930,000,000 0.3% 18 6,000 0.3% 18

Turn right @ signal $908,000,000 0.3% 19 6,000 0.3% 18

Backing into vehicle $874,000,000 0.3% 20 6,000 0.3% 18

Rear-end/LVA $667,000,000 0.2% 21 5,000 0.3% 21

Other $76,000,000 0.0% 22 - 0.0% 22

All $274,929,000,000 100.0% 1,944,000 100.0%

Comprehensive economic costs account for goods and services that must be purchased, 

or productivity that is lost, as a result of motor vehicle crashes. Comprehensive costs encompass 

medical, emergency medical service, market productivity, household productivity, insurance 

administration, workplace productivity, legal and court, travel delay, and property damage costs.

In addition, comprehensive costs include the value of a statistical life, the value of qualityadjusted life-years, and pain and suffering.

Functional years lost is a non-monetary measure that sums the years of life lost to fatal 

injury and the years of functional capacity lost to nonfatal injury. This measure does not mirror 

the monetary economic cost. It assigns a different value to the relative severity of injuries 

suffered from motor vehicle crashes. Table III-2 provides the annual values of comprehensive 

costs and functional years lost for the 22 target pre-crash scenarios involving two or more light 

vehicles based on 2004-2008 GES crash statistics of injured persons. These cost estimates reflect 

the injury levels of persons involved in only police-reported crashes.

Based on the target light vehicle crashes that can be addressed by V2V technology, Table 

III-3 extracts the number of crashes, injuries, and fatalities that form the basis for the 

development of the Comprehensive Cost and Functional Year Lost measures. Additional 

information regarding this data is available in Section XII. 
22

Table III-3 Light-Vehicle 2004-2008 GES Averages for V2V Target Pre-Crash Scenarios

0

None

1 

Minor

2

Moderate 

3

Serious

4

Severe

5

Critical

6

Fatal

LVS 942,000 204,027 299,750 33,389 8,815 1,761 562 811 1,080

LVD 398,000 77,805 115,948 13,082 3,542 720 230 397 528

LVM 202,000 42,752 66,363 7,866 2,288 480 163 701 933

Striking Maneuver 83,000 11,948 19,420 2,242 626 128 44 111 147

LVA 21,000 4,465 6,320 750 223 47 16 14 19

Same Direction 336,000 34,501 53,356 6,677 2,118 464 163 504 672

Turn - Same Direction 202,000 28,491 39,850 4,893 1,511 325 116 379 504

Drift - Same Lane 105,000 12,530 18,208 2,260 706 155 51 222 295

Maneuver 11,000 2,519 6,433 1,036 435 106 41 417 556

No Maneuver 118,000 25,589 58,025 9,035 3,660 875 344 3,501 4,663

@ Non Signal 184,000 50,160 89,482 11,644 3,830 853 296 970 1,293

@ Signal 204,000 62,164 108,673 13,940 4,450 975 334 605 805

SCP@ Non Signal 647,000 149,611 245,533 31,290 10,045 2,214 762 2,641 3,517

Turn Right @ Signal 31,000 3,474 5,388 603 153 29 9 77 103

Turn @ Non Signal 45,000 5,408 7,811 925 263 54 18 38 50

Total 3,529,000 715,444 1,140,560 139,632 42,665 9,186 3,149 11,388 15,165

5,764,645 995,019 1,712,336 220,355 71,756 15,883 5,591 25,885

61 72 67 63 59 58 56 44

Total All Light Vehicle Crashes

% of Total Light Vehicle Crashes

Adj. Fatalities 

Based on FARS

Lane 

Change

Opposite 

Direction

LTAP/OD

Junction 

Crossing

MAIS Injury Code

Rear End

Pre-crash 

Scenario 

Group

Pre-crash Scenario

Total No. 

Of 

crashes

From the 10 pre-crash scenarios prioritized by the agency, CAMP identified five initial, 

prototype V2V safety applications that could address these scenarios. It was found that these 

prototype applications could also address seven other pre-crash scenarios that were included in 

the overall list of 22 addressable by V2V, as shown in Table III-4 (Note: acronyms used in tables 

are explained in the list of acronyms at the front of this report). This includes the V2I safety 

application Traffic Control Device Violation pre-crash scenarios that can be addressed by the 

V2V Intersection Movement Assist safety application.
23

Table III-4 Groups of Target Light-Vehicle V2V Pre-Crash Scenarios and Associated 

Societal Cost

Light Vehicles V2V Crashes

Pre-Crash Scenario/Safety 

Application

Comprehensive Cost Functional Years Lost

Total Percent Rank Total Percent Rank

Rear 

End/Forward 

Collision 

Warning

Rear-end/LVS $ 29,716,000,000 10.8% 3 198,000 10.2% 4

Rear-end/LVD $ 12,215,000,000 4.4% 8 82,000 4.2% 8

Rear-end/LVM $ 10,342,000,000 3.8% 9 72,000 3.7% 9

Rear-end/striking 

maneuver $ 2,381,000,000 0.9% 16 16,000 0.8% 16

Rear-end/LVA $ 667,000,000 0.2% 21 5,000 0.3% 21

Total

$

55,321,000,000 20.1% 373,000 19.2%

Lane

Change/Blind 

Spot- Lane 

Change 

Warning

Changing 

lanes/same 

direction $ 8,414,000,000 3.1% 10 60,000 3.1% 10

Turning/same 

direction $ 6,176,000,000 2.2% 12 43,000 2.2% 12

Drifting/same 

direction $ 3,483,000,000 1.3% 14 25,000 1.3% 13

Total

$ 

18,073,000,000 6.6% 128,000 6.6%

Opposite 

Direction/Do 

Not Pass 

Warning

Opposite 

direction/no 

maneuver

$

29,558,000,000 10.8% 4 213,000 11.0% 3

Opposite 

direction/maneuver $ 3,500,000,000 1.3% 13 25,000 1.3% 13

Total

$ 

33,058,000,000 12.0% 238,000 12.2%

LTAP/OD/ Left 

Turn Assist 

Warning

LTAP/OD @ non 

signal

$

15,481,000,000 5.6% 6 111,000 5.7% 6

LTAP/OD @ 

signal

$

14,777,000,000 5.4% 7 105,000 5.4% 7

Total

$ 

30,258,000,000 11.0% 216,000 11.1%

Junction 

Crossing/Interse

ction Movement 

Assist

SCP @ non signal

$

41,095,000,000 14.9% 2 292,000 15.0% 2

Turn @ non signal $ 930,000,000 0.3% 18 6,000 0.3% 18

Turn right @ signal $ 908,000,000 0.3% 19 6,000 0.3% 18

Total $ 42,933,000,000 15.6% 304,000 15.6%

Traffic Control 

Device Violation

Running red light

$

18,274,000,000 6.6% 5 129,000 6.6% 5

Running stop sign $ 3,075,000,000 1.1% 15 22,000 1.1% 15

Total

$

21,349,000,000 7.8% 151,000 7.8%
24

The Safety Applications identified in Table III-4, except for the V2I safety application 

Traffic Control Device Violation, are represented by prototype applications in the Safety Pilot 

Model Deployment. These prototypes were developed by a consortium of OEMs working 

collaboratively in a pre-competitive environment. Data has been collected that provides 

information about the functional nature of these safety applications being used by regular drivers 

under real driving conditions. Analysis of the first 6 months of data identified the safety 

applications that most drivers experienced and for which the most data was collected. These 

safety applications were Forward Collision Warning, Intersection Movement Assist, Left Turn 

Assist, and Blind Spot Warning/Lane Change Warning. The amount of preliminary data 

collected on these four safety applications provided the information needed to estimate possible 

effectiveness and benefits these safety application may generate.

B. Potential for V2V to address vehicle crashes

The discussion up to this point has focused on determining the universe of crashes that 

V2V could address, and how a research program was developed and executed to prototype safety 

applications to address those crashes. The data collected during the Safety Pilot Model 

Deployment provide an indication of functional feasibility, along with information to evaluate 

the system – in effect, whether the prototypes and the system worked, but not necessarily how 

well they worked. Based on the information available to the agency at this time, Section XI starts 

to take the next step to analyze potential effectiveness and benefits that may accrue if these 

systems are implemented in the real world at production volumes.

In mass deployment, though, the agency would not expect benefits to accrue 

immediately. When V2V technology first begins to enter the fleet, it is possible (perhaps even 

likely) that vehicles equipped with the technology will encounter relatively few other vehicles 

also equipped with the technology – i.e., that V2V devices may not be able to “find” each other

for a while. Even if the market drives faster uptake by consumers of aftermarket devices (if, for 

example, auto insurance companies offer discounts for installing the devices), which would 

increase the ability of V2V devices to find each other earlier on, it will still take 37 years before 

we would expect the technology to fully penetrate the fleet. As a result, full knowledge of how 

different aspects of the V2V system perform – the ability of the security system to manage 

certification revocation lists for the complete U.S. vehicle fleet, for example – may be delayed.

However, as explained in Section XII, benefits would begin to appear in the first year. On 

the other hand, costs for the security system would be lower during initial deployment because 

there would be fewer vehicles requiring certificates. Over the 37 years, costs would increase in 

parallel with increased fleet penetration. Section XI discusses this issue of gradual roll-out of 

V2V technology and its implications in more detail.
28 

While a safety application as initially developed by an OEM or supplier may only address 

a subset of the pre-crash scenarios in the group, over time the safety application may be updated 

to include the other pre-crash scenarios as the technology and knowledge evolves. 

Another factor affecting costs and benefits would be what combination of safety 

applications are deployed in various vehicles. V2V devices in various vehicles may not be able 

to support all the safety applications.35 Depending on the type of device, different data elements 

may or may not be available, which may limit what safety applications can be supported. For 

example, a device that does not connect to a vehicle data bus may support forward collision 

warning, but without turn signal information, it may not support/implement left turn assist 

warning. 

The agency notes that crashes that can be prevented and lives that can be saved depends 

on the effectiveness of the safety applications. This report evaluates effectiveness estimates for 

two potential applications, IMA and LTA, but not for other potential safety applications such as 

LCW, FCW, CSW, etc. 

As such, the overall potential of V2V and the number of crashes prevented and lives 

saved is highly dependent on the number of safety applications deployed, the penetration of 

those applications in the fleet and the way in which the applications operate. For additional 

information on potential crashes prevented and lives saved using the IMA and LTA applications 

please refer to Section XII. 

C. Ways of addressing the safety need 

1. Scenarios addressed uniquely by vehicle-to-vehicle communications 

V2V technology communicates via radio signals, which are omnidirectional (i.e., offer 

360 degrees of coverage). Communicating via these signals allows two equipped vehicles to 

“see” each other at times when other vehicles that are only relying on their sensors are not able to 

detect the presence of another vehicle, let alone determine the other vehicle’s heading, speed, or 

its operational status. Figure III-4 depicts examples of safety applications and the scenarios they 

can address. 

 

35 Description of Light-Vehicle Pre-Crash Scenarios for Safety Applications Based on Vehicle-to-Vehicle 

Communications (Report No. DOT HS 811 731, May 2013). See

www.nhtsa.gov/Research/Crash+Avoidance/Office+of+Crash+Avoidance+Research+Technical+Publications (last 

accessed Jan. 27, 2014) 
26

Figure III-4 Examples of Crash Scenarios and Vehicle-to-Vehicle Applications

NOTE: Sensor-based crash avoidance technologies can, in some instances, provide warnings in forward collision, blind spot, and do not pass 

scenarios

V2V communications also offer an operational range of up to 300 meters between 

vehicles to facilitate identification of intersecting paths that may potentially result in a crash if no 

driver or vehicle action is taken. Additionally, a V2V system is not subject to the same weather, 

light, or cleanliness constraints associated with vehicle-resident sensors (e.g., cameras, lidar), 

although it is subject to other issues (e.g., urban canyons, GPS signal).36

There are three V2V safety applications that the agency believes are enabled by V2V 

alone and could not be replicated by any current, known vehicle-resident sensor- or camerabased systems, as discussed below.

 

36 A lidar device detects distant objects and determines the ir position, velocity, or other characteristics by analysis 

of pulsed laser light reflected from the ir surfaces. Lidar operates on the same principles as radar and sonar.
27

a) Intersection Movement Assist

IMA warns the driver of a vehicle when it is not safe to enter an intersection due to a high 

probability of colliding with one or more vehicles at intersections both where a signal is present 

(a “controlled” intersection) and those where only a stop or yield-sign is present (an 

“uncontrolled” intersection). Figure III-5 illustrates one possible IMA scenario.

Figure III-5 Example of V2V Intersection Movement Assist Warning Scenario

Note: In this scenario, the truck and sports utility vehicle are at risk of colliding because the drivers are unable to see 

one another approaching the intersection and the stop sign is disabled. Both drivers would receive warnings of a potential 

collision, allowing them to take actions to avoid it.

b) Left Turn Assist

LTA warns the driver of a vehicle, when they are entering an intersection, not to turn left 

in front of another vehicle traveling in the opposite direction.

c) Emergency Electronic Brake Light

Emergency Electronic Brake Light enables a vehicle to warn its driver to brake in a 

situation where another V2V-equipped vehicle decelerates quickly but may not be directly in 

front of the warning vehicle. The EEBL warning is particularly useful when the driver’s line of 

sight is obstructed by other vehicles or bad weather conditions, such as fog or heavy rain.

2. Scenarios also addressed by vehicle sensor-based systems

Two of the applications being evaluated by the agency are already available in production 

vehicles using vehicle-resident sensors: FCW and BSW. These applications have been available 

in a small number of production vehicles for many years. They could be considered mature 

technologies, insofar as they have undergone multiple generations of sensor technologies and 

variations of sensing technology to achieve their implementation.
28

V2V technology, however, could enable these applications independent of any vehicleresident sensors (e.g., cameras or lidar). At the same time, V2V could provide additional 

detection range for these applications, and/or detection agnostic to the weather, light or 

cleanliness constraints associated with vehicle-resident sensors such as cameras or lidar.

a) Forward Collision Warning

FCW warns the driver of the host vehicle in case of an impending rear-end collision with 

a remote vehicle ahead in traffic in the same lane and direction of travel.

The agency believes, based on current technology, that FCW systems using radar or 

cameras cannot provide a warning fast enough for very high speed rear end crashes. V2V, in 

contrast, has that capability based on its longer range (300 meters). Thus, fatal rear end crashes 

are one area where we believe V2V can provide some benefits not potentially covered by radarand camera-based systems.

Radar and camera FCW systems also have a problem detecting stopped vehicles if the 

vehicle is stopped before coming into range of the radar and camera. Recently, dual radar and 

dual camera systems have been developed to provide detection of stopped vehicles. A V2V 

system could act as the redundant system and allow a single radar or single camera FCW system 

to detect stopped vehicles, thus reducing system cost as compared to dual radar or dual camera.

b) Blind Spot Warning + Lane Change Warning

Blind Spot Warning +Lane Change Warning warns the driver of the host vehicle during a 

lane change attempt if the blind spot zone into which the host vehicle intends to switch is, or will 

soon be, occupied by another vehicle traveling in the same direction. The application also 

provides the driver of the host vehicle with advisory information that a vehicle in an adjacent 

lane is positioned in a vehicle’s “blind spot” zone when a lane change is not being attempted.

3. Scenarios possibly addressed by a combination of vehicle resident sensors and 

V2V communications

Other sensors such as radar, lidar, and cameras enable certain safety applications that are 

viewed by some as alternatives to V2V. While these systems might be more mature than V2V, 

they also have drawbacks when used alone; a combined or fused system using any of these other

sensors along with V2V will take advantage of the benefits of DSRC. For example, detection of 

threat vehicles not in the sensors’ field of view, and using a DSRC signal to validate a return 

from a vehicle-based sensor (i.e., a radar return off metal objects in the roadway, absent a DSRC 

signal identifying the sender as a vehicle, may be mistaken for a vehicle and cause a false 

warning).

A fused system would be able to use multiple sensors to augment accuracy, and could 

lead to improved warning timing and a reduction in the number of false positives. As stated in 
29

the agency policy statement on automated vehicles,

37 V2V technology could potentially also act 

as an additional sensor input that could augment data available.

D. Types of V2V devices

1. OEM devices

An OEM device is an electronic device built or integrated into a vehicle during vehicle 

production. An integrated V2V system is connected to proprietary data busses and can provide 

highly accurate information using in-vehicle information to generate the Basic Safety Message. 

The integrated system both broadcasts and receives BSMs. In addition, it can process the content 

of received messages to provide advisories and/or warnings to the driver of the vehicle in which 

it is installed. Because the device is fully integrated into the vehicle at the time of manufacture, 

vehicles with Integrated Safety Systems could potentially provide haptic warnings to alert the 

driver (such as tightening the seat belt or vibrating the driver’s seat) in addition to audio and 

visual warnings provided by the aftermarket safety devices. It is expected that the equipment 

required for an integrated OEM V2V system would consist of a general purpose processor and 

associated memory, a radio transmitter and transceiver, antennas, interfaces to the vehicle’s 

sensors, and a GPS receiver. Such integrated systems are capable of being reasonably combined 

with other vehicle-resident crash avoidance systems to exploit the functionality of both types of 

systems.

2. Aftermarket devices

a) Definition of an “aftermarket” device

Generally speaking, automotive aftermarket devices can be defined as any product with 

one or more functions in the areas of comfort, convenience, performance, or safety, which are 

added to a motor vehicle after its original assembly. An aftermarket V2V communication device 

provides advisories and warnings to the driver of a vehicle similar to those provided by an OEMinstalled V2V device. These devices, however, may not be as fully integrated into the vehicle as 

an OEM device, and the level of connection to the vehicle can vary based on the type of 

aftermarket device itself. For example, a “self-contained” V2V aftermarket safety device could 

only connect to a power source, and otherwise would operate independently from the systems in 

the vehicle. Aftermarket V2V devices can be added to a vehicle at a vehicle dealership, as well 

as by authorized dealers or installers of automotive equipment. Some aftermarket V2V devices 

(e.g., cell phones with apps) are portable and can be standalone units carried by the operator, the 

passenger, or pedestrians.

 

37 See www.nhtsa.gov/staticfiles/rulemaking/pdf/Automated_Vehicles_Policy.pdf (last accessed Feb. 20, 2014).
30

b) Types of aftermarket devices used in Safety Pilot Model Deployment

In the Safety Pilot Model Deployment, three types of aftermarket devices were installed 

into vehicles: vehicle awareness devices, aftermarket safety devices, and retrofit safety devices.

The VAD is the simplest design, and it only transmits a BSM to nearby vehicles. A VAD 

does not have any safety applications or DVIs, and it cannot provide any advisories or warnings 

to a driver. Installing these devices on existing vehicles could be an attractive option for fleet 

operators, rental agencies, or vehicle owners who could see benefit in signaling the presence of 

their vehicles to V2V-equipped vehicles and thus potentially avoiding crashes. Installation of 

VADs could increase deployment of V2V systems across the fleet as a whole, and thus 

potentially could increase the benefits for early adopters of this technology.

The ASD (referred to as a “self-contained” device in this research report in contrast to the 

terminology used in the Safety Pilot Model Deployment), is similar to the VAD, but also has the 

ability to both receive and transmit a BSM to nearby vehicles. Also, it contains safety 

applications that can provide advisories or warnings to the driver. Three suppliers developed and 

tested self-contained devices for use with light vehicles in the Safety Pilot Model Deployment. 

All suppliers developed and tested the following safety applications:

• FCW

• EEBL

• CSW38

The safety applications and warning functionality in both the ASDs and the V2V vehicles 

were similar, but the three self-contained device suppliers implemented only audible warnings 

for their devices, with no visual or haptic advisories or warnings presented to the driver. The 

agency originally specified a visual display for these devices, but the display selected by the 

suppliers did not meet the distraction guidelines for the Safety Pilot Model Deployment and was, 

therefore, not implemented as part of that testing.

The RSD is more fully integrated than the ASD: it connects to the vehicle and receives 

information from the vehicle’s data bus to support operation of various applications on the 

device. Although it is possible from a technical standpoint, light vehicles were not equipped with 

a RSD device in the Safety Pilot Modal Deployment, even though RSDs were deployed in heavy 

vehicles. The heavy truck RSDs demonstrated the following safety applications:

 

38 Some self-contained devices also had IMA capabilities and were track tested outside of the Safety Pilot Model 

Deployment, but did not meet performance requirements for purposes of inclusion in Model Deployment.
31

• FCW

• EEBL

• CSW

• BSW

• IMA

• Bridge Height Information

The advantage to RSDs, as compared to the other types of aftermarket devices, is that 

they can potentially perform different or enhanced safety applications or execute more 

sophisticated applications because they can access a richer set of data (i.e., data from the data 

bus). For example, having information on the turn signal status from the vehicle provides the 

device and application an indication of possible driver intent to make a turn, which can help 

inform the LTA, DNPW, and BSW/LCW safety applications. Therefore, the RSD is considered 

to be the closest of all of the aftermarket devices to a V2V device integrated into a new vehicle.

Table III-5 provides details on the three types of aftermarket safety devices employed in the 

Safety Pilot Model Deployment. The agency envisions these general types as models for 

potential commercial aftermarket devices that could be available to consumers.

Table III-5 Aftermarket Safety Device Types

Device Type Definition Method of Installation Functionality

Vehicle 

Awareness 

Device

Device is able to be 

connected to the vehicle for 

power source. Device 

provides Basic Safety 

Message for surrounding 

vehicles.

Device would need to be installed 

by a certified installer on vehicles 

not equipped with V2V 

technology to ensure correct 

antenna placement and security.

In the future, VADs might be 

mobile devices or stand-alone key 

fobs. 

• Transmits BSM

Aftermarket 

Safety Devices 

(i.e., Selfcontained)

Device is connected to the 

vehicle for power source, 

Device transmits BSM and 

receives BSMs to support 

safety applications for the 

driver of the vehicle in 

which it is installed.

This device only receives power 

from the vehicle; however, a 

certified installer would need to 

ensure correct antenna placement 

and security.

• V2V Safety 

applications

• Receives and 

Transmits BSM

• Driver-Vehicle 

Interface

Retrofit Safety 

Devices 

Device is connected to the 

vehicle’s data bus that 

provides BSM and safety 

applications for the driver 

of the vehicle in which it is 

installed.

This device needs to be connected 

to the vehicle’s data bus, 

therefore would require an 

installer that can access this for 

the particular make of vehicle.

Also, a certified installer would 

need to ensure correct antenna 

placement and security.

• V2V Safety 

applications

• Receives and 

Transmits BSM

• Driver Vehicle 

Interface

• Integration into the 

vehicle data bus 
32

3. Infrastructure-based devices

a) Infrastructure based devices that enable V2I

In addition to in-vehicle equipment, the Safety Pilot program is evaluating road side 

equipment with DSRC devices that allow vehicles to receive information from the infrastructure 

and allow vehicles to update their security certificates.39

This RSE can be co-located with infrastructure elements such as road signs, traffic 

signals, etc. The applications that the RSE is supporting in the Safety Pilot Model Deployment 

are signal phasing and timing (SPaT), and curve and curve speed warnings. There are twenty-six 

DSRC-equipped roadside units being used to support the program.

V2I communications involve the wireless exchange of critical safety and operational data 

between vehicles (including brought-in devices) and roadway infrastructure. V2I 

communications are intended primarily to avoid motor vehicle crashes while enabling a wide 

range of mobility and environmental benefits. The Connected Vehicle program is funding V2V 

and V2I communications research within the Dynamic Mobility Applications, Road Weather, 

AERIS, and V2I Safety programs.

b) What potential safety applications are enabled by V2I?

V2I applications complement the V2V safety applications by addressing crash scenarios 

that V2V applications cannot address and by more efficiently addressing some crash scenarios 

when there are low levels of penetration of DSRC-equipped light vehicles. The following is a list 

of contemplated, but not yet developed, V2I safety applications:

• Red Light Violation Warning: This technology will provide in-vehicle alerts to drivers 

about potential violations of upcoming red lights, based on vehicle speeds and distances 

to intersections.

• Curve Speed Warning: If a driver's current speed is unsafe for traveling through an 

upcoming road curve, this technology will alert the motorist to slow down.

• Stop Sign Gap Assist: This technology will assist drivers at STOP-sign-controlled 

intersections via vehicle gap detections, alerting motorists when it is unsafe to enter 

intersections.

• Reduced Speed Zone Warning: This technology will assist drivers in work zones, by 

issuing alerts to drivers to reduce speed, change lanes, and/or prepare to stop.

• Spot Weather Information Warning: This technology will provide in-vehicle alerts or 

warning to drivers about real-time weather events and locations, based upon information 

 

39 During the second phase of Safety Pilot, DSRC and cellular were used to provide vehicles with updated security 

certificates. 
33

from Roadside Equipment connections with Transportation Management Center and 

other weather data collection sites/services.

• Stop Sign Violation Warning: Based on vehicle speeds and distances to intersections, this 

technology will provide in-vehicle alerts to drivers about potential violations of 

upcoming stop signs.

• Railroad Crossing Violation Warning: This technology will assist drivers at controlled 

railroad crossings via RSE connections with existing train detection equipment, alerting 

motorists when it is unsafe to cross the railroad tracks.

• Oversize Vehicle Warning: Drivers of oversized vehicles will receive an in-vehicle alert 

to take an alternate route or a warning to stop, based upon information from RSE 

connections to infrastructure at bridges/tunnels.

Implementation of these V2I applications would require additional data elements to be 

broadcast to, and processed by, vehicles. Since the broadcasting of additional data has the 

potential of leading to communication congestion, DOT’s ITS JPO will conduct additional 

channel congestion analysis. It is critical that safety messaging should not be compromised due 

to broadcasting more data for V2I.

IV. Scope and Legal Authority

A. NHTSA’s scope and legal authority and how it applies to vehicle to 

vehicle communication

The National Traffic and Motor Vehicle Safety Act (the “Safety Act”) gives NHTSA 

broad statutory authority to regulate motor vehicles and items of motor vehicle equipment.40 As 

applied in this context, the agency’s authority includes all or nearly all aspects of a V2V system.

Congress enacted the Safety Act in 1966 with the purpose of reducing deaths and injuries as a 

result of motor vehicle crashes and non-operational safety hazards attributable to motor 

vehicles.41 The Safety Act, as amended, is now codified at 49 U.S.C. §§ 30101 et seq.

 

40 For more discussion and analysis of NHTSA’s authority to regulate advanced crash avoidance technologies, 

including V2V technologies, under the Safety Act, see the Potential Regulatory Challenges of Increasingly 

Autonomous Vehicles, 52 Santa Clara L. Rev. 1423 (Wood et al., 2012) at 

http://digitalcommons.law.scu.edu/lawreview/vol52/iss4/9/ (last accessed Mar. 4, 2014). 

For example, the agency’s authority to address the privacy and security of vehicle data associated with the operation 

of those technologies is discussed at length. Id., at pp. 1448, 1465-72. Addressing data security is necessary to 

safeguard the effectiveness of these technologies and promote the ir acceptance by vehicle users. Addressing privacy 

is similarly necessary to promote public acceptance. The views expressed in that article fairly encompass the 

agency’s views of its regulatory authority.

41 H.R. Rep. No. 89-1776, at 10 (1966).
34

The vehicle technologies that enable vehicles to talk to each other and to communicate 

with infrastructure are vastly different from those that existed when the Safety Act was enacted. 

Then, the vehicle operating systems were largely mechanical and controlled by the driver via 

mechanical inputs and linkages. Components and systems were either designed into the vehicle 

at the time of original manufacture or were later attached to or physically carried into the vehicle.

Sensing of a vehicle’s performance and the roadway environment was done solely by the driver.

Today, an increasing number of vehicle functions are electronic. These functions can be 

activated and controlled automatically and do not necessarily require driver involvement, unlike 

the mechanical functions of previous generations of vehicles. As discussed in much more detail 

in Section V.D below, V2V technologies rely on dedicated short-range radio communications 

(DSRC), which themselves require no driver involvement whatsoever in order to send and 

receive information that can be used for vehicle safety functions. Other ways in which V2V 

technologies differ from the mechanical technologies prevalent when the Safety Act was first 

enacted include the fact that how they operate can be substantially altered by post-manufacture 

software updates, and that advances in communications technology make it possible for nomadic 

devices with vehicle-related applications to be brought into the vehicle.

The language of the Safety Act, however, is broad enough to comfortably accommodate 

this evolution in vehicle technologies. NHTSA’s statutory authority over motor vehicles and 

motor vehicle equipment would allow the agency to establish safety standards applicable both to 

vehicles that are originally manufactured with V2V communications technologies and to 

aftermarket equipment that could be added to vehicles that were not originally manufactured as 

V2V-capable (i.e., to convert them into vehicles with various degrees of V2V-capability).

In the Safety Act, which gives NHTSA authority over new motor vehicles and motor 

vehicle equipment, “motor vehicle” is defined as a “vehicle driven or drawn by mechanical 

power and manufactured primarily for use” on public roads.42 The definition of “motor vehicle 

equipment,” as cited below, is broader and thus effectively establishes the limit of the agency’s 

authority under the Safety Act:

(A) any system, part, or component of a motor vehicle as originally manufactured;

(B) any similar part or component manufactured or sold for replacement or improvement 

of a system, part, or component, or as an accessory or addition to a motor vehicle; or

(C) any device or an article or apparel, including a motorcycle helmet and excluding 

medicine or eyeglasses prescribed by a licensed practitioner, that –

i) is not a system, part, or component of a motor vehicle; and

 

42 49 U.S.C. § 30102(a)(6).
35

ii) is manufactured, sold, delivered, or offered to be sold for use on public streets, 

roads, and highways with the apparent purpose of safeguarding users of motor 

vehicles against risk of accident, injury, or death.43

NHTSA’s authority to issue safety standards that apply to new motor vehicles would 

enable the agency to establish standards applicable to vehicles that were originally manufactured 

with V2V capabilities.44 This authority would also extend to the individual pieces of equipment 

that are installed in new vehicles to provide them with V2V capabilities.45 Using the agency’s 

authority over equipment, as described in (B) and (C) above, NHTSA could also establish safety 

standards that apply to equipment used to equip vehicles (not originally manufactured with V2V 

capabilities) with V2V capabilities.46

NHTSA’s authority over these groups of items – (1) systems, parts, and components 

installed or included in a vehicle, (2) replacements and improvements to those systems, parts, 

and components, (3) accessories and additions to motor vehicles, and (4) devices or articles with 

an apparent safety-related purpose – is very broad. The status of these items as motor vehicle 

equipment does not depend on the type of technology or its mode of control (mechanical or 

electronic) or whether an item is tangible or intangible. The transition from mechanical to 

electromechanical systems has thus had no significant effect on the extent of NHTSA’s authority 

over motor vehicle performance. NHTSA continues to have regulatory authority under the Safety 

Act over all the systems, parts, and components installed on new motor vehicles, even as motor 

vehicle control systems become increasingly electronic, and perhaps increasingly automated, in 

the future.

 

43 § 30102(a)(7)(C); MAP-21, Pub. L. 112-141, § 31201, 126 Stat. 405. See www.gpo.gov/fdsys/pkg/PLAW112publ141/pdf/PLAW-112publ141.pdf (last accessed Jan. 27, 2014). Congress added subparagraph (C) to the 

statutory definition of “motor vehicle equipment” in 1970 when it amended the definition in order to clarify the 

Department’s authority over additional objects such as motorcycle helmets. See S. Rep. No. 91-559, at 5 (1970). 

However, Congress did not seek to limit the extension of the Department’s authority only to motorcycle helmets and 

instead utilized the broad terms “device, article, and apparel” to describe the universe of objects that are within the 

agency’s authority. See id. Acknowledging the concerns of those who authored the House version of the amendatory 

language that utilizing the terms “device, article, and apparel” might unduly extend the Department’s authority to 

objects that have only a tangential relation to motor vehicle safety, the conference committee added a use restriction. 

See id. Congress relaxed this use restriction in the statutory definition of “motor vehicle equipment” as part of the 

amendments to the Safety Act in MAP-21. See MAP-21, Pub. L. 112-141, § 31201, 126 Stat. 405. Thus, the 

Department’s regulatory authority under subparagraph (C) is limited to those devices, articles, or apparel that are 

used for “the apparent purpose of safeguarding users of motor vehicles against risk of accident, injury, or death.”

See id. (Emphasis added.) 44 49 U.S.C. §§ 30102(a)(6), 30111. 45 49 U.S.C. § 30102(a)(7)(A). 46 49 U.S.C. § 30102(a)(7)(B).
36

Put in the context of V2V-related motor vehicle equipment, NHTSA considers the 

following items subject to the agency’s regulatory authority:

(1) Any integrated original equipment (OE) used for V2V communications or safety 

applications reliant on V2V communications

(2) Any integrated aftermarket equipment used for V2V communications or safety 

applications reliant on V2V communications47

(3) Some non-integrated aftermarket equipment, depending on its nature and apparent 

purpose48

(4) Software that provides or aids V2V functions, and software updates to all of this 

equipment49

(5) Some roadside infrastructure (V2I), to the extent it relates to safety50

We describe the agency’s specific authority over these V2V-related items of motor 

vehicle equipment in more detail below.

1. Integrated OEM V2V technologies

Integrated OE V2V technologies, in this case, refer to all items of equipment that 

function as part of a V2V system and are built into the vehicle when it is produced for sale. As 

explained above, 49 U.S.C. § 30102(a)(7)(A) defines “motor vehicle equipment,” in relevant 

part, as including all systems, parts, and components that are installed in or accompany a motor 

vehicle as it is originally manufactured. Again, “system, part, or component” is broad language 

that encompasses a large universe of items that can be considered motor vehicle equipment.51

 

47 § 30102(a)(7)(B), if the equipment “improves” an already-existing function of the vehicle or is an “addition” to 

the vehicle.

48 § 30102(a)(7)(B), if we interpret the equipment as constituting a motor vehicle “accessory” (something to be used 

while the vehicle is in operation, that enhances that operation), or § 30102(a)(7)(C), if we interpret the equipment as 

constituting a device used for the apparent purpose of traffic safety (purpose would be clearly observable from the 

characteristics of the object and the context of its use, rather than necessarily defined by the manufacturer’s intent 

for the equipment).

49 § 30102(a)(7)(B), because updates can be replacements, improvements. 50 § 30102(a)(7)(B) and (C), if its apparent purpose is safety, it may be an “accessory” or a 

“device...manufactured...with the apparent purpose of safeguarding users of motor vehicles against accident, injury, 

or death.” We note that there will certainly be roadside infrastructure that would not fall within this category. A stop 

sign, for example, may be provided by a municipality for safety reasons, and it may even be manufactured with the 

apparent purpose of safeguarding users of motor vehicles against accident, injury, or death, but NHTSA would not 

consider the stop sign to be motor vehicle equipment. 51 As last accessed in Merriam Webster on Mar. 4, 2014: (1) A system is “a regularly interacting or interdependent 

group of items forming a unified whole . . . : a group of devices or artificial objects or an organization forming a 

network especially for distributing something or serving a common purpose.” See www.merriamwebster.com/dictionary/system ; (2) A part is “one of the often indefinite or unequal subdivisions into which 
37

The agency has already given some consideration to the application of subparagraph (A) 

of the definition of “motor vehicle equipment” to technologies that include both mechanical and 

electromechanical/tangible and intangible aspects. A recent example of such a technology that 

the agency has considered to be an item of motor vehicle equipment is the OnStar in-vehicle 

communications system.

52 OnStar is available on many new General Motors vehicles, and is also 

offered as an aftermarket option for certain other vehicles.53 As an item that is built into the 

vehicle in a way that cannot easily be un-integrated, for the purposes of providing various 

functions such as emergency notification and turn-by-turn navigation, OnStar is considered by 

the agency to be a system, part, or component installed in motor vehicles as originally 

manufactured, when present on the vehicle prior to initial sale. Similarly, DSRC and other

equipment that allow V2V-based safety applications to function would be considered “motor 

vehicle equipment” by virtue of these items being installed in a new motor vehicle at the time of 

manufacture, in the same manner as OnStar.

2. Integrated aftermarket equipment

The broad definition of “motor vehicle equipment” also covers equipment and devices 

purchased by motor vehicle users in the aftermarket, i.e., after the vehicle’s initial sale.54 The 

agency’s jurisdiction over aftermarket equipment is important in regard to V2V-related 

technologies because consumers may be interested in obtaining equipment for their used vehicles 

to give them V2V capabilities and help them be seen by other vehicles on the roads. Further, any 

aftermarket software updates to V2V-related systems or software enabling other devices to 

connect to the V2V system would be considered “motor vehicle equipment” under this part of 

the definition, as discussed further below.

The statutory language in 49 U.S.C. § 30102(a)(7)(B) separates the items covered by this 

part of the definition into two groups: (1) those that are a “replacement or improvement,” and (2) 

those that are an “accessory or addition.” We note that even though these groups are different 

from the criteria that govern NHTSA’s regulation of original motor vehicle equipment in § 

30102(a)(7)(A), both statutory provisions essentially refer to “systems, parts, or components” –

we interpret the additional terms in § 30102(a)(7)(B) simply as describing when the equipment 

becomes part of the vehicle (at some point after first sale, rather than prior to first sale). As all 

parts of a vehicle can need replacement, it does not seem accurate to consider the 

 

something is or is regarded as divided and which together constitute the whole.” See www.merriamwebster.com/dictionary/part?show=0&t=1366224315; and (3) A component is “a constituent part: INGREDIENT.” 

See www.merriam-webster.com/dictionary/component. 52 Letter from Anthony M. Cooke, Chief Counsel, NHTSA to Ashley G. Alley, Office of General Counsel, 

Government Accountability Office (Jul. 19, 2007). See

http://isearch.nhtsa.gov/files/GAO%20telematics%20Sept%2013.htm (last accessed Jan. 27, 2014). 53 See https://www.onstar.com/web/fmv/home?g=1 (last accessed Jan. 27, 2014). 54 49 U.S.C. § 30102(a)(7)(B) (covering replacements, improvements, accessories, and additions).
38

“replacements,” “improvements,” “accessories,” or “additions” in part (B) as a narrower set of 

objects than in part (A). Thus, NHTSA interprets its authority over aftermarket equipment 

installed in used vehicles as at least as comprehensive as its authority over original equipment 

installed in new vehicles.

Items that are considered to be accessories or additions are not necessarily closely related 

to the systems, parts, and components originally installed in new motor vehicles (in the sense 

that these items potentially do not duplicate the functions of original equipment), as a 

“replacement” or “improvement” might be. The dictionary definition of “addition” seems to 

imply that an “addition” to the motor vehicle is an item that becomes united or joined with a 

motor vehicle.55 In other words, it is not an item that can be freely carried into and out of the 

vehicle.

Section III.D.2 describes a wide range of aftermarket V2V equipment items that fall 

within NHTSA’s authority to regulate. Integrated aftermarket V2V equipment is referred to in 

this document as a “retrofit safety device,” and is defined as a V2V system purchased and 

installed in a vehicle after first sale, which can transmit and receive the BSM, run safety 

applications, and provide alerts/warnings to the driver through an in-vehicle display (likely the 

center console DVI). Another noteworthy feature of the RSD is its integration into the vehicle’s 

data bus, so that it can obtain information from the vehicle about the vehicle’s operation in use to 

maximize its effectiveness – such as having access to the vehicle’s actual speed rather than 

attempting to estimate it through GPS coordinates, which helps determine the imminence of a 

potential crash event and could therefore improve timing for need to warn. Thus, the integrated 

aftermarket RSD is scarcely different from the integrated OE V2V system, with similar if not 

identical components, which can either “improve” the vehicle or be an “addition” to it under § 

30102(a)(7)(B). Non-integrated aftermarket V2V equipment (i.e., that which can be removed 

from a vehicle relatively easily, like a navigation-system-type device or a smartphone 

application) will be covered in Section IV.A.3.

3. Non-integrated aftermarket equipment

It is difficult to predict at this point how wide the potential future range of aftermarket 

V2V equipment might be. If we take as an example all of the electronic tools that drivers now 

have at their disposal to aid in navigation, there are integrated OE services like GM’s OnStar 

mentioned above, which is also available for certain vehicles as an aftermarket option; there are 

“dedicated” navigation devices sold by companies like Garmin or TomTom, which can be 

installed in a vehicle simply by mounting it in a cradle and can be as easily removed and 

 

55 As last accessed in Merriam Webster on Jan. 27, 2014: (1) An addition is “a part added (as to a building or 

residential section).” See www.merriam-webster.com/dictionary/addition; and (2) To add means “to join or unite so 

as to bring about an increase or improvement.” See www.merriam-webster.com/dictionary/add.
39

installed in another vehicle; and there are smartphone applications, such as Google Navigation or 

Apple Maps, which use the phone’s GPS (and often a connection to the Internet) to determine 

where a vehicle is and where it needs to go to reach a certain destination, all the while allowing 

full or nearly-full access to all of the phone’s other features. It seems plausible that future 

aftermarket V2V devices will span a similar range of forms and functions. Depending on their 

design and apparent purpose, non-integrated or “nomadic” devices, which can be carried into and 

out of vehicles at the driver’s whim, may still be covered by the Safety Act.

§ 30102(a)(7)(B) and (C) allow the agency to regulate “accessories” as well as “devices 

or articles ... manufactured [or] sold ... with the apparent purpose of safeguarding users of 

motor vehicles against risk of accident, injury, or death.” As with the other portions of the 

definition of motor vehicle equipment, we interpret these words to cover both mechanical and 

electronic “accessories,” “devices,” and “articles.”

The dictionary definition of “accessory” states that an accessory is a secondary item 

which adds some value or function (such as additional convenience or effectiveness) to the 

original item.56 While such a definition does not contemplate that item’s becoming a part of (or 

physically attached to) the motor vehicle in order to be regarded as an accessory (as such an 

interpretation would make “accessory” duplicative of the term “addition”), this definition does 

seem to imply some sort of use of the item in conjunction with the motor vehicle. Thus, an item 

could be an “accessory” under § 30102(a)(7)(B) if a substantial portion of its expected use were 

in conjunction with motor vehicles.

A dedicated handheld aftermarket V2V device would fall comfortably under any of these 

definitions – it could be an “accessory,” or it could be a “device or article...manufactured or sold 

with the apparent purpose of safeguarding users of motor vehicles against risk of accident, 

injury, or death” because a substantial portion of its expected use is reasonably in conjunction 

with a motor vehicle. Moreover, the anticipated basic trait of any V2V device purchased for 

installation in a vehicle is that it emits the BSM, whether or however it provides safety 

information to the driver. Emitting a BSM will necessarily protect the driver from incidents that 

might occur with other V2V-equipped vehicles, which are able to detect the BSM and alert their 

own drivers accordingly. This is fundamentally a safety purpose.

For mobile devices, like a smartphone, a tablet, a tablet computer or other mobile 

platform, in which V2V-enabled applications and related technology are only one of several 

functions, the Safety Act authorizes the agency to regulate the V2V-enabled applications to the 

extent that they are an accessory to a motor vehicle or that they are “manufactured or sold with 

 

56 As last accessed in Merriam Webster on Jan. 27, 2014: (1) An accessory can be “a thing of secondary or 

subordinate importance: ADJUNCT” or “an object or device not essential in itself but adding to the beauty, 

convenience, or effectiveness of something else.” See www.merriam-webster.com/dictionary/accessory.
40

the apparent purpose of safeguarding users of motor vehicles against risk of accident, injury, or 

death.”57 Consider the example of an application that a vehicle owner can download for a 

smartphone to enable the smartphone to transmit and receive BSMs. This application on the 

smartphone could gather information on surrounding vehicles that are transmitting BSMs and

use this information to alert a driver of a potential crash. In this situation, the application is an 

accessory to the motor vehicle (by way of its use with the motor vehicle) and also a “device or 

article manufactured or sold with the apparent purpose of safeguarding users of motor vehicles 

against risk of accident, injury, or death.”

In addition to the software application itself, the performance of safety applications could 

be affected by characteristics of the mobile platform (i.e., hardware) on which they are run.

Hardware attributes such as data processing speed, GPS accuracy, screen size, contrast ratio, 

image resolution, camera resolution, and sound/voice quality could affect the application’s 

ability to perform its safety function. For example, the processor on the mobile platform might 

not have the necessary computational power to process incoming BSMs quickly enough so that a 

warning could be issued to the driver in a timely manner. This possibility could be taken into 

account by establishing criteria for the application to ensure that it could be run only on devices 

with sufficient technical hardware capability to enable the application to function at a level of 

minimum performance necessary for safety. 

The aftermarket V2V device designs examined in this paper that are most likely related to 

future nomadic aftermarket V2V devices include “self-contained” devices, which we assume 

would connect to the vehicle only for a power source (i.e., not connect to the data bus) and 

would both emit/receive a BSM and provide safety applications for the driver, and “vehicle 

awareness devices” or VADs, which simply emit a BSM. Both of these types of devices are 

discussed in more detail in Section III.D.2, and as explained above, fall comfortably within the 

definition of motor vehicle equipment under the Safety Act.

4. Software that aids or updates the V2V system

We discussed above that NHTSA’s Safety Act authority covered not only tangible 

mechanical and electronic motor vehicle equipment, but also reasonably extended to cover 

intangible electronic motor vehicle equipment. Depending on their character, software and 

algorithms that aid or update V2V technologies may be OE, and thus covered under § 

30102(a)(7)(A); or those that are part of aftermarket devices or are updates to either OE or 

 

57 The agency notes that its regulatory authority with respect to mobile devices extends beyond V2V applications 

and technologies. Examples of more general capabilities or features that may cause mobile devices, insofar as they

are used in conjunction with motor vehicles, to fall within the ambit of “motor vehicle equipment” include the 

following: the capability of being paired with a vehicle’s electronics, whether through wired or wireless connection; 

the “driver mode” on unpaired devices; and the capability of the devices and the vehicle to distinguish automatically 

whether a device is located in the driver’s position or a passenger’s position.
41

aftermarket devices, may be covered under § 30102(a)(7)(B) as “replacements,” 

“improvements,” or “additions.” Software could also be an “accessory” as long as a substantial 

portion of its expected use is in conjunction with a motor vehicle. For example, a software 

application that could be installed on a cell phone for the purpose of enabling the phone user to 

perform such vehicle-related functions as starting/stopping or locking/unlocking a motor vehicle 

through manipulating the controls on the phone would be considered an accessory to the motor 

vehicle even if the cell phone itself is not.58 Other applications can perform functions related to 

on-road vehicle operation. An example is a software application that uses the camera function on 

a smartphone placed on a vehicle’s dashboard to detect and recognize vehicles on the road ahead 

and provide forward collision warnings.59 Regardless of where the software is located (i.e., on 

what type of hardware), the software itself would be subject to the Safety Act and could be 

subject to a safety standard or other exercise of NHTSA’s authority (e.g., a recall for a defective 

condition).

5. Roadside infrastructure (V2I)

There are a couple of types of roadside infrastructure that may be involved in facilitating 

DSRC-based V2V, as discussed in Section III.D.3. Communications infrastructure physically 

helps get the messages from the vehicles to and from the SCMS (as at first usage, when the 

 

58 Our conclusion that software can be an item of motor vehicle equipment is reinforced by the recent enactment of 

MAP-21. In that Act, Congress implicitly recognized this fact when it directed NHTSA to examine the need for 

safety standards with regard to electronic systems in passenger motor vehicles. See Pub. L. No. 112-141, §§ 31401-

02, 126 Stat. 405.

Separately, NHTSA is not the only agency that has concluded its statutory authority applies to software. For 

example, the Food and Drug Administration (FDA) has adopted an interpretation of its statutory authority that 

would subject software installed on mobile devices to regulation under the Federal Food, Drug, and Cosmetic Act, 

21 U.S.C. §§ 301 et eq. (2006). See Guidance for Industry and Food and Drug Administration Staff; Mobile Medical 

Applications; Availability, 78 Fed. Reg. 59038 (Sept. 25, 2013) [hereinafter FDA Guidance] (announcing the 

availability of the FDA’s application of the agency’s regulatory authority to software applications installed on 

mobile devices) at www.fda.gov/downloads/MedicalDevices/../UCM263366.pdf (last accessed Feb. 6, 2014). The 

FDA stated that it was issuing the guidance to inform manufacturers, distributors, and other entities about how the 

FDA intends to apply its regulatory authorities to select software applications intended for use on mobile platforms 

(mobile applications or “mobile apps”): Consistent with the FDA’s existing oversight approach that considers 

functionality rather than platform, the FDA intends to apply its regulatory oversight to only those mobile apps that 

are medical devices and whose functionality could pose a risk to a patient’s safety if the mobile app were to not 

function as intended. FDA Guidance, supra. The term “device” is defined in the Federal Food, Drug, and Cosmetic 

Act as:

an instrument, apparatus, implement, machine, contrivance, implant, in vitro reagent, or other similar or 

related article, including any component, part, or accessory, which is . . . recognized in the official National 

Formulary, or the United States Pharmacopeia, or any supplement to them, [ ] intended for use in the 

diagnosis of disease or other conditions, or in the cure, mitigation, treatment, or prevention of disease, in 

man or other animals, and which does not achieve its primary intended purposes through chemical action 

within or on the body of man or other animals and which is not dependent upon being metabolized for the 

achievement of its primary Intended purpose.

21 U.S.C. § 321(h) (2006).

59 E.g., see www.ionroad.com/ (last accessed Jan. 28, 2014).
42

vehicle is self-reporting a malfunction, or when it is reporting on another vehicle’s perceived 

malfunction), and helps get new certificates and the CRL from the SCMS to the V2V-equipped 

fleet. The communications infrastructure includes roadside equipment (RSE) units, which 

contain a DSRC radio or a cellular modem, a processor, connection ports, antennas, and 

software. The RSE uses wireless DSRC to send messages/materials to on-board equipment 

(OBE). The RSE also connects to the SCMS via a wired connection (i.e., through the Internet), 

in order to support the transmission of reports from OBE through the RSE to the SCMS and the 

transmission of certificates from the SCMS through the RSE to the OBE. Security infrastructure 

helps ensure that the messages sent are trustworthy, and helps remove malfunctioning devices

from the system and protect against outside threats. Physically speaking, security infrastructure 

will include computer hardware, software, and a physical location for all of the components of 

the SCMS, which will be connected via the Internet to the RSEs, which then connect to the V2Vequipped vehicles’ OBE.

It could, therefore, end up being important for NHTSA to regulate some aspects of 

infrastructure as a way to avoid regulatory gaps that could critically compromise the overall 

system. Given that certain elements of infrastructure are just as related to safety as on-board 

equipment, and equally intended for safety, the next question becomes how, if possible, to 

regulate that infrastructure. Fitting these infrastructure pieces under NHTSA’s Safety Act 

authority as items of motor vehicle equipment depends on their nature and apparent purpose. If, 

as discussed above, we consider “accessories” as items that are used concurrently with one 

vehicle, then many pieces of roadside infrastructure, which can be used concurrently with many 

vehicles at once, are probably not “accessories.” However, if the apparent purpose of the 

roadside equipment is safety, then it is arguably a device “manufactured ... with the apparent 

purpose of safeguarding users of motor vehicles against risk of accident, injury, or death,” and 

therefore motor vehicle equipment under § 30102(a) (7)(C). For example, an RSE at an 

intersection could provide Signal Phase and Timing information and an intersection map to 

vehicle OBE to support the safety applications that might be triggered to help drivers avoid 

intersection collisions; this would arguably be a safety purpose, even if the RSE could also be 

providing that SPaT information and map for other purposes as well. For that matter, any RSE 

that communicates with vehicles in a way that promotes V2V or V2I communications would 

potentially appear to be doing so for a safety purpose. On the other hand, an RSE that might 

receive data from a vehicle, but cannot communicate with vehicles, would be unlikely to affect 

vehicle safety and, accordingly, would likely not be considered motor vehicle equipment.

Policy Need IV-1 Road Side Equipment Authority

Policy Need: Determination of Authority for NHTSA to regulate Road Side Equipment

Description: NHTSA will thoroughly evaluate the need to regulate aspects of RSE 

operation and assess its authority for doing so.
43

Even if NHTSA decided not to exercise authority directly over roadside infrastructure, 

NHTSA can still significantly influence its design and operation through our Safety Act 

authority to establish safety standards. As will be discussed in more detail below when we 

explain what a V2V system practicable and consistent with our legal authority might include, the 

Safety Act states, among other things, that motor vehicle safety standards must be: (1) 

practicable, (2) meet the need for motor vehicle safety, and (3) be stated in objective terms.60 As 

one hypothetical example, in order to meet the need for motor vehicle safety, a safety standard 

for DSRC-enabled FCW might include provisions to ensure that all messages received from 

other vehicles that could trigger the FCW: (1) Come with some kind of authentication to verify 

message is from a trusted source; and (2) Include provisions covering checking the accuracy of 

the information from the outside source. RSE would need to be interoperable in order to ensure 

that they functioned correctly within the system – meaning that the messages they send have to 

be able to be read by the OBE in order for the OBE to act on it.

Many aspects of the V2V system, then, can qualify as motor vehicle equipment under the 

Safety Act, which means that NHTSA can regulate them and mandate their installation in new 

motor vehicles (as appropriate) per 49 U.S.C. § 30111 (NHTSA may prescribe motor vehicle 

safety standards for motor vehicles and motor vehicle equipment) and § 30102(a)(9) (“motor 

vehicle safety standard” means a minimum standard for motor vehicle or motor vehicle 

equipment performance). For the other parts of the V2V system that NHTSA cannot regulate 

directly under the Safety Act, we can influence how they develop to a significant extent through 

the manner in which we regulate, as in the infrastructure example above.

Under both the Vehicle Safety Act and the Highway Safety Act, NHTSA has other ways 

of affecting the parts of the V2V system that cannot be regulated directly. For example, 49 

U.S.C. § 30182 provides NHTSA authority to enter into contracts, grants, and cooperative 

agreements with a wide range of outside entities to conduct motor vehicle safety research and 

development activities, including activities related to new and emerging technologies.

Separately, the Highway Safety Act (23 U.S.C. § 401 et seq.) authorizes NHTSA to enter into 

contracts, grants, cooperative agreements, and other transactions for research and development 

activities with a similarly wide range of outside entities in “all aspects of highway and traffic 

safety systems ... relating to [ ] vehicle, highway, [and] driver ... characteristics” (§ 403(b)), as 

well as collaborative research and development, on a cost-shared basis, to “encourage innovative 

solutions to highway safety problems” and “stimulate the marketing of new highway safety 

related technology by private industry” (§ 403(c)). Because issues related to V2V are crosscutting, spanning both the Vehicle Safety Act and the Highway Safety Act, these separate 

authorities provide the agency with sufficient flexibility to enter into a variety of agreements 

 

60 49 U.S.C. § 30111(a).
44

related to the development of a V2V security system (although the agency currently lacks 

sufficient appropriations to incur any significant Federal expenditures for these purposes).

A principle of appropriations law known as the “necessary expense doctrine” allows 

NHTSA to take the next step of entering into contracts or agreements to ensure the existence of 

sufficient communications and security systems to support deployment of V2V technologies, if 

V2V communications are mandated or otherwise regulated by a Federal Motor Vehicle Safety 

Standard or other NHTSA regulation. According to that principle, when an appropriation is made 

for a particular purpose, it confers on the receiving agency the authority to incur expenses 

necessary to carry out the purpose of the appropriation.61 Under the necessary expense doctrine, 

the spending agency has reasonable discretion to determine what actions are necessary to carry 

out the authorized agency function. Here, the deployment and operation of the SCMS is 

necessary in order for V2V technology and on-board equipment to function in a safe, secure and 

privacy-protective manner. As designed, V2V technology cannot operate without a sufficient 

security system, and absent such a security system, misbehavior by hackers or others could 

compromise V2V functionality and participant privacy. If the problem of “misbehavior” were 

sufficiently widespread, it might even cause widespread disregard of or delayed response to V2V 

warnings. Hence, a robust SCMS is imperative in the V2V regulatory environment.

For these reasons, in addition to NHTSA’s research, development, and collaboration 

authority under the Vehicle Safety Act and the Highway Safety Act, if the agency issues a V2V 

FMVSS or other V2V-related regulation, the necessary expense doctrine provides sufficient 

authority under the Vehicle Safety Act to take the next step of entering into agreements or 

contracts, either for cost or no-cost, with the goal of ensuring the existence (i.e., the development 

and operation) of sufficient communications and security systems to support the reliability and 

trustworthiness of V2V communications. As is the case under the agency’s research and 

development authority, discussed above, the current limiting factor is the absence of sufficient 

appropriations to incur any significant expenses in this regard.

 

61 Under the necessary expense doctrine, an expenditure is justified if it meets a three-part test: (1) the expenditure 

must bear a logical relationship to the appropriation sought to be charged (i.e., it must make a direct contribution to 

carrying out either a specific appropriation or an authorized agency function for which more general appropriations 

are available); (2) the expenditure must not be prohibited by law; and (3) the expenditure must not be otherwise 

provided for (i.e., it must not be an item that falls within the scope of some other appropriation or statutory funding 

scheme. See U.S. Gen. Accounting Office, Principles of Federal Appropriations Law 4–22 (3d ed.2004) (the “GAO 

Redbook”) at www.gao.gov/special.pubs/3rdeditionvol1.pdf.
45

B. Agency actions that are practicable and consistent With its legal 

authority

1. Elements of the Safety Act that would apply to potential future agency actions

A V2V system, as currently envisioned, is a compilation of many elements. Essentially, 

DSRC units in vehicles send out BSMs to alert other vehicles to their presence and receive 

BSMs from other vehicles in order to determine whether to warn their drivers of impending risk; 

BSMs must be accompanied by security certificates so that the receiving vehicle can trust their 

source; and the receiving vehicle receives the BSM through its DSRC unit and triggers safety 

applications (at this point, we are only discussing applications that would provide warnings), if 

necessary, depending on what the message received indicates about the sending vehicle’s 

behavior. In order for the entire system to function effectively, each vehicle or aftermarket 

device participating in the system may need periodic updates to its security certificates, and may 

need information about vehicles or devices that are malfunctioning or have been otherwise 

compromised (so that they know not to trust the BSMs received from those vehicles or devices).

In addition, the system also needs: (1) An overarching security manager to provide those updates 

and that information; and (2) A communications network to get those updates and information to 

the devices. How, then, would NHTSA exercise its legal authority from a central source to bring 

these elements into existence?

As explained above, NHTSA may establish Federal Motor Vehicle Safety Standards 

(which would be codified in 49 CFR Part 571) for new motor vehicles and motor vehicle 

equipment. NHTSA could establish FMVSSs for DSRC units in vehicles (requiring that all new 

vehicles be equipped with DSRC) and in aftermarket equipment, and also for the safety 

applications enabled by those DSRC units. As part of those FMVSSs, NHTSA could include 

requirements for content of the BSM, content of the security certificates (including how up-todate they need to be), and so on.

NHTSA has general authority to prescribe regulations that help to carry out the duties and 

the powers of the Secretary, including, for example, the overarching purpose of 49 U.S.C. 

Chapter 301, to reduce traffic accidents and deaths and injuries resulting from traffic accidents.62

There are fewer substantive requirements for a non-FMVSS regulation,63 which can be helpful, 

 

62 Under the Safety Act as originally written, NHTSA had express authority to issue, amend, and revoke such rules 

and regulations as deemed necessary to carry out the Safety Act. See Safety Act, Sec. 119, previously codified at 15 

U.S.C. § 1407. That language was not included in the recodification of the Safety Act in 1994, but the Department 

of Transportation Act continues to include similar language, currently codified at 49 U.S.C. § 322, giving the 

Secretary authority to prescribe regulations to carry out the duties and powers of the Secretary, and allowing that 

authority to be delegated.

63 A regulation not promulgated as an FMVSS must still comply with Administrative Procedure Act requirements to 

be reasonable and contain a rational connection between the factual support for the rule and the requirements of the 
46

for example, if the agency is concerned about fulfilling one or some of the requirements 

discussed below for FMVSSs; but the agency also has more enforcement tools available for 

dealing with non-compliance with a safety standard as compared to non-compliance with a nonFMVSS regulation.64 Additionally, the preemptive effect of an FMVSS is clear from the Safety 

Act.

65

We will concentrate the rest of this discussion on the requirements for FMVSSs. A future 

V2V program would likely be more comprehensively successful if DSRC and DSRC-based 

safety applications are required through FMVSSs than if NHTSA issued non-FMVSS 

regulations that merely set out how DSRC must work if provided. Without a requirement that all 

new vehicles be equipped with DSRC, it would likely take far longer for DSRC to penetrate a 

substantial portion of the nation’s vehicle fleet, thus delaying V2V’s benefits and making 

security system needs hard to predict.

Under the Safety Act, NHTSA’s motor vehicle safety standards are generally 

performance-oriented.66 Further, the standards are required to be practicable, objective, and meet 

the need for safety.67 The following section will discuss briefly the meaning of each of these 

requirements, and then explore what the agency might do in order to ensure that safety standards 

for DSRC and DSRC-enabled safety applications reasonably meet those requirements.

a) What does “performance-oriented” mean?

In the Safety Act, the Secretary is directed to issue motor vehicle safety standards.

“Motor vehicle safety standards” are defined as “minimum standard[s] for motor vehicle or 

motor vehicle equipment performance.”68 One point to note at the outset is the party of whom 

performance is required: NHTSA’s safety standards apply to manufacturers of new motor 

 

rule itself, and it must also carry out the powers and duties of the Secretary, by doing things like facilitating the 

agency’s performance of its statutory functions or providing additional assurance that regulated parties will properly 

perform their statutory and regulatory obligations.

64 NHTSA generally has three enforcement tools relevant to standards and regulations: notification and remedy 

(recalls) of noncompliant vehicles (49 U.S.C. §§ 30118, 30119, 30120), injunctions (49 U.S.C. § 30163(a)), and 

civil penalties (49 U.S.C. § 30165). While NHTSA can order recalls and assess civil penalties, only a court can 

order an injunction; additionally, NHTSA’s orders for recalls or civil penalty assessments are themselves 

enforceable only in court.

65 49 U.S.C. § 30103(b). 66 49 U.S.C. § 30102(a)(8) (defining “motor vehicle safety” as “the performance of a motor vehicle . . . in a way that 

protects the public against unreasonable risk of accidents occurring because of the design, construction, or 

performance of a motor vehicle”); and § 30102(a)(9) (defining “motor vehicle safety standard” as “a minimum 

standard for motor vehicle or motor vehicle equipment performance”). See also: S. Rep. No. 89-1301, at 2713-14 

(1966) (stating that motor vehicle standards issued by NHTSA should specify a minimum level of safety 

performance).

67 49 U.S.C. § 30111(a) (establishing requirements for NHTSA to follow when issuing motor vehicle safety 

standards).

68 Id.; see also: § 30102(a)(9) (emphasis added).
47

vehicles and motor vehicle equipment. It therefore falls to those “manufacturers” – from vehicle 

OEMs to OE suppliers to aftermarket device manufacturers to creators of V2V safety 

applications for smartphones – to certify compliance with any safety standards established by 

NHTSA, and to conduct recalls and remedy defects if NHTSA finds them.69 Vehicle owners are 

generally not required to comply with NHTSA’s safety standards, which means that for vehicles 

already on the roads, participation in the V2V system would be entirely voluntary: NHTSA can 

regulate how aftermarket devices function, but it cannot force manufacturers or drivers to add 

them to used vehicles. The one exception to this rule against retrofit is that NHTSA has authority 

to require retrofit of commercial heavy-duty vehicles,70 but that is not part of this research paper 

on light-duty vehicles, and will be examined in more detail in the agency’s decision in 2014 with 

reference to heavy-duty vehicles.

While NHTSA is directed to establish performance standards, the case law and the 

legislative history indicate that when necessary to promote safety, NHTSA can be quite specific 

in drafting its performance standards and may require or preclude the installation of certain 

equipment. The cases have reinforced this concept by determining that NHTSA is “generally 

charged”71 with setting performance standards, instead of becoming directly involved in 

questions of design.72 The legislative history further illustrates that NHTSA’s standards are to 

“[specify] the required minimum safe performance of vehicles but not the manner in which the 

manufacturer is to achieve the specified performance.”73 An example cited in the legislative 

history points to “a building code which specifies the minimum load-carrying characteristics of 

the structural members of a building wall, but leaves the builder free to choose his own materials 

and design.”74 In that example, the agency could require the wall to be built (analogous to 

requiring certain equipment in vehicles) but would be expected to measure the wall’s regulatory 

compliance by its performance rather than its design.

Although the Safety Act directs NHTSA to issue performance standards, however, 

Congress understood that the agency may preclude certain designs through these performance 

standards. “Motor vehicle safety” is defined in the Safety Act as the performance of a motor 

 

69 49 U.S.C. § 30115(a), “Certification of compliance; In general”; § 30116, “Defects and noncompliance found 

before sale to purchaser”; § 30117(a), “Providing information to, and maintaining records on, purchasers; Providing 

information and notice”; § 30118, “Notification of defects and noncompliance”; § 30119, “Notification procedures”; 

§ 30120, “Remedies for defects and noncompliance.” 70 Per 49 CFR 1.95, which delegates to NHTSA the Secretary’s authority under Sec. 101(f) of the Motor Carrier 

Safety Improvement Act of 1999 (Pub. L. 106-159; Dec. 9, 1999) to promulgate safety standards for “commercial 

motor vehicles and equipment subsequent to initial manufacture.” NHTSA’s retrofit authority is coextensive with 

FMCSA’s.

71 Washington v. Dept. of Transp., 84 F.3d 1222, 1224 (10th Cir. 1996) (citations omitted). 72 Id. at 1224 (citations omitted). 73 S. Rep. No. 89-1301, at 2713-14 (1966). 74 Id.
48

vehicle in a way that protects the public from unreasonable risks of accident due to (among other

things) the design of a motor vehicle.75 The legislative history indicates that this language is not 

intended to afford the agency the authority to promulgate design standards, “but merely to clarify 

that the public is to be protected from inherently dangerous designs which conflict with the 

concept of motor vehicle safety.”76 This clarification is evidence that Congress recognized that 

performance standards inevitably have an impact on the design of a motor vehicle.77

The courts have further elaborated on the framework established by Congress and have 

recognized that, when necessary to achieve a safety purpose, NHTSA can be quite specific in 

establishing performance standards even if certain designs will be precluded. For example, the 

Sixth Circuit found that an agency provision permitting rectangular headlamps, but only if they

were of certain specified dimensions, was not an invalid design restriction and “serve[d] to 

ensure proper headlamp performance,” reasoning that “the overall safety and reliability of a 

headlamp system depends to a certain extent upon the wide availability of replacement lamps, 

which in turn depends upon standardization.”78 Thus, the court found it permissible for the 

agency to establish very specific requirements for headlamps even though it would restrict 

design flexibility.79

Further, the cases indicate that NHTSA can establish standards to require the installation 

of certain specific equipment on vehicles and establish performance standards for that 

equipment. For example, the Tenth Circuit found in Washington v. DOT that “NHTSA’s 

regulatory authority extends beyond the performance of motor vehicles per se, to particular items 

of equipment.”80 In that case, the validity of NHTSA’s FMVSS No. 121 requiring ABS systems 

on air-braked vehicles was challenged as “imposing design specifications rather than 

performance criteria.”81 The court’s conclusion was based not only on the fact that prior courts 

had upheld NHTSA’s standards requiring particular equipment,82 but also on the fact that 

 

75 § 30102(a)(9). 76 H.R. Rep. No. 89-1919, at 2732 (1966). 77 Courts have also recognized this fact. See Chrysler Corp. v. Dept. of Transp., 515 F.2d 1053, 1058-59 (6th Cir. 

1975); see also: Washington, 84 F.3d at 1224 (stating “the performance-design distinction is much easier to state in 

the abstract than to apply definitively-so .... . This is particularly true when, due to contingent relationships between 

performance requirements and design options, specification of the former effectively entails, or severely constrains, 

the latter.”).

78 Chrysler Corp., 515 F.2d at 1058-59. 79 Id. 80 Washington, 84 F.3d at 1222, 1225 (citations omitted). 81 Id. at 1223. 82 Id. at 1225 (citing Chrysler Corp. v. Rhodes, 416 F.2d 319, 322, 322 n. 4) (1st Cir. 1969) (“motor vehicles are 

required to have specific items of equipment . . . These enumerated items of equipment are subject to specific 

performance standards,” including lamps and reflective devices requiring “specific items of equipment”)); Wood v. 

Gen. Motors Corp., 865 F.2d 395, 417 (1st Cir. 1988) (“requiring seat belts or passive restraints . . . has elements of 
49

Congress had recognized NHTSA’s former rulemakings and left NHTSA’s authority unchanged 

when it codified the Safety Act in 1994.

Thus, in summary, NHTSA is required to issue performance standards when regulating 

motor vehicles and motor vehicle equipment. However, NHTSA is able to be quite specific in 

establishing performance standards and may preclude certain designs that are contrary to the 

interests of safety. Further, NHTSA may require the installation of certain equipment and 

establish performance standards for that equipment.

b) Standards “meeting the need for motor vehicle safety”

As required by the Safety Act, standards issued by the agency must “meet the need for 

motor vehicle safety.”83 As “motor vehicle safety” is defined in the statute as protecting the 

public against “unreasonable risk” of accidents, death, or injury,84 the case law indicates that 

there must be a nexus between the safety problem and the standard.85

However, a standard need not address safety by direct means. In upholding NHTSA’s 

authority to issue a safety standard requiring standardized vehicle identification numbers, the 

Fourth Circuit Court of Appeals found that an FMVSS requiring VINs met the need for motor 

vehicle safety by such indirect means as reducing errors in compiling statistical data on motor 

vehicle crashes (in order to aid research to understand current safety problems and support future 

standards, to increase the efficiency of vehicle recall campaigns, and to assist in tracing stolen 

vehicles).86

c) “Objective” standards

A standard is objective if it specifies test procedures that are “capable of producing 

identical results when test conditions are exactly duplicated” and performance requirements 

whose satisfaction is “based upon the readings obtained from measuring instruments as opposed 

to subjective opinions.”87 The requirement that standards be stated in objective terms matches 

 

a design standard”); Automotive Parts & Accessories Ass’n v. Boyd, 407 F.2d 330, 332 (D.C. Cir. 1968) (“factor 

equipped . . . head restraints which meet specific Federal standards”). 83 49 U.S.C. § 30111(a). 84 49 U.S.C. § 30102(a)(8). 85 e.g.,: National Tire Dealers Ass’n v. Brinegar, 491 F.2d 31, 35-37 (D.C. Cir. 1974) (stating that the administrative 

record did not support a significant nexus between motor vehicle safety and requiring retread tires to have 

permanent labels because there was no showing that a second-hand owner would be dependent on these labels and 

no showing as to how often such situations would arise); See also H&H Tire Co. v. Dept. of Transp., 471 F.2d 350, 

354-55 (7th Cir. 1972) (expressing doubt that the standard met the need for safety because there was little evidence 

that the required compliance tests would ensure that retreaded tires would be capable of performing safely under 

modern driving conditions).

86 Vehicle Equip. Safety Comm’n v. NHTSA, 611 F.2d 53, 54 (4th Cir. 1979). 87 Chrysler Corp. v. Dept. of Transp., 472 F.2d 659, 676. See also Paccar, Inc., v. Nat’l Highway Traffic Safety 

Admin., 573 F.2d 632, 644 (9th Cir. 1978).
50

the overall statutory scheme requiring that manufacturers self-certify that their motor vehicles or 

motor vehicle equipment comply with the relevant FMVSSs.88 In order for this statutory scheme 

to work, the agency and the manufacturer must be able to obtain the same result from identical 

tests in order to objectively determine the validity of the manufacturer’s certification.89

Using those two elements of objectivity (capable of producing identical results and 

compliance based on measurements rather than subjective opinion), the Sixth Circuit Court of 

Appeals found that the test procedure in question in an early version of FMVSS No. 208 was not 

objective because the test dummy specified in the standard for use in compliance testing did not 

give consistent and repeatable results.90 The court in this case was unconvinced that the standard 

met the objectivity requirements even though NHTSA based its test procedure on a test dummy 

in a voluntary automotive industry standard (Society of Automotive Engineers Recommended 

Practice J963). The court rejected NHTSA’s explanation that, although J963 “may not provide 

totally reproducible results,” “dummies conforming to the SAE specifications are the most 

complete and satisfactory ones presently available.”91 Further, the court rejected NHTSA’s 

reasoning that, in the event that the agency’s test results were different from those of the 

manufacturers because of the difference in the test dummies, NHTSA’s test results would not be 

used to find non-compliance, stating that “there is no room for an [ ] agency investigation [ ] in 

this procedure” that enable the agency to compare results of differing tests.92

Other courts have also reached similar conclusions. The Ninth Circuit Court of Appeals, 

relying on the same reasoning adopted by the Sixth Circuit, found that a compliance road test 

specifying the use of surfaces specifically rated with quantifiable numbers (defining the 

“slickness” of the surfaces) was objective despite “[t]he fact that it is difficult to create and 

thereafter maintain a road surface with a particular coefficient of friction does not render the 

 

88 49 U.S.C. § 30115(a). 89 Chrysler Corp., 472 F.2d at 675. 90 As the court stated,

The record supports the conclusions that the test procedures and the test device specified . . . are not 

objective in at least the following respects: (1) the absence of an adequate flexibility criteria for the 

dummy’s neck; the existing specifications permit the neck to be very stiff, or very flexible, or somewhere 

in between, significantly affecting the resultant forces measured on the dummy’s head. (2) Permissible 

variations in the test procedure for determining thorax dynamic spring rate (force deflection characteristics 

on the dummy’s chest) permit considerable latitude in chest construction which could produce wide 

variations in maximum chest deceleration between two different dummies, each of which meets the literal 

requirements of SAE J963. (3) The absence of specific, objective specifications for construction of the 

dummy’s head permits significant variation in forces imparted to the accelerometer by which performance 

is to be measured.

Id. at 676-78. 91 Id. at 677. 92 Id. at 677-79.
51

specified coefficient any less objective.”93 In this case, both NHTSA and the manufacturer 

would perform road tests on surfaces with identically rated friction coefficients.94 In a later case, 

the Sixth Circuit upheld NHTSA’s decision not to incorporate a test suggested by a commenter 

for wheelchair crashworthiness performed with a “test seat” that “shall be capable of resisting 

significant deformation” during a test as not sufficiently objective.95 In the absence of language 

quantifying how much deformation is significant, terms such as “significant deformation” do not 

provide enough specificity to remove the subjective element from the compliance determination 

process.

d) “Practicable” standards

In general, the practicability of a given standard involves a number of considerations. The 

majority of issues concerning the practicability of a standard arise out of whether the standard is 

technologically and economically feasible. An additional issue is whether the means used by 

manufacturers to comply with a standard will be accepted and correctly used by the public.

e) “Technologically practicable” standards

Significant technical uncertainties in meeting a standard might lead a court to find that a 

standard is not practicable. For example, the Sixth Circuit Court of Appeals upheld NHTSA’s 

decision to amend FMVSS No. 222 to include requirements for wheelchair securement and 

occupant restraint on school buses with a static96 compliance test instead of a dynamic test,97

noting that the administrative record showed that this particular dynamic test was 

underdeveloped and had many unresolved technical problems.98 The court noted that it is not 

 

93 Paccar, Inc. v. Nat’l Highway Traffic Safety Admin., 573 F.2d 632, 644 (9th Cir. 1978), cert. denied, 439 U.S. 862 

(1978).

94 Id. (stating that the “skid number method of testing braking capacity meets the [objectivity] definition. Identical 

results will ensue when test conditions are exactly duplicated. The procedure is rational and decisively 

demonstrable. Compliance is based on objective measures of stopping distances rather than on the subjective 

opinions of human beings.”).

95 Simms v. Nat’l Highway Traffic Safety Admin., 45 F.3d 999, 1007-08 (6th Cir. 1995). 96 Static testing tests the strength of individual components of the wheelchair separately, while dynamic testing 

subjects the entire wheelchair to simulated real-world crash conditions. See Simms, 45 F.3d at 1001. 97 Id. at 1006-08. Petitioners argued that NHTSA had acted unlawfully in promulgating standards for the securement 

of wheelchairs on school buses based only on “static” instead of “dynamic” testing. Id. Static testing tests the 

strength of the individual components of a securement device. Id. Dynamic testing is a full systems approach that 

measures the forces experienced by a human surrogate (test dummy) in a simulated crash that replicates real-world 

conditions and assesses the combined performance of the vehicle and the securement device. Id. 98 Id. at 1005-07. NHTSA agreed that dynamic testing is the preferred approach (because it more fully and 

accurately represents the real-world conditions in which the desired safety performance is to be provided), but 

explained that it was not practicable at that time to adopt dynamic testing because there was:

(1) [N]eed to develop an appropriate test dummy; (2) need to identify human tolerance levels for a 

handicapped child; (3) need to establish test conditions; (4) need to select a “standard” or surrogate 

wheelchair; (5) need to establish procedures for placing the wheelchair and test dummy in an effective test 
52

practicable “[t]o attempt to fashion rules in an area in which many technical problems have been 

identified and no consensus exists for their resolution .... .”99 In another example, the Ninth 

Circuit Court of Appeals found a compliance test procedure using a specified friction (slickness)

coefficient to be impracticable due to technical difficulties in maintaining the specific slickness 

test condition. As mentioned above, the Ninth Circuit found the specified coefficient test 

condition to be objective.100 However, simply being objective did not also make the test 

condition practicable. Thus, the cases show that when significant technical uncertainties and 

difficulties exist in a standard promulgated by NHTSA, those portions of the standard can be 

considered impracticable under the Safety Act.

However, the requirement that a standard be technologically feasible does not include the 

additional requirement that the agency show that the technology to be used to comply with the

standard is already fully developed and tested at the time that the standard is promulgated. The 

Sixth Circuit upheld a NHTSA standard requiring “Complete Passive Protection,” that required 

the installation of airbags as standard equipment, by a future date, rejecting petitioner’s 

contention that NHTSA may only establish performance requirements which can be met with 

devices which, at the time of the rulemaking, are developed to the point that they may be readily 

installed.

101 Relying on the legislative history of the Safety Act, the court found that the agency 

“is empowered to issue safety standards which require improvements in existing technology or 

which require the development of new technology, and is not limited to issuing standards based 

fully on devices already developed.”102 Thus, the requirement that standards be technologically

feasible is sufficiently broad that it can be satisfied by showing that new technology can be 

developed in time to comply with the effective date of the standard. A corollary of the agency’s 

authority to issue technology-driving standards is that the agency can rely on data other than 

 

condition; and (6) need to develop an appropriate test buck to represent a portion of the school bus body for 

securement and anchorages.

Id. at 1005. 99 Id. at 1010-11. 100 Paccar, Inc. v. Nat’l Highway Traffic Safety Admin., 573 F.2d 632, 644 (9th Cir. 1978). 101 See Chrysler Corp. v. Dept. of Transp., 472 F.2d 659, 666, 671-75 (6th Cir. 1972). Stages one and two required 

vehicle manufacturers to provide “Complete Passive Protection” or one of two other options on vehicles 

manufactured between January 1, 1972 and August 14, 1973 (for stage one) and after August 15, 1973 (stage two). 

See id. at 666-67. Stage three, requiring solely “Complete Passive Protection,” was required by August 15, 1975. Id.

at 667.

102 Id. at 673. In making its decision, the court stated

[I]t is clear from the Act and its legislative history that the Agency may issue standards requiring future 

levels of motor vehicle performance which manufacturers could not meet unless they diverted more of the 

ir resources to producing additional safety technology than they might otherwise do. This distinction is one 

committed to the Agency’s discretion, and any hardships which might result from the adoption of a 

standard requiring . . . a great degree of developmental research, can be ameliorated by the Agency under . . 

. The section [that] allows the Secretary to extend the effective date beyond the usual statutory maximum of 

one year from the date of issuance, as he has done [here].

Id. at 673.
53

real-world crash data in justifying those standards. Technology that is not yet either fully 

developed or being installed on production vehicles cannot generate real-world performance 

data. Thus, in justifying the issuance of technology-driving standards, it is permissible, even 

necessary, for the agency to rely on analyses using experimental test data or other types of nonreal world performance information in determining whether such standards “meet the need for 

vehicle safety.”

f) “Economically practicable” standards

A standard can be considered impracticable by the courts due to economic infeasibility.

This consideration primarily involves the costs imposed by a standard.103 In the instances in 

which a court has been called upon to assess whether a standard is economically feasible, 

typically with respect to an industry composed largely of relatively small businesses, the courts 

have asked whether or not the cost would be so prohibitive that it could cause significant harm to 

a well-established industry. In essence, this consideration generally establishes a non-quantified 

outer limit of the costs that can be reasonably imposed on regulated entities. If compliance with 

the standard is so burdensome, i.e., costly, so as to create a significant harm to a well-established 

industry, courts have generally found that the standard is impracticable in its application to that 

industry.

g) Standards that encourage “public acceptance and use”

Finally, a standard might not be considered practicable if the public were not expected to 

accept and correctly use the technologies installed in compliance with the standard. When 

considering passive restraints such as automatic seatbelts, the D.C. Circuit stated that “the 

agency cannot fulfill its statutory responsibility [in regard to practicability] unless it considers 

popular reaction.”104 While the agency argued in that case that public acceptance is not one of 

the statutory criteria that the agency must apply, the court disagreed. The court reasoned that 

“without public cooperation there can be no assurance that a safety system can ‘meet the need for 

motor vehicle safety.’”105 Thus, as a part of the agency’s considerations, a standard issued by the 

agency will not be considered practicable if the technologies installed pursuant to the standard 

are so unpopular that there is no assurance of sufficient public cooperation to meet the safety 

need that the standard seeks to address.106

 

103 E.g., Nat’l Truck Equip. Ass’n v. Nat’l Highway Traffic Safety Admin., 919 F.2d 1148, 1153-54 (6th Cir. 1990); 

Ctr. for Auto Safety v. Peck, 751 F.2d 1336, 1343 (D.C. Cir. 1985) (panel opinion by Circuit Judge Scalia). 104 Pac. Legal Found. v. Dept. of Transp., 593 F.2d 1338, 1345-46 (D.C. Cir.), cert. denied, 444 U.S. 830 (1979). 105 Id. 106 Pursuant to concerns about public acceptance of various seat belt designs, NHTSA issued a final rule in 1981 

adding seat belt comfort and convenience requirements to Standard No. 208, Occupant Crash Protection. Federal 

Motor Vehicle Safety Standards; Improvement of Seat Belt Assemblies, 46 Fed. Reg. 2064 (Jan. 8, 1981) (codified 

at 49 CFR Part 571).
54

The discussion in this section thus far has presented the requirements under the Safety 

Act for establishing motor vehicle and motor vehicle equipment safety standards; the following 

discussion will cover how theoretical safety standards for DSRC and DSRC-based safety 

applications might go about fulfilling those requirements.

2. Safety standards for DSRC

NHTSA would theoretically establish an FMVSS for DSRC in order to enable safety 

applications such as IMA, FCW, LTA, DNPW, and others. As discussed above, we are assuming 

here that the FMVSS for DSRC would require DSRC equipment in all new vehicles. For 

purposes of this discussion, we assume that DSRC would have its own FMVSS rather than have 

all of its requirements incorporated into FMVSSs for DSRC-based safety applications – this 

would appear to be preferable to avoid duplication of requirements if multiple safety applications 

were going to be DSRC-based – although any or all of these FMVSSs could certainly be 

established simultaneously. This would also permit OEMs to comply with at least some of the 

safety application FMVSSs using non-V2V technology (e.g., sensor-based FCW technology).

An FMVSS for DSRC must include minimum standards for DSRC performance. This 

requires a determination of what tasks DSRC must be able to perform. NHTSA has certain 

performance measures already available as developed for the Safety Pilot,107 and is also currently 

working to develop a comprehensive list of DSRC use cases as a basis for developing 

performance measures that may be more appropriate for an eventual FMVSS, but at its most 

basic, the DSRC likely must be capable, among other things, of sending and receiving BSMs to 

other vehicles and to infrastructure; of not sending or receiving certain types of information that 

might be harmful to the vehicle or to the V2V system (including BSMs, if the system recognizes 

or the DSRC recognizes itself to be somehow compromised); and of receiving new certificates 

and software updates. Each of those tasks, in turn, has sub-tasks in order to ensure effective 

performance. For example, when a DSRC unit sends out a BSM, the BSM needs to:

• Contain the relevant elements and describe them accurately (e.g., vehicle speed; GPS 

position; vehicle heading; DSRC message ID, etc.);

• Be received quickly enough for the receiving DSRC unit to interpret the message and 

respond accordingly by triggering safety applications or not;

• Contain something to indicate that it should be trusted by the receiving DSRC unit 

and that the message has not altered (e.g., a signed security certificate that is up-todate).

 

107 E.g., System Requirements Description, 5.9 GHz DSRC Vehicle Awareness Device Specification, Version 3.6 

(Jan. 25, 2012) at www.its.dot.gov/newsletter/VAD%20Specs.pdf (last accessed Jan. 28, 2014).
55

In the interest of brevity, this discussion does not contain every current anticipated task 

and sub-task that would likely be included among minimum standards for DSRC performance –

those can be found in Section V.E. For purposes of helping to ensure legal sufficiency, relevant 

tasks must be identified and minimum standards for DSRC units performing those tasks must be 

specified. SAE J2945.1, developed in large part through DOT funds, contains minimum 

performance requirements for BSM communication, but SAE has not yet developed any 

requirements for message accuracy, test procedures, or how the data and message would be used 

(such as message transmission rate or optional data usage in various situations), nor is it certain 

that they will do so in the future. DOT and its research partners have developed performance 

requirements for the BSM and DSRC to use in the Safety Pilot108 that the agency believes are 

adequate for that purpose. SAE has yet to incorporate any of this work, however, in order to 

develop comprehensive voluntary consensus standards that NHTSA could consider to ensure full 

DSRC interoperability.109 SAE’s work is still ongoing, but it is likely reasonable to assume that it 

would be completed prior to a potential future proposal to establish an FMVSS for DSRC. In 

order to determine the performance requirements for the BSM and DSRC that would be needed 

to support interoperability on a larger scale, NHTSA will likely rely on the results of the Safety 

Pilot and other ongoing research, and examine whatever voluntary consensus standards are 

available at that time and seem applicable. Section V.E discusses the status of the voluntary 

consensus standards under development that are relevant to DSRC.

A future DSRC standard may also need to include requirements to ensure that messages 

are able to be received even as more vehicles and infrastructure are broadcasting more often –

“message congestion” has not come up in the Model Deployment due to the relatively low 

density of DSRC-equipped vehicles and infrastructure in Ann Arbor, but may become an issue 

going forward, especially in heavily populated areas. DOT is sponsoring research to evaluate the 

capacity of the spectrum and mitigate the effects of channel congestion on DSRC performance; 

CAMP has also conducted testing, but has been unable to create a situation of channel 

saturation.110 Depending on the findings of that research, the agency may want to consider 

requiring manufacturers to use a particular congestion mitigation algorithm so that the safety 

applications can continue to work as the broadcast channel approaches capacity. As discussed 

above, the case law reasonably supports the agency specifying certain design aspects if necessary 

to ensure proper operation of safety systems.

 

108 Please see: System Requirements Description, 5.9 GHz DSRC Vehicle Awareness Device Specification, Version 

3.6 (Jan. 25, 2012) at www.its.dot.gov/newsletter/VAD%20Specs.pdf (last accessed Jan. 28, 2014) and System 

Requirements Description, 5.9 GHz DSRC Vehicle Awareness Device Specification, Version 3.6 (Dec.26, 2011) at

www.its.dot.gov/meetings/pdf/T2-05_ASD_Device_Design_Specification_20120109.pdf (last accessed Feb. 20, 

2014).

109 See http://standards.sae.org/wip/j2945/ (last accessed Jan. 28, 2014). 110For more information, see Section V.E.1.c). 
56

A safety standard for DSRC also needs to meet the need for safety, which means, as 

discussed above, that there needs to be some nexus between DSRC and the safety problem that a 

DSRC standard is trying to resolve, but does not mean that DSRC must directly create more 

safety itself, as long as it is enabling other safety applications. On the second point, the case law 

supports this view – if VINs could be upheld as meeting the need for motor vehicle safety simply 

by virtue of the fact that they aid research in understanding safety problems and supporting 

future standards, as well as aiding recall campaigns and tracking of stolen vehicles, then DSRC, 

which would directly enable half a dozen safety applications at its inception and perhaps many 

more eventually, seems even more likely to meet the need for safety in that respect.

If the agency decides to issue an FMVSS, we will want to be sure to explain carefully the 

nexus between DSRC and the safety problems that we are trying to address, depending on the 

order in which the agency issues FMVSSs for safety applications. There is no doubt that there is 

a nexus – DSRC can enable all of the safety applications under consideration by the agency, 

which means that DSRC can help to address the safety problems of, e.g., intersection collisions, 

collisions with forward stopped or slowing vehicles, collisions that occur because a driver chose 

to pass a forward vehicle without enough room to do so safely, etc. As far as we know currently, 

DSRC is the only technology that can enable Intersection Movement Assist, Left Turn Assist, 

and Electronic Emergency Brake Light. For some of the other safety applications, which can also 

be enabled by other technologies besides DSRC, such as on-board sensors, radar, or cameras, 

DSRC can add robustness to an on-board system. The agency may nonetheless want to develop 

evidence that a DSRC mandate represents a reasonable technological solution for addressing the 

safety problems at issue. In sum, DSRC will either be the sole enabler of some safety 

applications or present a possible enhancement to on-board systems with regard to other

applications. In either case, DSRC will address safety needs.

A DSRC standard also needs to be objective. It is likely to be objective, according to the 

case law, if exact duplication of test conditions yields identical results, and if compliance is 

based on measurements rather than on subjective opinion. As explained above, while there are 

test procedures for DSRC performance that were used in the Safety Pilot,111 test procedures for 

DSRC performance, survivability, etc. that might be appropriate for an FMVSS have yet to be 

developed, and research continues. Testing for DSRC will likely require procedures to establish 

both that the DSRC unit itself is able to receive and transmit the needed messages as timely as 

needed and without being compromised (recognizing that in the current design, one radio will be 

used exclusively for sending and receiving BSMs, while the other will be used to communicate 

with infrastructure and the security system), and that the BSM elements are accurate. Some 

 

111 E.g., Safety Pilot Model Deployment, Deliverable: Interoperability Stage II Test Report, Task 5. See Docket No. 

NHTSA-2014-0022
57

examples of tests that could be needed for DSRC message transmission/reception might include 

tests for:

• Range,

• Latency,

• Ability to transmit,

• Ability to receive,

• Accuracy of GPS,

• Accuracy of information on vehicle speed and heading, and

• BSM performance in a degraded state when GPS is not available.

Some examples of tests that could help to determine the accuracy of the BSM elements 

might include, among other things:

• Sending an instrumented vehicle through a set of maneuvers and checking whether 

the BSM is reporting vehicle conditions/activity consistently with what the 

instruments are reporting;

• Setting up an array of DSRC receivers at a certain distance from the vehicle to test the 

directional range of the vehicle’s broadcast capability;

• Sending a vehicle through a set of maneuvers and checking whether BSMs from that 

vehicle are received with the required frequency to support particular safety 

applications; and

• Checking the vehicle’s relative reported GPS position against a GPS receiver with a 

known bias to determine the accuracy of the vehicle’s reported relative position.

The agency will have to carefully assess any compliance test that tests the accuracy of 

GPS to ensure that the test is objective. As one example, atmospheric conditions influence the 

accuracy of GPS receivers and can cause the same receiver to produce different results, even 

when the receiver is tested at different times on the same day. Atmospheric and weather 

conditions also influence the range of radio broadcast capabilities. The agency could adjust the 

tolerances of the compliance tests to account for factors like this that introduce uncertainty, but 

this strategy could end up reducing the stringency of the requirements. We also know that there 

are conditions under which the GPS will not be able to work, such under bridges and in “urban 

canyons” that exist between tall buildings in urban and city environments. Compliance tests will 

need to account for these situations, and we are researching methods to compensate for these 

degradations in performance. These examples help to illustrate the uncertainty that exists in 

trying to assess the objectivity of potential compliance tests at this time.

And finally, a DSRC FMVSS would need to be practicable – as defined by technological 

practicability, economic practicability, and public acceptance of the technology.
58

Technologically, DSRC has existed for over a decade, and is currently being used in Japan to 

support V2I applications and electronic toll collection. While DSRC may be widely used for 

some purposes and in some regions, however, ensuring interoperability between vehicles 

remains an issue needing further research. While comprehensive DSRC performance 

requirements and test procedures, such as those that would be included in an FMVSS, have yet to 

be established, it seems reasonably likely that an FMVSS would be technologically practicable 

assuming that objective tests to ensure interoperability are developed.

In terms of economic practicability, NHTSA currently assumes that the cost of a DSRC 

standard would include costs for device hardware and software, as well as costs for the security 

and communications system that would be necessary in order for DSRC to function properly. As 

discussed in Section XI, we estimate the likely total cost for a V2V system to the consumer 

(vehicle equipment costs, fuel economy impact, SCMS costs, and communication costs) at

approximately $341- $350 (7% to 3% discount rate) per new vehicle in 2020. Economic 

practicability requires that compliance with the standard should not be so burdensome as to 

create a significant harm to a well-established industry. It does not seem likely that a court would 

find the standards economically impracticable either for the auto industry, or for any small 

business interests potentially implicated, since those would more likely be in the context of 

aftermarket devices (phone apps and so forth), which are entirely voluntary and do not represent 

a mandate.

For the question of public acceptance, the main concerns with regard to a DSRC FMVSS 

likely relate to security and privacy. In order to avoid risk that a DSRC standard is not accepted 

by the public, the standard could likely benefit from security and privacy requirements for 

message transmission/receipt – for example, that the message does not contain information that 

could create an unreasonable privacy risk; that the unit is resistant to tampering, hacking; etc.

Another requirement related to security that could create public acceptance issues is when and 

how updates to the DSRC occur. DSRC units will likely need periodic software upgrades and 

patches, and may need additional security certificates to be uploaded over the course of their 

lifetimes. If driver action is needed to make those updates successful – for example, if the driver 

must take the vehicle to a dealership for the work to be done – it is possible that some drivers 

simply will forgo the effort, leaving themselves less safe and possibly impairing the entire V2V 

system. NHTSA could try to develop driver alerts as part of a potential FMVSS to help ensure 

that drivers take that action, but would have to consider how to balance the need to warn drivers 

against possible public acceptance issues. At this point, NHTSA is optimistic that updates will be 

able to be performed automatically. Section V.E.4 provides additional discussion on how device 

updates could be managed so that this can be avoided, but the agency will continue to research 

this issue going forward.
59

Policy Need IV-2 V2V Device Software Updates

Policy Need: V2V Device Software Updates

Description: V2V device software updates may be required over its lifecycle. NHTSA 

will need to determine how to ensure necessary V2V device software 

updates are seamless for consumers and confirmed. V2V devices may 

become inoperable over time or potentially out of date with system needs 

as upgrades are implemented. One possible route to address this issue is 

via terms of use required by the SCMS in connection with providing 

security services necessary to support V2V communications.

Excessive false warnings may create another public acceptance issue, in that they may 

annoy drivers and cause them to ignore true warnings if false warnings are too numerous. False 

warnings may be caused through inaccuracies in a vehicle’s reported position, speed or predicted 

path information: preventing these false warnings will require test procedures to reduce these 

inaccuracies and mitigation techniques have already been implemented in the Safety Pilot Model 

Deployment to minimize false positives discovered thus far. Initial analysis of data collected 

during the second phase of Model Deployment indicates that the false positive mitigation 

techniques associated with the IMA safety application has reduced the amount of certain false 

positive alerts observed in the Model Deployment. Additionally, consumer acceptance and 

practicability of the system is currently dependent on the existence of a security system. If the 

agency is not able to identify an entity to manage the security system, then that may affect the 

practicability of any FMVSS mandating DSRC-based V2V, as the security system is currently 

needed to ensure that messages are trustworthy.

3. Safety standards for DSRC-enabled safety applications

As discussed in more detail in Section VI, the agency is currently investigating six safety 

applications that could be enabled by DSRC: IMA, FCW, DNPW, EEBL, BSW/LCW, and LTA.

We may decide to mandate some or all of these applications, and perhaps also future applications 

yet to be developed. If we do mandate them, it seems likely that (1) in the interests of stronger 

enforcement options, they would be incorporated into NHTSA’s regulations as an FMVSS, and 

(2) in the interests of clarity, each would have its own FMVSS. An FMVSS for each of these 

safety applications must include minimum standards for its performance. This first requires a 

determination of what tasks the safety applications need to perform, which varies based on the 

types of safety risks/crash scenarios that the application is intended to address. As further 

discussed in Section VI, the agency is examining the currently available (research-stage) 

performance and test metrics associated with each application. Further, the agency is analyzing 

these metrics against the available safety data to determine whether these metrics cover the 

applicable safety problem. We envision that each FMVSS for one of these safety applications 
60

would set performance requirements that could be met by any technology. For example, FCW 

might be met through use of radar or cameras, or through use of DSRC. However, if DSRC 

performance requirements made it reasonable to require more robust performance, we could 

require that performance when DSRC is mandated. As discussed above, for some applications, 

like IMA, performance requirements can likely be met only with DSRC-based technologies due 

to their ability to detect crossing-path vehicles, but for others, a variety of technologies could 

potentially be used.

It would seem clear-cut that FMVSSs for the V2V safety applications meet the need for 

safety, insofar as we would issue them to address safety problems that continue to cause crashes 

in the absence of regulation or market forces driving their adoption. The safety applications are 

clearly intended to relate to safety – they warn drivers of dangerous conditions and are intended 

to promote safety by triggering a response to avoid the danger.

There are several things that the agency could do to help solidify the nexus of safety 

application warning and driver response. For example, from a technological perspective, research 

continues at this point to develop driver-vehicle interfaces for each of the safety applications. We 

will need to be able to demonstrate how effective the DVIs we may eventually mandate are at 

warning the drivers and inducing them to avoid the dangerous situation. We currently have 

reason to believe that the V2V safety applications will meet the need for safety, but our evidence 

needs to be stronger.

FMVSSs for V2V safety applications also need to be objective, meaning that they specify 

test procedures that are “capable of producing identical results when test conditions are exactly 

duplicated” (meaning that the agency and the manufacturer must be able to obtain the same 

result from identical tests) and performance requirements whose satisfaction is “based upon the 

readings obtained from measuring instruments as opposed to subjective opinions.” As discussed 

above, test procedures and performance requirements for the V2V safety applications are still 

being developed, but NHTSA would ensure that any test procedures it may require would meet 

the criteria of being objective. 

In terms of technological practicability, because test procedures and requirements 

(including those for DVIs) are still being developed for the V2V safety applications, it could be 

advisable to provide additional lead time to meet eventual standards in order to ensure that 

manufacturers have the opportunity to work out how to comply depending on timing for a future
61

potential regulatory action.

112 More research will be helpful in informing future assessments of 

technological practicability.

In terms of economic practicability, NHTSA currently assumes using preliminary cost 

estimates that the cost of standards for the V2V-based safety applications would primarily 

include costs for software that would be used by the vehicle to interpret DSRC signals and make 

decisions about whether to warn the driver, as well as costs for any hardware that would be 

necessary to make those warnings happen via the DVI. As discussed above, it seems unlikely 

that economic practicability would be an issue for potential safety application FMVSSs, but 

more research to determine costs more precisely would be beneficial to this assessment.

Based on the research we have so far from the Safety Pilot, driver enthusiasm for the 

V2V safety applications appears mixed – see Section VII for more information. Given that DVI 

requirements remain under development, and given that the algorithms currently being analyzed 

as part of the Model Deployment have a relatively high false positive rate, more work needs to 

be done before we can be confident that eventual FMVSSs for V2V safety applications will not 

have public acceptance risks.

The discussion in this section has focused so far on what it would take to establish 

FMVSSs to facilitate a V2V system, but a V2V system is not complete without communications 

and security components that NHTSA cannot mandate fully under its Safety Act authority. As 

discussed at much greater length in Section IV.A, NHTSA has authority under the “necessary 

expense” doctrine to enter into agreements or contracts to ensure the existence of sufficient 

communications and security systems to support deployment of V2V technologies as required by 

FMVSSs. As part of that authority, an SCMS agreement or contract could be designed with 

adequate government oversight to ensure that the SCMS is supporting V2V communications in a 

secure, privacy-appropriate way. Some of the likely primary areas covered in an SCMS 

agreement or contract might include the nature of the services provided, both on an initial and on 

an ongoing basis; requirements for system access; requirements to foster user/data privacy; 

requirements for system security; user fees; data ownership and access; liability; enforcement; 

and what to do in the event of default or termination.

However, if private industry does not establish the required communications 

infrastructure without government intervention (which is possible), NHTSA will need to exercise 

its authority to enter into a contract or agreement to establish the necessary communications and 

security pieces of a V2V system and will need someone on the other end of that contract or 

agreement. With no appropriations (i.e., no ability to pay the entity performing this role) 

 

112 See discussion above regarding the Sixth Circuit’s finding in Chrysler, 472 F.2d at 659, 666, and 671-75 (6th Cir. 

1972).
62

currently anticipated for this purpose, the likelihood of success in finding entities willing to take 

on these considerable tasks will depend on the extent to which private entities can create 

financial models113 to support development and operation of the communications and security 

infrastructure that are consistent with the Department’s V2V principles (i.e., no recurring fees for 

consumers, appropriate privacy and security protections and extensibility to V2I and V2X 

applications). Thus, having authority is not a guarantee of success in system implementation –

the V2V system model is unlikely to work unless private industry moves forward with 

developing the security and communications infrastructure required for the V2V system or 

NHTSA is able to reach agreement with the entities who will eventually manage the security and 

communications systems in a way that encourages their performance but does not create 

unintended consequences. Potential privacy issues associated with this will be discussed in 

Section VIII.

4. Discussion of need for additional legal authority prior to taking regulatory 

actions regarding vehicle to vehicle communication

The agency already has the legal authority between the Safety Act and the necessary 

expense doctrine to create the pieces needed for a V2V system. We believe that a viable V2V

system can be established and maintained under our current authority. However, some have 

suggested that a system could potentially be better protected if NHTSA had sufficient 

appropriations to develop the capacity itself to manage the security and communications 

components of the system, and did not have to rely on contracts/agreements with other parties.

NHTSA has no current plans to seek additional funding for this purpose.

C. Non-regulatory actions required to stand up V2V communications

The largest non-regulatory actions needed to create a V2V system, as discussed above,

include the possible need to enter into contracts/agreements required to ensure the existence of 

the communications and security portions of the system (both of which will fall to the security 

system manager/owners to put in place). These could range in nature from Federal procurement 

and management of the entities making up the security and communications portion of the 

system, to procurement solely of the security and communications services themselves, via for 

cost or no-cost contracts covered by the Federal Acquisition Regulations (FAR), to one or more 

binding agreements not covered by the FAR with private entities that voluntarily ‘stand up’ the 

security and communications parts of the system.

The agency would also need to conduct a number of analyses as part of a potential future 

regulatory action to establish FMVSSs for DSRC and the V2V safety applications, such as 

 

113 A possible financial model identified by some stakeholders involves charging fees to motor vehicle and ASD 

equipment manufacturers that the n can be passed on to consumers via equipment costs.
63

evaluating the potential effect of standards on small businesses, small organizations, and small 

governmental jurisdictions under the Regulatory Flexibility Act; consulting with State, local, and 

tribal governments as appropriate and evaluating the preemptive effect of standards under 

Executive Order 13132 (Federalism); assessing the costs and benefits of the standards and 

evaluating whether we have selected the most cost-effective alternative under the Unfunded 

Mandates Reform Act of 1995 (UMRA); determining and disclosing whether we are imposing 

requirements to collect information under the Paperwork Reduction Act (PRA); and evaluating 

whether we could have used technical standards developed by voluntary consensus bodies as 

required by the National Technology Transfer and Advancement Act (NTTAA), among others.

Requirements for the agency’s analysis under the Privacy Act will be discussed in Section VIII.

Optionally, we may also decide to conduct a consumer education campaign to raise 

consumer awareness of the benefits of V2V technologies and help address potential concerns 

about security and privacy. The agency is aware of public concerns regarding the issue of 

privacy generally, and a campaign could be developed and shaped to provide clear messaging on 

the many components and operation of the V2V system specifically developed to protect 

consumer privacy. Additionally, the campaign could also provide clear messaging on the basic 

operation of V2V, along with the benefits and potential plans for a rollout.

D. Authority for the spectrum in which V2V will operate, and how it 

could affect the development of a V2V system

DSRC communications are currently designed to travel in a specific band of the 

electromagnetic spectrum – specifically, around 5.9 GHz, as allocated by the Federal 

Communications Commission (FCC) in 1999. The FCC has the authority to allocate sections of 

the spectrum to various uses within the United States,

114 and is currently considering whether to 

“share” the 5850-5925 MHz bands with “Unlicensed-National Information Infrastructure” (UNII) devices.115 This could potentially have serious consequences for the viability of V2V 

communications. Existing authorizations for U-NII devices allow them to operate only on a noninterfering basis with licensed services. Issues regarding spectrum will be discussed further in 

Section V.D.2.

U-NII devices provide short-range, high-speed unlicensed wireless connections in the 5 

GHz band for, among other applications, Wi-Fi-enabled radio local area networks, cordless 

telephones, and fixed outdoor broadband transceivers used by wireless Internet service providers. 

On April 10, 2013 the FCC published in the Federal Register, a Notice of Proposed Rulemaking 

 

114 47 U.S.C. § 303. 115 FCC docket for this issue. See http://apps.fcc.gov/ecfs/proceeding/view?name=13-49 (last accessed Jan. 28, 

2014).
64

to revise Part 15 of its Rules to permit U-NII devices in the 5.580-5.925 GHz band.116 DOT 

submitted comments to the FCC NPRM to the National Telecommunications and Information 

Administration and NTIA filed those comments with the FCC June 10, 2013.117 The June 10, 

2013 comments indicated DOT’s technical concerns related to spectrum sharing with U-NII 

devices in the 5.9 GHz band, that identified the absence of (1) any proposed technical sharing 

solution with U-NII devices that would definitively maintain the channel (or medium) access 

required to guarantee interference-free operation of the critical safety applications; or (2) an 

assessment of the technical risk to Connected Vehicle safety operations of potential interference 

from U-NII devices. DOT plans to remain actively involved in the ongoing discussions and

technical analyses relating to the FCC rulemaking proceeding and will continue working with 

NTIA on this spectrum issue.

 

116 78 Fed. Reg. 21320, at 21321(Apr. 10, 2013). 117 DOT’s comments, as submitted by NTIA. See: 

http://apps.fcc.gov/ecfs/comment/view;jsessionid=hGpQRykFTJLGq48qstFl7wBR2RvJbHBFhCbt470V7ykR1fTv

Q2Wy!-528136363!-1469015862?id=6017448690 (last accessed Jan. 28, 2014).
65

V. Technical Practicability

A. Technical practicability and its importance to an agency decision

Technical practicability is a measure of how feasible a standard is given the technology 

options that are available to meet it. Significant technical uncertainties in meeting a standard 

might lead a court to find that a standard is not practicable. V2V technology is currently fairly 

mature – certainly mature enough to function in the Safety Pilot – and we anticipate that future 

research will address any lingering uncertainty with how either DSRC or the safety applications 

should function. The following discussion covers the current state of the agency’s knowledge of 

the different pieces and parts necessary for a V2V system, their technological readiness, and 

what research may be appropriate going forward. This section does not discuss the security of 

V2V communications nor the system contemplated to ensure that security, both of which are 

addressed in Section IX.

B. Overview of hardware components enabling system operation

In general, two sets of components are needed for V2V communications to operate. The 

first set of components are those required for a device to transmit an accurate and trusted basic 

safety message and the second are the components needed for a device to receive and interpret a 

BSM transmitted from another entity.

To generate and send a BSM, a device needs to know its own position (such as via a GPS 

antenna and receiver). Once its position is known, the device needs a computer processing unit 

that can take its location and combine this with other onboard sensors (e.g., speed, heading, 

acceleration) to generate the required BSM data string. Once the BSM is generated, a device is 

needed to transmit this message wirelessly to another vehicle. As the onboard processor is 

generating the BSM, a security module is processing and preparing the security information and 

certificates for transmission to provide the receiving vehicle assurance that the message is valid.

This security information needs to be transmitted wirelessly as well.

To receive and interpret a BSM, a device must be capable of receiving the BSM that is 

transmitted from a nearby device and it must match the method of BSM transmission (i.e., if the 

message is transmitted via DSRC, the receiving device must have a DSRC receiver). It also must 

have a computer processing unit that can decode the BSM properly. A GPS antenna and receiver 

are needed to verify the relative distance between the sending device and the receiving device.

Lastly, the device that is receiving the BSM must also have a security module that is capable of 

receiving and processing the security credential information as well.

Lastly, to operate the safety applications adequately to warn drivers, a driver-vehicle 

interface is needed to display critical advisories and imminent alerts. This DVI may take the 
66

form of a visual heads-up display or infotainment screen displays, LEDs and blinkers located 

strategically around the driver’s field of view, audible noises, and/or haptic feedback peripherals.

1. Components used in testing

DOT has conducted a significant amount of research on DSRC-based vehicle-to-vehicle 

communications. In 2012, building on this research, the Department initiated the Safety Pilot

Program in Ann Arbor, Michigan, in order to collect data to be used to evaluate V2V technology 

in relation to light vehicle operations. The different types of DSRC-based devices, used in the 

vehicles that were deployed in Ann Arbor, are: (1) Integrated Vehicle Devices (OEM devices) , 

which were installed (integrated by OEMs) into 64 new vehicles (8 per the 8 OEMs participating 

in the Safety Pilot); (2) Aftermarket Safety Devices (elsewhere called “self-contained” devices), 

which were installed into 270 light vehicles supplied by volunteer subjects; (3) Vehicle 

Awareness Devices, which were installed in over 2,400 volunteer private vehicles and various 

fleet vehicles such as schools buses; and (4) Integrated and Retrofit Safety Devices, which were 

also installed in heavy trucks (19) and transit buses (3) to support later evaluation of heavy truck 

and transit bus safety applications.

These DSRC-based devices had varied characteristics and served different purposes in 

being included in the Program. The main device, an integrated vehicle device, is an electronic 

device that is inserted into a vehicle during its manufacture. This type of device is connected to 

proprietary data buses and can provide highly accurate information using in-vehicle sensors to 

generate the BSM. It can both broadcast and receive BSMs, as well as process the content of 

received messages to provide warnings and/or alerts to the driver of the vehicle in which it is 

installed.

As described in Section III.D.2.a), an aftermarket safety device, as used in the Safety 

Pilot context, is an electronic device installed in a vehicle after its original manufacture, which is 

capable of both sending and receiving safety messages over a DSRC wireless communications 

link. This type of device has a driver interface, can run V2V and V2I safety applications, and can 

issue audible advisories or warnings to the driver of the vehicle. Some of the devices are 

integrated into the vehicle’s existing computer systems and are referred to as Retrofit Safety 

Devices (RSDs).118 They can receive information from the vehicle data buses and on-vehicle 

sensors. Other devices are not connected to the vehicle’s data bus. They receive the information 

needed to form the BSM from the device’s GPS, and they can also be equipped with additional 

sensors to provide more accurate information for the BSM. 

 

118 Retrofit devices that are connected to the vehicle computer system are being used in the safety pilot on transit 

vehicles and trucks. See Safety Pilot Information Sheet at www.its.dot.gov/factsheets/safety_pilot_factsheet.htm

(last accessed Jan. 28, 2014).
67

A VAD is an aftermarket electronic device installed in a vehicle without connection to 

vehicle systems, which is only capable of sending the BSM over a DSRC wireless 

communications link to alert other DSRC-equipped vehicles to its presence. Because VADs are 

not connected to the vehicle’s computer systems, all of the information for the BSM is derived 

from the device’s GPS.119 Additional sensors in these devices such as accelerometers or gyros 

can be used to provide more accurate information for the BSM. Because VADs are not equipped 

with a driver interface, they are not capable of generating warnings. VADs may be used in any 

type of vehicle, regardless of the vehicle’s age or onboard electronic systems.

2. Components required for V2V system operation

A V2V communication system requires components located in vehicles and along 

roadways to enable complete system operation. For a V2V system, this includes both the vehiclebased components and road side equipment (RSE) units to provide security updates and 

communication to the security management system. A V2I system would expand capabilities by 

embedding additional RSEs, potentially, in traffic signals, signs, and other infrastructure-related 

components. The following sections provide details on vehicle and non-vehicle based 

components.

3. Vehicle-based hardware

At a minimum, V2V devices would require two DSRC radios120 and a GPS receiver with

a processor to derive information such as vehicle speed and predicted path from the device’s 

GPS data. To improve the quality of the data that vehicle-based components could use to issue 

warnings, an inertial measurement unit to detect acceleration forces would be needed. In 

addition, a driver-vehicle interface would be essential for issuing warnings to the driver. Such 

warnings could be audial or visual (with the corresponding required hardware), or, for devices 

fully integrated into the vehicle at the time of manufacture (i.e., vehicles with Integrated Safety 

Systems), the warnings could potentially be haptic warnings (e.g., tightening of the seat belt,

vibrating the driver’s seat).

NHTSA also foresees the potential for V2V safety systems to be integrated into an 

existing electronic control unit(s) during large-scale production of vehicles equipped with these

systems. Figure V-1 illustrates the vehicle-based components needed for an integrated V2V 

system that uses integrated vehicle devices. (A V2V system with ASDs would only differ in its

lack of connection to the vehicle’s internal communications network.)

 

120 See Section V.D.2 below for more information on why NHTSA believes two DSRC radios would be necessary.
68

Figure V-1 In-Vehicle Components of a V2V System

a) Production feasibility of vehicle-based components

The Safety Pilot Model Deployment hardware consists of pre-competitive, prototype 

components—some that would be required for a production implementation and others that 

would not. For example, the extensive data acquisition systems, which are used to log driver 

behavior and vehicle information, collect information that is used only for the needed post-test 

analysis. Most likely, they would not be needed by the agency if the V2V system was deployed 

in mass production.

However, many components being used in the Model Deployment could be leveraged to 

develop products further for full scale production. In some cases, prototype components used in 

the Safety Pilot have the appearance and packaging of what could be a regular production device.

NHTSA’s current understanding, based on discussions with industry OEMs and suppliers, is that 

securing and preparing manufacturing facilities is the major factor to transitioning from building 

prototype components to ramping up to produce mass market components, and that the device in 

its current form is nearly production-feasible today.

A minor condition for production feasibility is the need for automotive-grade DSRC 

microchips for devices that would be permanently mounted in a vehicle (e.g., integrated OEM or 

aftermarket retrofit devices). Automotive grade components are usually certified to more 

stringent environmental conditions and quality (defects per parts per million) requirements than 

consumer electronics. Each vehicle manufacturer has its own set of specifications for the 

components it purchases for the vehicles it produces. Automotive grade components must be 
69

able to operate in more extreme conditions such as temperature, vibration, and electro-magnetic 

interference that go beyond the conditions for typical consumer grade components. The Safety 

Pilot employs prototype DSRC microchips that are based on consumer grade components that 

are custom-modified to be DSRC-capable. Actual DSRC chips will need to be developed for 

production and qualified as automotive grade components. As the prototype microchips are 

based on existing consumer grade wireless microchips with minimal modification, the agency 

believes feasibility for these components moving to production should not be an issue to move 

forward.

b) Projected availability of vehicle-based components

Discussions with equipment suppliers have indicated that there is the potential to have an 

adequate supply of readily available, mass-produced, internal components for a V2V device 

approximately 2.5 to 3 years after NHTSA moves forward with some type of regulatory 

action.121

4. Non-vehicle-based hardware

In addition to the vehicle-based V2V components, a V2V system also requires equipment 

to be located along roadsides and, if expanded V2I capabilities are sought, to be embedded in 

other infrastructure support equipment such as traffic signals or stop signs.

Roadside equipment is the term used to refer to the physical wireless communications 

infrastructure that supports communication between the vehicle and the SCMS, and between the 

vehicle and V2I applications. There are two types of RSEs with which a vehicle can 

communicate: RSEs that serve as a wireless communications link between the vehicle and the 

SCMS so that the vehicle can receive new security certificates, report misbehavior, and receive 

CRL updates, and RSEs that broadcast messages needed to support V2I applications. The 

equipment necessary to support both functions can be located within one RSE device. RSEs 

could employ DSRC, or could potentially use some other communications medium such as 

existing 3G/4G cellular networks or Wi-Fi.

a) External equipment used in Safety Pilot

There are 26 DSRC-equipped roadside units being used to support the Safety Pilot Model 

Deployment program. The DSRC RSEs used in the Model Deployment are all technically 

capable of both storing and forming messages to support V2I applications and to support 

communications between OBE and the SCMS.122 Specifically, the Model Deployment program 

 

121 Preliminary estimates are based on confidential information provided by two suppliers. 122 All RSEs used in the Safety Pilot Model Deployment conformed to “5.9GHz DSRC Roadside Equipment” 

Device Specification Version 3.0. See www.its.dot.gov/safety_pilot/pdf/T-10001-T2-

05_RSE_Device_Design_Specification_v30.pdf (last accessed Feb. 7, 2014).
70

is evaluating DSRC RSE devices that allow vehicles to receive updated security certificates123

and messages to support V2I applications (SPaT, curve warnings, and curve speed warnings). 

The Model Deployment is also evaluating the use of existing 3G/4G cellular networks to provide 

vehicles with updated security certificates, because DOT wanted to examine the feasibility of 

supporting communications between vehicles and the SCMS though an existing communications 

infrastructure. While it is important to note that a nationwide network of RSE DSRC devices 

does not exist at this time and Congress has yet to allocate funds to build such a network, 

existing 3G/4G cellular networks could potentially be used to support communications between 

vehicles and the SCMS in the event that a nationwide network of RSE devices is not available.

b) External equipment needed for widespread deployment

In a widespread deployment scenario, NHTSA expects much more communication 

between vehicles and the SCMS than has occurred in the context of the Safety Pilot. For 

communications to support the security system, the data will be exchanged between the OBE and 

the SCMS using the well-known Internet Protocol (IP). The basic transaction will be that the 

OBE will send a request message bearing the SCMS IP address to the RSE, and the RSE will 

forward this to the backhaul,124 where it will eventually be routed to the SCMS following the 

conventional Internet routing process. It is estimated that around 19,000 roadside DSRC units 

would be needed to support communications between vehicles and the SCMS under the current 

security framework.125

C. Overview of software enabling system operation

V2V communications is based on the wireless exchange of messages between vehicles. 

The messages provide information that a device can then use to provide a warning about 

potential danger through a safety application. Fundamentally, the basic hardware of a DSRC 

device is analogous to a common radio that not only receives information but transmits data as 

well. As a result the “core” of a DSRC device will be the software that gives devices the 

“intelligence” needed to determine and transmit current vehicle conditions and perform the 

necessary evaluations to potentially issue a warning. At the most basic level, a device will 

require low-level components to both transmit and receive the basic safety message; a relatively 

simple operating system; connection to a driver-vehicle interface; and algorithms to control the 

issuance of warnings (along with continual device diagnosis).

 

123 The security system used in Safety Pilot Program did not involve distribution of a CRL but used a “test” CRL to 

prove transmittal, receipt, and action. 124 “Backhaul” is a term used to refer to all telecommunications infrastructure, such as fiber optic cables and routing 

switches, needed to support IP protocol transactions. 

125 Communications Data Delivery System Analysis for Connected Vehicles: Revision and Update to Modeling of 

Promising Network Options, at 31 (Booz Allen Hamilton, Inc., May 2013). [Hereafter, “BAH CDDS Final Report”]. 

See Docket No. NHTSA-2014-0022.
71

Overall, both vehicle manufacturers and consumer electronic device manufacturers have 

years of significant experience developing similar software for the myriad devices and products 

they produce. They are skilled at managing suppliers to develop these components or, in some 

cases, developing device software in-house as part of their core intellectual property.

V2V devices present a new challenge to the agency regarding software and potential 

regulatory action. NHTSA’s FMVSSs are generally performance-based, but the agency has not 

yet attempted to regulate software using performance tests, and software is increasingly 

pervasive in today’s vehicles. The agency will need to consider carefully how to develop 

appropriate tests to regulate the software-based aspects of V2V communications and safety 

applications. NHTSA’s research program concerning vehicle automation includes research into 

how the agency might regulate safety-critical software.

D. Interoperability

1. Interoperability and its importance

In order for the information in a V2V communication to be useful, it must be received 

timely, it must be reliable, and it must be transmitted in a standard format. Vehicles participating 

in the V2V communications network communicate with other connected vehicles using 

standardized DSRC message types broadcast on a standardized network, IEEE 1609.4, over a 

standardized wireless layer, IEEE 802.11p.126 DSRC provides local-area, low-latency127 network 

connectivity, and is generally intended to support broadcast messaging between vehicles and 

between vehicles and roadside access points. It is a variant of Wi-Fi that allows nearly 

instantaneous network connections, as well as broadcast messaging that requires no network 

connection. It uses 75 MHz of spectrum located in the 5.85 to 5.925 GHz frequency band.128

Vehicles currently use channel 172 to transmit messages that support safety of life applications. 

Interoperability, in short, is the ability for different devices using V2V systems sourced, 

manufactured, and installed by various OEMs and aftermarket retailers to communicate with 

each other in a reliable and timely manner. If devices from different sources fail to “speak the 

 

126 See Section V.D.1.c) below for more information on these standards.

127 Latency is a measure of the time delay experienced in a system, usually between the sending, and subsequent 

reception, of information. In communications, the lower limit of latency is determined by the physics of transmitting 

a message, where the medium (radio, fiber optics, copper wiring, etc.) being used for communications can affect 

transmission speed. In addition, delays can also be incurred by the addition of data handling protocols, message 

routing and switching, and a few other smaller factors. For more information, see

www.o3bnetworks.com/media/40980/white%20paper_latency%20matters.pdf (last accessed Feb. 25, 2014). DSRC 

can be considered to be low latency because it consists of point to point communication over very short distances 

(less than 300 m) with relatively few messaging protocol requirements using radio (in air, radio transmits 

information at approximately light speed). 128 This is usually referred to as the 5.9 GHz band.
72

same language,” then the system as a whole will not be “interoperable,” and will consequently 

degrade and break down.

a) Communication between vehicles

V2V communications consists of two types of messages: safety messages and certificate 

exchange messages. The safety messages are used to support the safety applications, and the 

certificate exchange messages ensure that the safety message is from a trusted source. The safety 

messages are transmitted in a standardized format so that they can be read by all other vehicles 

participating in the network. To satisfy this requirement, each DSRC-equipped vehicle would 

need to broadcast and receive safety messages in a standardized format and specified 

performance level in terms of characteristics like accuracy and range.129 Additional details on 

standards related to V2V can be found in Section V.D.1.c). The safety messages include 

information about the vehicle’s behavior such as the vehicle’s GPS position, its predicted path, 

its lateral and vertical acceleration, and its yaw rate. The messages are time-stamped so the 

receiving vehicle knows when the message was sent. This information can be used by other

vehicles for a variety of crash avoidance applications.

NHTSA’s current research is based on the assumption that the V2V system will use a 

Public Key Infrastructure (PKI) to authenticate messages, so that other vehicles will trust the 

m.130 PKI uses certificates to inform a receiving device that the message is from a trusted source, 

and it uses cryptography to send encrypted message content. For V2V communications, BSM 

messages are trusted but not encrypted, while messages that contain security information (e.g., 

certificates) are trusted and the contents encrypted.131

The security system currently being researched for V2V would use a type of 

cryptography known as “asymmetric cryptography.”132 In asymmetric cryptography, there are 

two keys that are mathematically linked in such a way that what is encrypted with one key can 

only be decrypted with the other. Although the keys are mathematically linked, it is extremely 

difficult to derive one key based on knowledge of the other. This property allows one key, the 

“public key,” to be widely distributed while the other key, the “private key,” is held only by the 

owner. Asymmetric cryptography (both encryption and decryption) is computationally harder 

 

129 Such as, for example, the parameters as defined in SAE J2735. 130 BAH CDDS Final Report, at 9. 131 Certificates decrease latency as compared to encrypting the BSM itself; encrypting the BSM, sending it, and the n 

the other vehicle receiving, decrypting, and translating it could take longer than what would support effective 

functioning of the safety applications.

132 Also known as public key encryption.
73

than symmetric cryptography and is one of the reasons many security experts believe asymmetric 

cryptography to be more secure.133

Many Internet security protocols use asymmetric cryptography as the basis for their 

infrastructure. Secure socket layers/transport layer security (SSL/TLS),

134 the protocol used in 

most secure online transactions, uses asymmetric encryption to authenticate the server to the 

client, and optionally the client to the server. Asymmetric cryptography is also used to establish a 

session key. The session key is used in symmetric algorithms to encrypt the bulk of the data.

This combines the benefit of asymmetric encryption for authentication with the faster, less 

processor-intensive symmetric key encryption for the bulk data.

135 The secure form of Hypertext 

Transfer Protocol is HTTPS, which operates as a PKI system and uses SSL. SSL\TLS also 

operates on its own as a PKI system, independently of HTTPS. For a further discussion of 

symmetric and asymmetric cryptography, please see Section IX.

b) Vehicle-to-Vehicle Message Sets

For vehicle communication to succeed among OEM-installed in-vehicle devices and 

aftermarket devices, communication messages must be standardized so that the devices speak the 

same language. SAE J2735 is intended to help address this purpose so that all V2V safety 

applications are built around a common framework. SAE J2735 defines the design specifications 

for the safety messages, including specifications for the message sets,136 data frames,137 and data 

elements.138

 

133 Symmetric encryption is a very common encryption scheme that many use routinely, possibly without knowing 

the exact name for it. In fact, before 1973, all known encryption algorithms were symmetric. If the reader has ever 

“password protected” a .zip file, where the same passphrase (key) is used to both lock and unlock the .zip file, then 

symmetric encryption was used. Similarly, a “Secret Decoder Ring,” where a ring containing 2 sets of alphanumeric 

strings (located on different halves of the ring) can be rotated relative to each other to develop an encryption 

scheme, is another example of symmetric cryptology, as the orientation of the two sides of the ring used to encrypt a 

message is also needed to decode the secret message. One challenge with symmetric cryptography is controlling key 

distribution so that the key does not fall into unintended hands. 134 Secure Sockets Layer/Transport Layer Security (SSL/TLS) is a protocol primarily used to encrypt confidential 

data sent over an insecure network, such as the Internet.

135 For an overview of SSL/TLS encryption, see http://technet.microsoft.com/en-us/library/cc781476(v=ws.10).aspx

(last accessed Jan. 28, 2014).

136 As defined in SAE J2735, a message is a well-structured set of data elements and data frames that can be sent as 

a unit between devices to convey some semantic meaning in the context of the applications. A message set is a 

collection of messages based on the ITS functional-area to which they pertain. 137 As defined in SAE J2735, from a computer science perspective, data frames are viewed as logical groupings of 

other data frames and of data elements to describe "structures" or parts of messages used in SAE J2735 and other 

standards. A data frame is a collection of two or more other data concepts in a known ordering. These data concepts 

may be simple (data elements) or complex (data frames). 

138 As defined in SAE J2735, a data element is a syntactically formal representation of some single unit of 

information of interest (e.g., a fact, proposition, observation) with a singular instance value at any point in time, 
74

(1) The Basic Safety Message

The currently-published version of SAE J2735, published in November 2009, is the 

second version of the standard. It specifies 15 message sets, with Basic Safety Message the most 

important one.139

As explained above, the BSM is used to exchange safety data regarding vehicle state. The 

message is broadcast routinely to surrounding vehicles with a variety of data content. The BSM 

is split into two parts to guarantee that the core information for vehicle safety (Part I) has priority 

and is transmitted more often. It also minimizes the amount of data communicated (most of the 

time) between devices, helping to reduce channel congestion.

BSM Part I contains the core data elements, such as vehicle position, speed, heading, 

brake system status, and vehicle size. Details of the BSM Part I content are found in Table V-1.

 

about some entity of interest (e.g., a person, place, process, property, object, concept, association, state, event). A 

data element is considered indivisible.

139For more information on the other message sets defined in SAE J2735, see www.sae.org/standardsdev/dsrc/ (last 

accessed Jan. 28, 2014).
75

Table V-1 Contents of BSM Part I140

Part I

Data Frame (DF) Data Element (DE)

Position (DF) 

Latitude* 

Elevation* 

Longitude* 

Positional accuracy* 

Motion (DF)

Transmission state*

Speed

Steering wheel angle

Heading*

Longitudinal acceleration* 

Vertical acceleration

Lateral acceleration 

Yaw rate*

Brake applied status 

Traction control state 

Stability control status 

Auxiliary brake status 

Brake status not available 

Antilock brake status 

Brake boost applied 

Vehicle size (DF)

Vehicle width 

Vehicle length

*Required in Safety Pilot Model Deployment

BSM Part II contains a set of data elements that can vary by vehicle model. Part II data 

are only broadcast when an event happens that changes the Part II data content. Part II is then 

appended to Part I data and broadcast; otherwise, only Part I data is transmitted in the BSM. The 

content of Part II data depends on the triggering events – not all Part II data will be transmitted 

simply because some Part II data is transmitted. For example, when a vehicle activates ABS, a 

 

140 Based on SAE 2735-2009. For more information, see “Vehicle Information Exchange Needs for Mobility 

Applications: Version 2.0, Revised Report (Aug. 1, 2012, FHWA-JPO-12-021) at 

http://ntl.bts.gov/lib/46000/46000/46089/Final_PKG_FHWA-JPO-12-021_508_PDF.pdf (last accessed Jan. 28, 

2014).
76

data element named “ABS activated” is set and the vehicle’s BSM transmissions include a Part II 

message indicating that its ABS is active.141 This event type data is being used in the Safety Pilot 

Model Deployment to support the EEBL safety application. Consequently, Part II data are 

transmitted less frequently. Details of the BSM Part II content are found in Table V-2.

Table V-2 Contents of BSM Part II142

Part 2 (all elements optional, sent according to criteria to be established)

Data Frame (DF) Data Element (DE)

Vehicle safety extension (DF)

Event flags (DE) – A data element consisting of single 

bit event flags:

Hazard lights

Intersection stop line violation

ABS activated

Traction control loss

Stability control activated

Hazardous materials

Emergency response

Hard braking

Lights changed

Wipers changed

Flat tire

Disabled vehicle

Air bag deployment

Path history (DF)

Full position vector (DF)

Date and time stamp (DE)

Longitude (DE)

Latitude (DE)

Elevation (DE)

Heading (DE)

Transmission and speed (DF) – same as in Part 1

Positional accuracy (DE)

Time confidence (DE)

Position confidence set (DF)

Position confidence (DE)

Elevation confidence (DE)

Speed and heading and throttle confidence (DF)

 

141For the same event, the traction control loss, stability control activated, and the hard braking flags may be set as 

well depending on the event type and causation.

142 See supra note 140.
77

Speed confidence (DE)

Heading confidence (DE)

Throttle confidence (DE)

GPS status (DE)

Count (DE) – number of “crumbs” in the history

Crumb data – set of one of 10 possible path history point set types, consisting of various 

combinations of:

Latitudinal offset from current position (DE)

Longitudinal offset from current position (DE)

Elevation offset from current position (DE)

Time offset from the current time (DE)

Accuracy (DF) – See J2735 standard for more information

Heading (DE) – NOT an offset, but absolute heading

Transmission and speed (DF) – same as in Part 1, NOT an offset

Path Prediction (DF) Radius of curve (DE)

Confidence (DE)

RTCM Package (DF) – RTCM (Radio Technical Commission for Maritime Services) is a 

standardized format for GPS messages, including differential correction messages. 

Full position vector (DF) – see full contents above under Path history

RTCM header (DF)

GPS status (DE)

Antenna offset (DE)

GPS data – see SAE J2735 and RTCM standards for 

more information

Vehicle status (DF)

Exterior lights (DE)

Light bar in use (DE)

Wipers (DF)

Wiper status front (DE)

Wiper rate (front) (DE)

Wiper status rear (DE)

Wiper rate (rear) (DE)

Brake system status (DF) – same as in Part 1

Braking pressure (DE)

Roadway friction (DE)

Sun sensor (DE)

Rain sensor (DE)

Ambient air temperature (DE)

Ambient pressure (DE)

Steering, sequence of:

Steering wheel angle (DE)

Steering wheel angle confidence (DE)

Steering wheel angle rate of change (DE)

Driving wheel angle (DE)
78

Acceleration set (DF) – same as in Part 1

Vertical acceleration threshold (DE)

Yaw rate confidence (DE)

Acceleration confidence (DE)

Confidence set (DF)

Acceleration confidence (DE)

Speed confidence (speed, heading, and throttle confidences (DF)

Time confidence (DE)

Position confidence set (DF)

Steering wheel angle confidence (DE)

Throttle confidence (DE)

Object data, sequence of:

Obstacle distance (DE)

Obstacle direction (DE)

Time obstacle detected (DE)

Full position vector (DF) – see contents under path history

Throttle position (DE)

Speed and heading and throttle confidence (DF) – same as above under “Full position 

vector”

Speed confidence (DE) – same as above under “Speed 

and heading and throttle confidence”

Vehicle data (referred to as a “complex type” in J2735, rather than an element or frame)

Vehicle height (DE)

Bumper heights (DF)

Bumper height front (DE)

Bumper height rear (DE)

Vehicle mass (DE)

Trailer weight (DE)

Vehicle type (DE)

Vehicle identity (DF)

Descriptive name (DE) – typically only used for 

debugging

VIN string (DE)143

Owner code (DE)144

Temporary ID (DE)

Vehicle type (DE)

 

143 SAE J2735 is a data dictionary that defines potential data elements for a number of messages (e.g., V2V, V2I, 

I2V, probe messages). Data elements are currently defined within the standard for a broad range of future safety and

non-safety application messages. The vehicle identification data elements are defined for communication between 

emergency and fleet vehicles for applications such as traffic signal preemption, in which the road side equipment 

(traffic signal controller) requires confirmation of the identity of the vehicle. 144 Id.
79

Vehicle class (drawn from ITIS code standard)

J1939 data (DF)

Tire conditions (DF) – see J2735 standard for list of data elements

Vehicle weight by axle (DF) – see J2735 standard for list of data elements

Trailer weight (DE)

Cargo weight (DE)

Steering axle temperature (DE)

Drive axle location (DE)

Drive axle lift air pressure (DE)

Drive axle temperature (DE)

Dive axle lube pressure (DE)

Steering axle lube pressure (DE)

Weather report, defined as a sequence of the following:

Is raining (DE) – defined in NTCIP standard

Rain rate (DE) – defined in NTCIP standard

Precipitation situation (DE) – defined in NTCIP 

standard

Solar radiation (DE) – defined in NTCIP standard

Mobile friction (DE) – defined in NTCIP standard

GPS status (DE)

The SAE J2735-2009 standard contains only technical design specifications for the BSM, 

so in order to specify the usage of the BSM as defined in J2735, such as the transmission rate, 

power level, data integrity, etc., another set of standards for the minimum communication 

performance requirements for the BSM must be developed. The SAE DSRC Technical 

Committee is currently in the process of developing minimum performance requirements for 

BSM communication, named SAE J2945-1, based on the knowledge gained through the CAMP 

VSC-A project, the V2V-Interoperability project and the Safety Pilot Model Deployment.

Standards Need V-1 SAE Standards Maturity

Standards Need: SAE J2945 & SAE J2735

Description: Currently these standards are in development. Timeframe for completion 

and impact on future regulatory is to be determined by outside 

organizations

(2) Other options besides the BSM

The BSM is developed specifically for vehicle-to-vehicle communication, to allow 

devices from different OEMs and suppliers to interact in the system. This dedicated message was 

cooperatively developed as a standard involving both U.S. and EU representatives. Currently 

there is no planned alternative to using the collaboratively-developed BSM to transmit and 
80

receive vehicle information for use in safety applications. The BSM has been developed and 

refined over the course of the last decade specifically to support common V2V communication.

(3) Current maturity level of V2V message sets

The BSM is developed for vehicle-to-vehicle communication to allow devices from 

different OEMs, suppliers, and aftermarket device manufacturers to communicate with each 

other for V2V and V2I applications. The preliminary design specifications for the BSM are 

contained in the current version of SAE J2735 and preliminary minimum performance 

requirements will be contained in SAE J2945 when finalized.

Over the course of the Safety Pilot, it was identified that the current published J2735-

2009 will not support interoperability as a stand-alone document, due to ambiguities in the 

standard that were causing OEMs and suppliers to interpret the standard and define the BSM 

inconsistently. During the V2V-I project, future revision items were identified for various DSRC 

standards for further improvement for interoperability.

Nevertheless, the vehicles in the Safety Pilot Model Deployment program are 

transmitting BSMs to each other and using those BSMs to activate safety applications. Results 

from the Safety Pilot and the CAMP Interoperability project will be used to further develop 

performance requirements for the BSM.

c) Technical Standards related to V2V

(1) Development and use of technical standards related to V2V

To support wireless communication between two or more vehicles and/or between 

vehicles and fixed or nomadic devices, a set of ITS V2X Cooperative System Standards are 

needed. These standards ensure that vehicles are interoperable and can interpret messages 

received from these other sources. The current set of cooperative system standards is found in 

Table V-3.

Table V-3 Cooperative System Standards for V2V Communications

Cooperative System Standards

IEEE 802.11p-2010

IEEE P1609.0/D5.8

IEEE 1609.2-2013

IEEE 1609.3-2010

IEEE 1609.4-2010

IEEE 1609.12-2012

SAE J2735, Version 2

SAE J2945.1, Version 1
81

These cooperative system standards were developed specifically to support V2V and V2I

wireless interfaces. They establish a wireless link for V2V and V2I communications (IEEE 

802.11p), establish protocols for information exchange across the wireless link (IEEE 1609.x), 

and define message content for communicating specific information to and from equipment and 

devices via DSRC (SAE J2735 and SAE 2945.x) or other communications media.

OST-R’s Intelligent Transportation Systems Joint Program Office’s Standards Program 

funds and manages ITS cooperative system standards efforts in support of V2V and V2I

technologies. The content of these standards is developed collaboratively with contributions from 

diverse stakeholders. The VSC-A and CAMP projects have made significant contributions to 

many of the standards described above.145

The cooperative system standards are, to be clear, consensus standards voluntarily 

followed by industry, as compared with regulations issued by a government agency like NHTSA.

NHTSA has no authority to enforce standards that it does not promulgate. However, if NHTSA 

eventually decided, for example, to mandate DSRC (in order to enable certain safety 

applications), part of that mandate would likely include requirements that DSRC devices be 

interoperable in order to ensure that they function properly. Part of ensuring interoperability is 

making sure that DSRC works, exchanges information the same way every time, and uses 

standardized messages. Each of the cooperative system standards discussed in this section 

facilitates some part of DSRC operation, so NHTSA may look to these standards and incorporate 

elements of them if the agency decides to pursue a DSRC mandate.

(2) SAE J2735 - DSRC Message Set Dictionary

The SAE J2735 standard specifies message sets, data frames, and data elements that 

make up messages/dialogs specifically for use by applications intended to use the 5.9 GHz 

DSRC for WAVE communications systems. The messages for V2V safety applications are 

defined in SAE J2735 as the BSM parts 1 and 2 (detailed information for BSM part 1 and 2 can 

be found in Section V.D.1.b) other parts of SAE J2735 define the message sets for other ITS 

applications, such as weather and mobility.

SAE’s DSRC Technical Committee issued the current published version of J2735 in 

November 2009, as version 2 of the standard (referred to as J2735-2009 or version 2 of J2735).

At present, the SAE J2735-2009 standard has been implemented for testing and experimental 

 

145 Specifically, VSC-A and CAMP have contributed to the development of SAE J2735 (DSRC Message Set 

Dictionary); SAE J2945.1 (DSRC BSM Minimum Performance Requirements); IEEE 1609.0 (Architecture); IEEE 

1609.2 (Security Services); IEEE 1609.3 (Networking Services); IEEE 1609.4 (Multi-Channel Operation); IEEE 

1609.12 (Identifier Allocations); and IEEE 802.11p (Wireless Access in Vehicular Environments (WAVE)).
82

purposes only, with no wide-scale deployment. As indicated in the discussion on maturity of the 

BSM message sets, revisions will be necessary to the J2735-2009 standard to support widespread 

deployment of a V2V system. Current expectations are that a revised standard will be published 

in late 2014.

(3) SAE J2945 - DSRC Minimum Performance Requirements

The SAE J2945.1 standard specifies the minimum communication performance 

requirements of the DSRC Message sets and the necessary BSM data elements to support V2V 

safety applications. The J2945.1 standard is part of a future family of J2945.x standards.146 The

current draft standard consists of multiple sections with each section describing the specific 

requirements for using the BSM for V2V safety applications. The content of the current draft 

J2945.1 is listed in Table V-4. To date, an early rough draft version of J2945.1 exists and it only 

includes the minimum communication performance requirements for the BSM message. It is 

anticipated the published version of J2945 will be available in late 2014.

Table V-4 Contents of Draft J2495.1 Standard147

Section Section Title

1 Scope

2 References

3 Common Section

3.1 PSID Assignment

3.2 SSP (Service Specific Priority)

3.3 Message Priority Mapping

4 DSRC BSM Minimum Performance Requirements

4.1 Power option

4.2 DSRC Communication Channel Operation for BSM (or V-V Safety)

4.3 BSM Transmission Interval Requirements

4.4 Transmission Power Requirements

4.5 Security and Privacy Requirements

4.6 GPS configuration Requirements

4.7 Data Frame/Elements Requirements

5 Future Consideration

6 Application-level Requirements?

7 Other stuff*

*Note: [sic], per the current draft form of the standard

 

146 Each J2945.x standard will provide the critical interface information needed to support one or more applications.

Associated design specifications for data frames and data elements for the respective J2945.x standards are defined 

in the SAE J2735-2009 (DSRC Message Set Dictionary standard) and will also be included in future published 

versions of J2735.

147 This outline is from the current draft J2945.1, and will likely change as the standard is further developed.
83

(4) IEEE 1609 - Standard for Wireless Access in Vehicular Environments 

(WAVE)

The IEEE 1609 Family of Standards for Wireless Access in Vehicular Environments 

(WAVE) define an architecture and a complementary, standardized set of services and interfaces 

that collectively enable secure V2V and V2I wireless communications. Together these standards 

are designed to provide the foundation for a broad range of applications in the transportation 

environment, including vehicle safety, automated tolling, enhanced navigation, traffic 

management, and others.

(5) IEEE 1609.0 - Guide for Wireless Access in Vehicular Environments 

(WAVE) Architecture

IEEE 1609.0 is not a standard, but an architecture guide. It provides the descriptions of 

each of the full-use IEEE 1609 standards and their relationships to other relevant standards (such 

as IEEE 802.11), and includes guidance on how they should work together. The protocol 

architecture, interfaces, spectrum allocations, and device roles are all described. The guide is 

intended for organizations that will implement DSRC, such as State departments of 

transportation, automobile and original equipment manufacturers, aftermarket equipment 

makers, application developers, and standards developers. The guide describes the history of the 

development of the IEEE 1609 standards that includes the ITS architecture, the FCC allocation 

of the spectrum, and the original standards activity in the development of ASTM 2213-03. Also 

described are the IEEE 1609 trial use standards and IEEE 802.11. There is also a summary of the 

deployment history of DSRC devices in an annex to the guide. Overall WAVE system operations 

are described and an example system configuration is provided based on the published full use 

standards. The protocol architecture is described, including a description of the data plane,148 the 

management plane,149 and how WAVE messages and IPv6 messages are treated. Internal and 

external interfaces are described. The channel configurations, channel types and allowed 

operations are detailed according to the current FCC rules as well as a description of how the 

control channel and the service channels can be configured. The guide also explains channel 

coordination, channel switching, and time synchronization.

(6) IEEE 1609.2 - Security Services for Applications and Management Messages

The safety-related content of WAVE applications, and particularly vehicle safety 

applications, makes it necessary to protect messages from attacks such as eavesdropping, 

spoofing, alteration, and replay. Recipients of safety messages have to be assured that the 

messages they receive are authentic and are sent by a source authorized to transmit those 

 

148 The data plane, also known as the user plane, forwarding plane, carrier plane, and/or bearer plane, is the part of a 

network architecture that handles user traffic.

149 Part of a network architecture which provides an administrative interface to the system.
84

messages. Additionally, the fact that the WAVE technology may be implemented in 

communication devices in personal vehicles as well as in other portable devices whose owners 

may have some expectation of privacy means that the security services may need to be designed 

to avoid, for example, revealing personal, identifying, or linkable information to unauthorized 

parties in systems where PII may be involved. This standard describes security services for 

WAVE management messages and application messages designed to meet these goals. This 

standard was intended to be used primarily for DSRC.

(7) IEEE 1609.3 - Networking Services

IEEE 1609.3 specifies how various message types (e.g., WAVE Short Messages, WAVE 

Service Advertisements, and WAVE Routing Advertisements) are assembled, packaged, and 

handled between an application and IEEE 1609.4 for transmission or upon reception. It describes 

how to build, route, process, and interpret WAVE low latency messages, as well as messages 

based on other well-known protocols such as the User Datagram Protocol and Internet Protocol 

Version 6 (IPv6). The standard includes information on what messages go on the control 

channel, what messages go out on the service channels, advertising specific services, 

authenticating the messages, accessing applications hosted on an external network (e.g., the 

Internet) and methods for how this can be accomplished.

(8) IEEE 1609.4 - Multi-Channel Operations

This standard describes multi-channel radio operations for WAVE. It is used in 

conjunction with other IEEE 1609 standards and IEEE 802.11-2012 to implement DSRC 

communications in the 5.9 GHz frequency band. WAVE operates using IEEE 802.11 outside the 

context of a basic service set. In order to implement functions such as user priority access to the 

media, routing data packets on the correct channel with the desired transmission parameters, and 

the ability to coordinate switching between the control channel and service channels, additional 

functions are required between the IEEE 802.11 medium access control and the Logical Link 

Control. This standard specifies how these functions are implemented.

(9) IEEE 1609.12 - Identifier Allocations

WAVE is specified in the IEEE 1609 family of standards, within which a number of 

identifiers are used. IEEE 1609.12 describes the format and use of the provider service identifier, 

and indicates identifier values that have been allocated for use by WAVE systems.

(10) IEEE 802.11p-2012 - Medium Access Control and Physical Layer 

Specifications for WAVE

IEEE 802.11 is a set of standards that specify the physical layer for implementing 

wireless local area network using Wi-Fi bands. The base version of the standard was released in 

1997 and has had subsequent amendments. IEEE 802.11 is approximately 2,800 pages long, but

only certain parts of the standard are required for implementing DSRC operating at 5.9 GHz for 
85

V2V communications. IEEE 802.11p is an approved amendment to 802.11 standards to add 

WAVE that is required to support ITS applications. In March 2012, IEEE published the latest 

version of this standard, 802.11p-2012, which includes all the amendments to this standard 

published prior to 2012.

The purpose of this standard is to describe the operation of what are commonly known as 

Wi-Fi devices, including devices such as the wireless routers and the transceivers in computers. 

To accommodate the rapid exchange of trajectory information between vehicles traveling at high 

speed, IEEE 802.11p was amended to enable operation without setting up a basic service set. It 

allows security services, such as authentication, to be provided by other standards. It describes 

adjacent channel and alternate adjacent channel interference criteria and transmission masks 

corresponding to requirements of the FCC rules for DSRC. The entire standard applies to V2V 

and V2I communications, because it defines the structure for how devices should communicate 

using the 5.9 GHz frequency band but there are no performance criteria or test procedures 

described in this amendment.

(11) Maturity of the standards

Table V-5 describes the standards representing the core cooperative system standards, in 

particular those that support V2V and V2I. While versions of these standards have already been 

developed and published, some are currently undergoing revision to support evolving needs such 

as the current Safety Pilot Model Deployment activity.
86

Table V-5 ITS V2X Cooperative System Standards Latest Publication and Current Status

Standard V2V Relevance Latest Publication 

Date Current Status

IEEE 802.11p-2010 DSRC-specific Wi-Fi device 

operations

July 2010 Finalized and published.

IEEE P1609.0/D5.8 Guide to other 1609 

standards

Not yet published. In sponsor ballot150

IEEE 1609.2-2013 Security April, 2013 Finalized and published.

IEEE 1609.3-2010 Data exchange/message 

structure

December, 2010 Finalized and published.

IEEE 1609.4-2010 Channel switching modes February, 2011 Finalized and published.

IEEE 1609.12-2012 Message identification September, 2012 Finalized and published.

SAE J2735, Version 2 Basic safety message 

elements

November 19, 2009 Revision underway and 

expected to be published in 

late 2014.

SAE J2945.1, Version 1 Basic safety message 

requirements

No published version yet. 

Expected to be published in 

late 2014.

d) Relative Positioning

Relative positioning is a critical system function/element used to enable V2V safety 

applications. The essential function of the safety applications, their ability to warn the driver of 

an impending collision, depends on the ability of the automobiles within DSRC range to report 

their GPS positions to each other with confidence in their accuracy. GPS positioning matters 

because two interacting devices need to understand where they are in relation to each other.

Relative positioning is calculated by the difference in the reported GPS position between 

two vehicles in close proximity. The quality of a relative positioning solution between two cars 

depends on how accurate the two separate GPS positioning were.151

 

150 For a description of the IEEE ballot process, see http://standards.ieee.org/develop/balloting.html (last accessed 

Jan. 9, 2014).

151 Several different modes of absolute positioning have been investigated in the positioning research performed by 

CAMP, including standalone GPS, Wide Area Augmentation System (WAAS), and Real Time Kinematic (RTK).

WAAS is an augmented GPS that uses ground reference stations to measure deviations from ground truth in the 

GPS signal and provide corrections to the geostationary WAAS satellites over the continental United States.

Although WAAS specifications call for a position accuracy of 7.6 m or better 95 percent of the time, actual accuracy 

performance has typically been better than 1.0 m lateral accuracy and 1.5 m vertical accuracy. RTK functions on the 

principle of examining the difference in the phase of the carrier wave of the GPS signal between two reference 

stations (fixed or mobile). This difference is used to improve the raw GPS calculated distance between the stations.

While RTK has the potential of high accuracy with errors measured down to a few centimeters, it comes in as more 
87

Absolute positioning by itself might seem more useful to V2V communications, insofar 

as one might think that V2V-based safety applications would have the best chance of warning a 

driver correctly given the most precise information possible about the driver’s location and the 

location of other vehicles. However, relative positioning has an inherent benefit as applied to 

V2V communications, as it relieves the burden of correcting for absolute positioning that would 

require additional communication with a RSE for each GPS location transmission, which would 

in turn require a comprehensive infrastructure network.

Error/biases in GPS raw measurements exist and are caused by natural effects and are 

almost identical over a geographic area. These natural biases are cancelled out in a relative 

positioning scheme performed over DSRC ranges. Using the relative positioning approach 

allows vehicles to calculate their position in relation to each other with a high degree of 

confidence, assuming that they have the same bias. The ability of a vehicle to determine its 

position in relation to other vehicles, rather than to determine its absolute position on the Earth, 

together with the other information transmitted in the BSM, is what is necessary to support the 

safety applications.

2. Current maturity level of V2V wireless communication channels

a) Securing a dedicated spectrum

It is widely accepted that V2V communications have a specific home in the wireless 

spectrum, but whether that home is sufficiently protected against intrusion that might impair the 

effectiveness of safety applications enabled by V2V is less clear at present. In 1999 the FCC 

allocated 75 MHz in support of the Intelligent Transportation Systems152 on a primary basis.

While this is referred to as a dedicated spectrum, it should be noted there are other allocations in 

this band, including the Fixed Service Satellite (co-primary) and Amateur Radio (secondary).

Additionally, the lower 25 MHz overlaps the Industrial, Scientific, and Medical (ISM) band.

Government Radiolocation is authorized on a primary basis as well. In February of 2004, the 

FCC released another Report and Order setting forth licensing and service rules for DSRC

services. In 2006, the FCC released an Amendment of the Commission’s Rules153 that, among 

 

costly in terms of computational and bandwidth requirement. See: VSC 2 Consortium, “Vehicle Safety 

Communications – Applications (VSC-A) Final Report: Appendix Volume 2 Communications and Positioning,” 

Report No. DOT HS 811 492C, September 2011, at

www.nhtsa.gov/Research/Crash+Avoidance/Office+of+Crash+Avoidance+Research+Technical+Publications (last 

accessed Jan. 28, 2014). [Hereafter, “VSC-A Final Report: Appendix Volume 2”]. 152 Amendment of Parts 2 and 90 of the Commission's Rules to Allocate the 5.850-5.925 GHz Band to the Mobile 

Service for Dedicated Short Range Communications of Intelligent Transportation Services (ET Docket No. 98-95) at

http://transition.fcc.gov/oet/dockets/et98-95/ (last accessed Jan. 9, 2014). 153 Federal Communications Commission, Amendment of the Commission’s Rules Regarding Dedicated ShortRange Communication Services in the 5.850-5.925 GHz band (71 Fed. Reg. 52747, Sept. 7, 2006) at 

www.gpo.gov/fdsys/pkg/FR-2006-09-07/pdf/FR-2006-09-07.pdf (last accessed Feb. 18, 2014).
88

other things, designated channel 172 exclusively for vehicle-to-vehicle safety communications 

for accident avoidance and mitigation, and safety of life and property applications. The 

amendment also designated Channel 184 exclusively for high-power, longer-distance 

communications for public safety applications involving safety of life and property, including 

road intersection collision mitigation. These FCC decisions established DSRC as the incumbent 

in the band on a co-primary basis with the Fixed Service Satellite, and the FCC’s continued 

recognition of this highlights the allocation of this spectrum for ITS.

In 2003, DOT announced the VII Proof of Concept initiative. At this point efforts shifted 

slightly from R&D into Test and Evaluation (T&E). This has continued for a number of years, 

culminating in the Safety Pilot. Data from the V2V Safety Application Research and the Safety 

Pilot will support a decision concerning the DSRC technology and if the technology can be used 

to address motor vehicles crashes.

The importance of DSRC has not been lost over the many years it has taken to develop 

and test it. In the latest 5 GHz NPRM, the FCC again notes the need to protect DSRC when they

asked “what types of sharing technology or techniques could be used to protect non-radar 

systems, such as the DSRCS which includes both road side units (RSU-fixed) and on board units 

(OBU-mobile) operating under a primary allocation.”154

b) Existing signal interference issues

Signal interference can pose challenges to V2V communication if other devices are 

operating at the same frequency as DSRC devices and preclude the transmission or reception of 

messages that could impact the effectiveness of safety applications. Existing signal interference 

deals with what devices are already using the signal and how the addition of devices using the 

same frequency (signal) would disrupt the signals of any existing devices operating at the same 

frequency. Early in the development of DSRC, the Institute for Telecommunication Sciences, the 

research arm of the National Telecommunication and Information Administration, was 

contracted to perform analysis work on signal interference by the Federal Highway 

Administration. Two reports are notable. The first report tested European and Japanese DSRC 

devices against DOD radar systems in a laboratory setting (the United States had nothing to test 

at that point in time).155 The second examined the occupancy of the DSRC band as well as 

adjacent bands, meaning what other users and/or existing services occupy the band or nearby 

 

154 Revision of Part 15 of the Commission’s Rules to Permit Unlicensed National Information Infrastructure (U-NII) 

devices in the 5 GHz Band (ET Docket 13-49) at http://apps.fcc.gov/ecfs/comment/view?id=6017164516 (last 

accessed Jan. 9, 2014).

155 Electromagnetic Compatibility Testing of a Dedicated Short-Range Communication (DSRC) System that 

Conforms to the Japanese Standard (Nov. 1998, NTIA Technical Report TR-99-359) at 

www.its.bldrdoc.gov/publications/details.aspx?pub=2390 (last accessed Jan. 28, 2014).
89

adjacent bands that could leak into the 5.9 GHz band.156 The testing with European and Japanese 

devices showed that “when combined with the additional isolation achieved by antenna 

alignment (estimated to be 40 dB), the engineers found that all of the existing 5-GHz radars 

(other users/services in the 5 GHz band)157 should be compatible with the DSRC system that was 

tested [in a worst case scenario] for extremely small separation distances (several meters or 

less).” Based on these findings, the agency believes interference should be minimal and not 

present a major impact on the effectiveness of the system.

The second report noted that interference from the Fixed Service Satellite (FSS)158 to 

DSRC is possible. Typically, the FSS uplinks are in remote and rural locations. These earthbased facilities use a high-powered uplink to transmit data to geostationary satellites, 

predominantly over the eastern Atlantic or mid to eastern Pacific Oceans. Their primary function 

is trans-ocean communications and there are relatively few around the country. An in-band 

sharing agreement was developed and submitted to the FCC several years ago. In essence, it calls 

for new sites to be coordinated such that incumbents have priority. This is a standard approach 

for co-primary allocations. The FCC has not yet acted on the agreement.

c) Current status of the spectrum

On June 28, 2010, President Obama directed the Secretary of Commerce to work with the 

FCC to identify and make available 500 megahertz of spectrum over the next 10 years for 

wireless broadband use. On February 22, 2012, the President signed the Middle Class Tax Relief 

and Job Creation Act of 2012 into law. The Act requires the Assistant Secretary of Commerce 

(through NTIA), in consultation with the Department of Defense (DoD) and other impacted 

agencies, to evaluate spectrum-sharing technologies and the risk to Federal users if UnlicensedNational Information Infrastructure (U-NII) devices were allowed to operate in these bands.

The most common types of U-NII devices include those that use Wi-Fi communication. 

These devices, in general, operate without a license, but are not supposed to interfere with 

licensed devices, and have no interference protection.159 The NTIA was required to issue a report 

eight months after enactment (October 22, 2012) on the portion of the study on the 5.350-5.470 

 

156 Measured occupancy of 5850-5925 MHz and adjacent 5-GHz spectrum in the United States (Dec. 1999, NTIA 

Technical Report TR-00-373) at www.its.bldrdoc.gov/publications/2404.aspx (last accessed Jan. 28, 2014). 157 Id. 158 Fixed Service Satellite (FSS) is the official classification for geostationary communications satellites that provide 

broadcast feeds to television stations, radio stations, and broadcast networks. FSSs also transmit information for 

telephony, telecommunications, and data communications. For more information, see

www.hq.nasa.gov/webaccess/CommSpaceTrans/SpaceCommTransSec3/CommSpacTransSec3.html#3_1_3 (last 

accessed Feb. 25, 2014). 159 The risk with these devices, however, is that they may be easily modified in ways that could result in them 

interfering with DSRC operation. Because they are unlicensed, moreover, it would be difficult to enforce against 

modified devices causing such interference. This continues to be an area of concern to NHTSA.
90

GHz band. The Act requires the report on the portion of the study on the 5.850-5.925 GHz band 

no later than 18 months after enactment (August 22, 2013). NTIA published in January 2013 the 

results of their initial study evaluating known and proposed spectrum-sharing technologies and 

the risk to Federal users if the FCC allows U-NII devices to operate in the 5.850-5.925 GHz 

band.160 The NTIA report identified a number of risks to FCC-authorized stations operating 

DSRC systems for ITS in the 5.850-5.925 GHz band and suggested mitigation strategies to 

explore.

On April 10, 2013, the FCC published in the Federal Register its NPRM to revise Part 15 

of its Rules to permit U-NII devices in additional portions of the 5 GHz spectrum, including the 

5.850-5.9250 GHz, so as to “increase wireless broadband access and investment.”161 While the 

FCC NPRM proposes permitting U-NII devices in the 5.850-5.9250 GHz band, DSRC, as the 

incumbent, would retain its primary allocation of the band – U-NII devices would have to 

operate on a non-interfering basis under the FCC Part 15 Rules.162 In June 2013, at the request of 

DOT, NTIA forwarded to the FCC the comments and concerns that DOT expressed relating to 

the deployment and protection of DSRC in the 5.850-5.925 GHz band.

The Institute for Electrical and Electronics Engineers 802 standards committee has 

established a working group, known as the IEEE 802.11 DSRC Coexistence Tiger Team, that 

provides an international multi-stakeholder technical forum that includes industry experts 

previously involved in developing standards for both wireless local area networks and vehicular 

wireless communications.163 While NTIA’s January 2013 5 GHz Report indicated that NTIA 

would follow up with quantitative studies in connection with domestic and international 

regulatory proceedings involving the 5350-5470 MHz, 5850-5925 MHz, and other bands, NTIA 

believes that industry participants should first be afforded adequate time to identify acceptable 

 

160 The NTIA 5 GHz Report is available at www.ntia.doc.gov/report/2013/evaluation-5350-5470-mhz-and-5850-

5925-mhz-bands.

161 78 Fed. Reg. 21320, at 21321 (Apr. 10, 2013).

162 One of the primary operating conditions under Part 15 is that the operator must accept whatever interference is 

received and must correct whatever interference is caused. Should harmful interference occur the operator is 

required to immediately correct the interference problem, even if correction of the problem requires ceasing 

operation of the Part 15 system causing the interference. See 47 C.F.R. Section 15.5.

163 In August of 2013, the Regulatory Standing Committee of IEEE 802.11 created a “Tiger Team” to bring together 

interested participants to exchange technical ideas and explore possible solutions to the band sharing issue as 

proposed in this NPRM. This group, referred to as the DSRC Coexistence Tiger Team, operates under the auspices 

of the IEEE 802.11 working group. Conference calls are conducted weekly, and submissions and emails are openly 

available to the public on IEEE document servers.
91

technology approaches for coexistence in the 5850-5925 MHz band. 164 The Tiger Team’s 

meetings have been productive, providing a venue for presenting and discussing concepts 

regarding potential coexistence approaches. On January 24, 2014, the Tiger Team sent a letter to 

the FCC to summarize activities coordinated by IEEE 802.11.165 As discussed in the letter the 

current work items for the group include:

• Review of ITS/DSRC field trials conducted to date

• Review of work to date on coexistence

• Presentations on use cases

• Presentation of possible coexistence approaches

• Modeling/simulation of possible coexistence approaches

• Prototype testing of candidate approaches 

Thus far, the group has engaged in extensive discussions about the status and performance 

of DSRC systems, explored requirements for band sharing, and had presentations on some 

preliminary candidate approaches for sharing techniques. If viable candidates for sharing are 

identified as part of this effort, NTIA anticipates extensive field testing will be conducted by 

WLAN and DSRC stakeholders outside of IEEE 802.11. 

While DOT is encouraged by the work of the Tiger Team, the candidate approaches

presented thus far do not yet contain adequate content to evaluate whether spectrum can safely 

be shared without creating harmful interference. As the work of the Tiger Team progresses and 

mature technical proposals are submitted for review, DOT will continue to work with the NTIA 

to review and analyze these sharing approaches.

166 Once this analysis is complete, DOT, along 

with the NTIA and the FCC, will be better positioned to assess how the proposed changes to 

existing rules and regulations for harmonization across such a large swath of spectrum will 

impact DSRC. NTIA and DOT will continue to work with the FCC to explore different avenues 

to facilitate and encourage inter-industry and inter-agency collaborative efforts to assess the 

possibility of sharing in the 5.850-5.925 GHz band.

 

164 Letter from Lawrence E. Strickling, Assistant Secretary for Communications and Information to the Honorable 

Anna Eshoo, Ranking Member, Subcommittee on Communications and Technology Committee on Energy and 

Commerce (Jan. 27, 2014).

165 The letter is available at https://mentor.ieee.org/802.18/dcn/14/18-14-0007-02-0000-dsrc-coexistence-tt-statusletter-to-oet.docx.

166 DOT submitted comments to the NPRM through NTIA in June 2013. See

http://apps.fcc.gov/ecfs/document/view?id=7022424618 (last accessed Jan. 28, 2014).
92

Research Need V-1 Spectrum Sharing Interference167

Research Activity: Effect of spectrum sharing on V2V Crash Avoidance Performance

Description: Evaluate the impact of unlicensed U-NII devices on the transmission and 

reception of safety critical warnings in a shared spectrum environment.

Target Completion: US DOT is working with NTIA and other stakeholders to evaluate sharing 

proposals made by the communications industry in order to help ensure 

that there will be no interference to DSRC-enabled V2V safety 

applications caused by any sharing of the spectrum with unlicensed 

devices.

Current or planned NHTSA research addressing this need:

US DOT will continue to coordinate with NTIA and other stakeholders on the issue of shared 

spectrum testing.

d) V2V wireless communication channels

Currently, 75 MHz of wireless spectrum is allocated for DSRC by FCC. This spectrum is 

divided into seven non-overlapping 10 MHz channels, plus a 5 MHz guard band at the beginning 

of the frequency range. The FCC band plan for this spectrum specifies particular usage, power 

limits, etc. for these channels as shown in Figure V-2 below.

 

167 Intelligent Transportation Systems: Vehicle-to-Vehicle Technologies Expected to Offer Safety Benefits, but a 

Variety of Deployment Challenges Exist (Nov. 2013, GAO-14-13). See www.gao.gov/assets/660/658709.pdf (last 

accessed Feb. 12, 2014).
93

Figure V-2 Band Plan for DSRC Channel Spectrum

Frequency

5.850

GHz 5.860

GHz

5.870

GHz

5.880

GHz

5.890

GHz

5.900

GHz

5.910

GHz

5.920

GHz

5.925

GHz

Uplink

Downlink

Ch 172 Ch 174 Ch 176 Ch 178 Ch 180 Ch 182 Ch 184

Public

Safety/

Private

Public Safety

Control Intersections

Channel

Public

Safety/

Private

Public

Safety/

Private

Control Med Rng Service Short Rng Service V-V Safety Intersections

Public

Safety/

Private

Public

Safety

V-V

40 dBm

33 dBm

23 dBm

40 dBm Power Limit 44.8 dBm

33 dBm Power Limit

23 dBm Power Limit

As a radio, the DSRC unit operates on one frequency (or “channel”) at a time – consider, 

for example, the AM/FM radio in vehicles today, which can receive one station or another

depending on how it is tuned (tuning being the act of shifting signal reception from one radio 

frequency to another), but does not receive clearly when it is between stations, and cannot be 

tuned to more than one frequency at once.

The current V2V operation uses two radios, one tuned to channel 172 and dedicated for 

safety communications and another tuned to channel 174 for security-related communications. In 

addition, a third channel, 178, is used as a control channel to manage channel switching168 to 

support messages on other channels related to other services/applications, such as mobility or 

environment.

Early on in the VSC-A project, researchers initially attempted to use channel 178 as both 

a “control” channel169 and for transmission of the BSM, but using a single channel for both 

unduly restricted BSM transmission, potentially hindering safety. It was thought that a channel 

switching mode could be used on a single radio to support the BSM as well as use the other

channels for other messages, because the channel switching mode would cause the BSM 

transmissions to switch from channel 178 to some other channel. However, because a radio can 

 

168 Channel switching is the use of a dedicated channel to route incoming messages to multiple “service” channels 

that use the incoming information. This method allow for a single radio to be used to support multiple functions.

169 The control channel “tells” the radio which channel to “listen” to for specific information as well as transmitting 

that same information when the device is ready to transmit information.
94

only transmit or receive on a single channel at a time, channel switching only solves part of the 

problem – the radio still has to take turns between the BSM and the other necessary messages.

The sections that follow explain the modes of operation and how the research indicated 

the need to implement a dedicated channel for the BSM.

(1) Channel Switching Mode

In order to transmit and receive messages on different channels, DSRC will have to 

switch from one channel to another, which it may need to do in order to perform different 

functions necessary for V2V communications.

Time is an important facet of V2V communications, because BSM transmissions need to 

be received in a timely manner in order to warn drivers of potential dangers in time for them to 

react, among other things. If DSRC is switching from one channel to another, it may experience 

a time lag as the next channel is being picked up, which may potentially affect receipt of 

important transmissions. The IEEE 1609.4 standard170 divides time for purposes of DSRC 

transmission into 100 millisecond sync intervals (the equivalent of 10Hz). The sync intervals are 

then sub-divided into a Control Channel (CCH) interval and a Service Channel (SCH) interval, 

and a time division mechanism is defined for a device to switch between the CCH and a SCH 

every 50 ms to transmit and/or receive DSRC messages.

As shown in Figure V-3 below, Channel 178 is designated as the “Control Channel.” It 

was originally envisioned that all vehicle and roadside units accessing this spectrum would use 

the control channel to determine what information is available on other channels, and then switch

to the other channels to access the information.171

 

170 For more information, see VSC-A Final Report: Appendix Volume 2. 171 Id.
95

Figure V-3 Time Division Channel Usage

During the VSC-A research initiative, vehicles participating in V2V safety 

communications using this channel switching operation sent and received BSMs on the CCH 

during the CCH interval. This would allow vehicles to participate in non-V2V safety 

communications on a SCH during the SCH interval for other DSRC services. While this safety 

communication model is not required by IEEE 1609.4, or any other standard, it was considered 

as the baseline approach for the initial research.

One of the main advantages of the above approach is that it allows a single-radio vehicle 

to participate in V2V safety by exchanging BSMs with its neighbors and also to avail itself of 

DSRC services that are offered during SCH intervals (e.g., by RSE). This capability is especially 

attractive as part of an initial DSRC deployment strategy to boost market penetration. One of the 

main disadvantages of this approach, however, is that safety messages are effectively limited to 

the CCH interval, and thus channel congestion is a significant concern. At high channel loads, 

the probability that two or more packets “collide” due to overlapping transmissions can become 

significant. As explained below, the research has indicated ways of mitigating the disadvantages, 

and NHTSA plans to do additional testing on congestion mitigation.

Due to a required 4 ms front guard interval V2V communications can only use a 

maximum of 46 ms out of the 100 ms sync interval. In other words, effectively only 46 percent 
96

“potentially” available bandwidth is available to be used because the remainder must be used for 

non-BSM transmissions, such as security, mobility, environment, and possibly commercial (auto 

diagnostics, requested assistance information) transmissions on other channels providing this 

information. Determining channel capacity via analysis is quite complex due to the MAC 

protocol used in DSRC. However, a simple calculation shows why 1609.4 time division causes a 

concern for V2V safety. As explained below, research indicates methods of addressing this 

concern are available. If a DSRC channel supports 6 Mbps, this is equivalent to 2,000 

messages/second for 3,000-bit messages (the approximate size of an average BSM). At 10 

messages/second/vehicle, this is equivalent to 200 vehicles in a given transmission region. With 

BSMs confined to the CCH interval, the capacity is cut to about 45 percent due to the guard 

interval and the need to complete packet transmissions before the start of the SCH interval. In 

this simple example, that is equivalent to 90 vehicles in a region. It is not difficult to construct 

realistic traffic scenarios in which a capacity of 90 vehicles in a transmission region represents a 

significant constraint.

(2) Multi-Channel Operation versus a Dedicated Safety Channel

Having two radios, one of which is always tuned to the dedicated safety channel, may 

help to avoid the need for channel switching and enable the vehicle to broadcast and receive 

BSMs the entire time it is in operation.

Having also determined that communication channel congestion could limit V2V safety 

system performance,172 the CAMP VSC-A project team analyzed 11 scenarios of one- and twochannel operational approaches, within the constraints of IEEE 1609.4. This is discussed further

in the Congestion Mitigation section of this paper – Section V.E.2.b). 

3. Interoperability performance requirements

This section of the paper discusses the performance requirements for DSRC, GPS, and 

other system components that are understood to achieve interoperability.173 This section covers 

four major topics: (1) overview of system performance requirements; (2) overview of 

requirements for exchanging messages (3) research history and technical maturity; (4) 

recommendations.

 

172 CAMP, VSC-A Final Report (Sept. 2011, Report No. DOT HS 811 492A). See

www.nhtsa.gov/DOT/NHTSA/NVS/Crash%20Avoidance/Technical%20Publications/2011/811492A.pdf (last 

accessed Jan 28, 2014). [Hereafter, “VSC-A Final Report”]. 173 This section provides a general discussion of performance requirements for DSRC and GPS. Requirements 

needed to support specific safety applications are discussed in Section VI.
97

a) Overview of V2V program system performance requirements

This section describes how the specifications were developed. It provides a top-level 

view of the major factors that influenced the development of performance requirements for the 

V2V system.

The following factors were taken into account in developing the V2V system 

performance requirements.

1. Connected Vehicle Model Deployment safety application characteristics

2. Transmitting power a DSRC radio could provide

3. Receiving ability at a given area with a given transmitting power

4. Language vehicles speak when they communicate with one another

5. Language used for communication between vehicles and RSEs

6. Information necessary to be included in the BSM

7. Information necessary to be included in the communication between vehicles and the 

infrastructure.

8. Media devices could use to carry messages when they communicate with one another

9. Media devices could use to carry messages when they communicate with RSEs

10. Basic Safety Message data accuracy needs to be specified

11. Error tolerance and error correction capability (considering potential distortion) of over 

the-air signals being received by OBE

12. Capability of the system to accommodate all communication within a given area of 

coverage and for a given number of vehicles (DSRC channel congestion mitigation)

13. Method of synchronizing communication system network

14. The method of verifying and validating messages from other vehicles

15. The method of verifying and validating messages from other ECUs in a vehicle itself

16. Security scheme to protect data communication

17. Security scheme to initiate and ensure trusted key establishment

18. Security scheme to support key management

19. Physical security to protect security components and elements that will be essential 

pieces of establishing and sustaining the network trust at the Infrastructure side

20. Physical security to protect security components and elements that will be essential 

pieces of establishing and sustaining the network trust on the on-board DSRC devices

21. Security scheme to protect Personally Identifiable Information (PII)

b) Research history and technical maturity/readiness

Following is a summary of related research findings on performance requirements for 

DSRC and interoperability, a list of references, and a table for cross referencing to research 

activities, reports, standards, and the current status.
98

Initial system performance requirements were defined during the VSC project that started 

in 2002 and ran until 2005. During the VSC project, the VSC Consortium developed an initial set 

of safety applications that could be improved by communications with sources outside the 

vehicle. The VSCC then estimated benefits in lives saved and injuries avoided of these 

applications. VSCC and DOT then selected a subset of those applications for further

development based on their potential safety benefits. VSCC developed communications 

performance requirements for the following eight applications.

• Traffic Signal Violation Warning

• Curve Speed Warning

• Rollover Warning

• Emergency Electronic Brake Lights

• Cooperative Forward Collision Warning

• Left Turn Assistant

• Lane Change Warning

• Stop Sign Movement Assistance

These requirements included the following.

• Message packet size of 200 to 500 bytes (all 8 scenarios)

• Maximum required range of communications of 50 to 300 meters 

(all 8 scenarios)

• One-way, point-to-multipoint broadcast messages (7 of 8 scenarios)

• Two-way, point-to-point messages (1 of 8 scenarios)

• Periodic transmission mode (6 or 7 of 8 scenarios)

• Event-driven transmission mode (1 or 2 of 8 scenarios)

• Allowable latency of 100 milliseconds (6 of 8 scenarios)

• Allowable latency of 20 milliseconds (1 of 8 scenarios)

• Allowable latency of 1 second (1 of 8 scenarios)174

The outcome of this project was, however, that the communications requirements would 

need further refinement as prototype vehicle safety applications are developed from a safetysystems design perspective.175

The extension of the VSC project, the VSC-A project, further refined and added to the 

minimum performance requirements. The VSC-A project developed performance requirements 

 

174 For more information, see Vehicle Safety Communications Project - Final Report (Report No. DOT HS 810 591)

at www-nrd.nhtsa.dot.gov/pdf/surplus/nrd-12/060419-0843/PDFs/MainReport.pdf (last accessed Jan. 28, 2014). 175 Id.
99

for GPS performance,176 warning repeatability, maximum warning latency, true and false 

positive warning rates, EEBL, FCW, BSW+LCW, DNPW, IMA, and CLW.177

The requirements were refined yet again in the V2V Interoperability project, known as 

V2V-I.178 These requirements were broken up into both functional (high-level) requirements and 

performance (detailed) requirements.179 The V2V-Interoperability Report contains design 

requirements for the on-board equipment (DSRC radio, GPS receivers, and processors). Some of 

the requirements that were developed during these projects have been worked into a number of 

IEEE and SAE standards. For further reference on the development of the standards, please see 

Section V.E.

The performance requirements that were used and implemented in the specification 

documents for the VADs and ASDs during the Safety Pilot Model Deployment were developed 

directly from the V2V-I Project. During the Model Deployment over 3,000 vehicles have been 

equipped with V2V and V2I technologies and are driving around the public roadways of Ann 

Arbor, Michigan. Sixty-four of these vehicles are equipped with integrated OEM solutions 

(CAMP-developed device) that have been fully integrated into the vehicles, 300 vehicles have 

aftermarket technology installed, and 2,850 vehicles are outfitted with vehicle awareness devices 

that can transmit the BSM to other vehicles but cannot receive information with which to alert 

the driver. Many of these systems have internal components designed and built by a number of 

different manufacturers and suppliers. These vehicles have been operating together, as a system, 

providing alerts and advisories to drivers as a representation of how a fully functional V2V

system might work. While this is a research project, and is built using prototype hardware, the 

performance requirements are adequate to ensure system functionality – i.e., the vehicles are 

capable of communicating with each other. The identified requirements are based on working 

systems that were collaboratively developed between NHTSA and CAMP, but since they are 

 

176 The VSC-A project performance requirement for GPS were further refined during the GPS available study. For a 

discussion of the performance requirements for GPS, see: Section V.D.1.d) “Relative Positioning.” 177 For more information, see VSC 2 Consortium, “Vehicle Safety Communications – Applications (VSC-A) Final 

Report: Appendix Volume 1 System Design and Objective Test,” (Sept. 2011, Report No. DOT HS 811 492B) at

www.nhtsa.gov/Research/Crash+Avoidance/Office+of+Crash+Avoidance+Research+Technical+Publications (last 

accessed Jan. 28, 2014) [Hereafter, “VSC-A Project Appendix Volume 1”]; see also VSC-A Project Appendix 

Volume 2 for full system requirements and further information. 178 The critical system requirements were published prior to the Safety Pilot Model Deployment as the VAD and 

ASD system specifications. See System Requirements Description, 5.9 GHz DSRC Vehicle Awareness Device 

Specification, Version 3.6 (Jan. 25, 2012) at www.its.dot.gov/newsletter/VAD%20Specs.pdf (last accessed Jan. 28, 

2014) and System Requirements Description, 5.9 GHz DSRC Vehicle Awareness Device Specification, Version 3.6

(Dec. 26, 2011) at www.its.dot.gov/meetings/pdf/T2-05_ASD_Device_Design_Specification_20120109.pdf (last 

accessed Feb. 20, 2014).

179 The critical requirements can be found in sections 4 and 5 of System Requirements Description, 5.9 GHz DSRC 

Vehicle Awareness Device Specification, Version 3.6 (Jan. 25, 2012) at

www.its.dot.gov/newsletter/VAD%20Specs.pdf (last accessed Jan. 28, 2014) 
100

based on non-production systems, the agency does not consider them finalized, recognizing that 

at more work is necessary as discussed earlier in this section before production-level deployment 

can be realized. The following table shows a summary of the high-level requirements, including 

the maturity of the performance requirements that have been employed in the V2V program 

research. The table also shows the range of different research projects from which the Safety 

Pilot performance requirements were leveraged.

Table V-6 Performance requirements used in V2V research

Requirement Research

Activities

Requirements 

Exist

for Safety Pilot

Finalized

Under

Development Comments

Safety application

requirements

VSC, VSC‐A,

V2V‐I, Safety

Pilot

  Application compliance test

procedures, BSM Min Performance

Req./SAE J2945

DSRC transmission

range

VSC, VSC‐A,

V2V‐I, Safety

Pilot

  e.g., 300 meters, 360 degrees, BSM

Min Performance Req./SAE J2945

DSRC receiving range VSC, VSC‐A,

V2V‐I, Safety

Pilot

  e.g., 300 meters, 360 degrees, BSM

Min Performance Req./SAE J2945

Language vehicles speak

when they communicate

with one another

VSC, VSC‐A,

V2V‐I, Safety

Pilot

  communication protocol SAE

J2735, IEEE 1609.2 and IEEE

1609.3 and IEEE 1609.4

Language used for

communication between

vehicles and RSEs

VSC, VSC‐A,

V2V‐I, Safety

Pilot

  communication protocol

IEEE 1609.2 and IEEE 1609.3 and

IEEE 1609.4

Information necessary to

be included in the V2V

communication

VSC, VSC‐A,

V2V‐I, Safety

Pilot

  BSM protocols; SAE J2735, BSM

Min Performance Req./ SAE J2945

Information necessary to

be included in the 

communication between

vehicles and RSEs

VSC‐A, V2V‐I,

Safety Pilot

  WSM Protocols; IEEE 1609.3 &

1609.4

DSRC radio channel

operational mode and

usage for communication

with other vehicles

VSC, VSC‐A,

V2V‐I, Safety

Pilot

  IEEE 1609.4, BSM Min

Performance Req./ SAE J2945

DSRC radio channel

operational mode and

usage for communication

with RSEs

VSC, VSC‐A,

V2V‐I, Safety

Pilot

  IEEE 1609.4, BSM Min

Performance Req./ SAE J2945

Basic Safety Message

data accuracy needs to be

specified

V2V‐I, Safety

Pilot

  BSM Minimum Performance

Requirements/SAE J2945

Error tolerance and error

correction capability

(considering potential

distortion) of over the air

signals being received by

OBE

VSC‐A, V2V‐I,

Safety Pilot

  IEEE 802.11p

Ability of the system to

accommodate all

communication within a

given area of coverage

and for a given number

of vehicles (DSRC

channel congestion

mitigation)

VSC‐A, V2V‐I  DSRC channel congestion

mitigation research will continue

beyond 2013 decision

Method of synchronizing

communication system

network

VSC‐A, V2V‐I,

Safety Pilot

  GPS (UTC) time; BSM Min

Performance Req./ SAE J2945
101

Ability to verifying and

validating messages from

other vehicles

VSC‐A, V2V‐I,

Safety Pilot

 

Method of verifying and

validating messages from

other on‐board ECUs

(within a given vehicle.

E.g., vehicle data bus)

Need for plausibility checks, data

bus security is under consideration

Security scheme to

protect V2V

communication

VSC, VSC‐A,

V2V‐I,

V2V‐CS, V2V‐

VSCS, Safety

Pilot

  Prototype SCMS design

Security scheme to

initiate and ensure

trusted key establishment

VSC, VSC‐A,

V2V‐I,

V2V‐CS, V2V‐

VSCS, Safety

Pilot

 

Security scheme to

support key management

VSC, VSC‐A,

V2V‐I,

V2V‐CS, V2V‐

VSCS, Safety

Pilot

 

Physical security to

protect security

components and elements

that will be essential

pieces of establishing

and sustaining the 

network trust at the 

Infrastructure side

V2V‐CS,

V2V‐VSCS

Physical security to

protect security

components and elements

that will be essential

pieces of establishing

and sustaining the 

network trust on the 

on‐board DSRC devices

VSC, VSC‐A,

V2V‐CS,

V2V‐VSCS

in planning

Security scheme to

protect Personally

Identifiable Information

(PII)

V2V‐I,

V2V‐CS,

V2V‐VSCS,

Safety Pilot

 

c) Software performance requirements

Research is needed to determine if the software components that NHTSA may require as 

part of an FMVSS can be regulated using objective tests, without requiring the use of specified 

algorithms. NHTSA has not previously regulated system aspects as detailed as software 

components. This may be necessary because a performance test may allow multiple pathways to 

compliance but may not result in full interoperability among devices. Because software can 

allow for multiple methods of producing the same result, there is a gap in our understanding of 

how potential multiple software solutions by different device manufacturers (or vehicle 

manufacturers) would affect the V2V system’s ability to be interoperable.

As an example, congestion mitigation has currently been tested during the V2V-I project 

using two different mitigation algorithms. These algorithms were specified under the system 

requirements and units were fielded with these predetermined algorithms. They worked well and 

predictably under all test scenarios because all software components were the same. Had they
102

instead been performance metrics such as “the channel busy ratio must stay below 70 percent at 

all times,” we do not know if different suppliers would have developed individual mitigation 

solutions and whether they would be interoperable. There is a risk that if different suppliers were 

to use different mitigation strategies, vehicles may not receive BSMs with the frequency needed 

for the safety applications to function.
103

Research Need V-2 Impact of Software Implementation on DSRC Device Performance

Research Activity: DSRC Device Performance Requirements

Description: Finalize requirements for V2V device software standards, performance, 

and requirements needed to ensure interoperability with other vehicles and 

roadside equipment, support safety applications, and adhere to security 

and privacy communications requirements.

Target Completion: Mid-2015 (draft report to NHTSA)

Current or planned NHTSA research addressing this need:

Working with both industry (CAMP) as well as independent (third-party) automotive and 

communications research companies, NHTSA is developing a complete description of 

functional, performance, and operational requirements for the on-board vehicle systems needed

to support V2V communications.

d) Additional performance requirements research

Current performance requirements exist in a pre-competitive, prototype research state. 

We have been able to achieve a large scale (2,800 vehicles) test in which vehicles could reliably 

talk to each other, yet these requirements are not FMVSS-ready given that test procedures to 

gauge compliance with the requirements do not exist for all components of the system.

Additionally, test procedures that do exist have not been evaluated to ensure that they produce 

objective, repeatable results, and minimum requirements necessary for some components of 

system such as the minimum broadcast frequency of the BSM necessary to support safety 

applications have yet to be determined.

NHTSA is currently engaged in research with Booz Allen Hamilton180 to examine the 

minimum performance measures for DSRC communication and system security. This research 

will include functional and performance requirements for the DSRC device and present NHTSA 

with a list of recommended changes to these requirements as currently laid out for the Safety 

Pilot Model Deployment. An example of these recommendations would be how to deal with endof-life issues on the DSRC components and security system.

In order to participate in the V2V system, the current design assumes that V2V devices 

will carry up to three years of security certificates. It is possible that V2V devices may retain 

these certificates upon their retirement. If the certificates were somehow obtained by a malicious 

 

180 NHTSA Task Order DTFH61-11-D-00019-T-13016 DSRC Communications Performance Measures.
104

party, they could be used to participate in the system without permission. To maintain the 

security of the system, some requirements for device end-of-life (e.g., forced memory purging of 

certificates, destruction of a malfunctioning or non-functional device, or some other end-of-life 

measure) will likely be necessary in exchange for participation in the SCMS, although it remains 

to be determined whether such requirements would be from NHTSA or from the entity managing 

the SCMS.

Research Need V-3 DSRC Data Communication System Performance Measures

Research Activity: DSRC Device Performance Requirements

Description: The purpose of this research is to finalize the operational modes and 

scenarios, key functions, and qualitative performance measures that 

indicate minimum operational performance to support DSRC safety and 

security communication functions.

Target Completion: Mid-2015 (draft report to NHTSA)

Current or Planned NHTSA research addressing this need:

The research to be completed under Need IV-2 will also address this research need.

Once performance requirements have been identified, objective performance metrics to 

measure those requirements will need to be developed to support FMVSS-level testing. NHTSA 

should be able to leverage the certification testing work used to support the Safety Pilot, although 

performance testing conducted for the Safety Pilot will need to reflect any changes the 

performance requirement research may suggest.

Research Need V-4 Development of Safety Application Test Metrics and Procedures

Research Activity: Safety Application Objective Test Procedures & Performance 

Requirements

Description: This research will take the performance measures and objective test 

procedures used during the research of V2V applications and develop 

FMVSS level performance measures and safety application objective tests.

Target Completion: 2016 (draft test procedures)

Current or Planned NHTSA research addressing this need:

CAMP, NHTSA, and the Volpe Center are completing projects to address the development of 

objective test procedures for IMA and LTA safety applications. This research activity will 

include investigation of the rationale for and validation of various performance measures; test the 

practicability and need for non-ideal conditions testing; and evaluate the applicability of the tests 

to V2V based or V2V/Vehicle-based sensor combined systems. 
105

E. System Limitations

1. What are the known system limitations for V2V communication?

V2V safety systems use messages broadcast by vehicles to enable cooperative crash 

warning applications. Traditional crash warning applications, on the other hand, use vehiclebased radar, lidar,181 mono camera, stereo camera or combinations of these sensors to perform 

similar threat detection in order to enable crash warning applications. Each sensor has unique 

characteristics that translate into system advantages and disadvantages. This section discusses 

system limitations of V2V safety systems by comparing their characteristics to those of 

traditional crash warning systems. The discussion is based on the information summarized in the 

following table.

Table V-7 Collision Avoidance Sensor Summary

Sensor Type Radar

24 GHz

Radar

77GHz

Lidar Mono 

Camera

Stereo 

Camera

Radar + 

Camera

V2V

Field of view 560 180 270 360 480 180/360 3600

Typical range 60 m 200 m 10 m (50 m) (150 m) 200 m /

50 m

300 m

Accuracy 0.2 m 0.2 m 0.2 m ? ? 0.2 m /

?

< 1.5 m

Relative reliability 

in snow, fog, heavy 

rain

Reliability in direct 

sun and shadows

Reliability in 

“urban canyons”

Reliability in 

tunnels and under 

heavy foliage

Vulnerability to 

damage or 

misalignment

Yes Yes Yes No No yes No

Generally 

considered 

sufficient to react to 

no No No no yes yes Yes

 

181 Lidar detects distant objects and determines their position, velocity, or other characteristics by analysis of pulsed 

laser light reflected from their surfaces. (Lidar operates on the same principles as radar and sonar.)
106

fixed objects (by 

OEMs)

Number of objects 

(vehicles) that can 

be 

tracked/processed 

at any given time

17 17 17 ? ? 17/? TBD

>200

Capable of close 

range, low speed 

range-rate estimates 

(city safe capability

No No Yes No No No for 

warning 

applicati

ons only

Requires multiple 

vehicles to be 

equipped

No No No No No No Yes

Supports pedestrian 

detection

need 

multisensor 

system

need 

multisensor 

system

need 

multisensor 

system

need 

multisensor 

system

yes yes TBD

Sufficient to 

support activation 

of active safety 

systems

No No No No yes yes TBD

a) Field of view and range limitations

The figures below illustrate a generic traffic scenario for both a conventional crash 

avoidance system and a V2V-based safety system. Assuming all vehicles are equipped with 

V2V, the orange vehicle in Figure V-4 receives messages from the other vehicles in a 360o area 

bound by a 300 meter radius, enabling safety applications that monitor the entire surroundings 

for crash imminent threats. The conventional system shown in Figure V-4 includes forwardlooking long range radar and mono camera, as well as short range radar on each rear corner for 

blind zone detection. The forward sensor fields of view are illustrated by the blue shading, which 

depicts the long-range radar, and the white shading, which depicts the mono camera. The white 

shading at each rear corner depicts the short-range blind spot radars. As illustrated, the forwardlooking radar can be obstructed by the first vehicle directly ahead in its lane, and thus is often 

unable to track other vehicles in the same lane. Similarly, the camera can be obstructed by 

objects such as the commercial truck in the illustration. With the four sensors shown, the 

conventional system is limited to reliably detecting and monitoring only two of the vehicles 

shown, the vehicle directly in front and the vehicle in the blind zone at the rear left of the 

equipped (orange) vehicle. By contrast, the V2V system can warn of threats from any direction 

using a single GPS sensor and DSRC communications.
107

Figure V-4 V2V System

Figure V-5 Conventional System
108

b) System availability limitations

V2V system availability degrades gracefully182 when subjected to reduced GPS 

availability (e.g., urban canyons or under extremely heavy foliage) or prolonged GPS outages 

(tunnels). In its current state, the V2V safety system is relatively immune to intermittent GPS 

outage (less than 1 second), which accounted for the majority (93%) observed during the 20,000 

miles of data collected in the DOT-CAMP system performance testing.183 Prolonged outages of 

2 to 5 seconds result in graceful degradation of the system (safety applications), potentially 

limiting the applications to only those that require road-level positioning accuracy (e.g., 

intersection movement assist) and not allowing those that require lane-level accuracy (e.g., 

forward collision warning).

c) Basic safety message congestion limitations

Large scale deployment of V2V safety communications will require a communication 

system that will function and be able to support interoperability even when penetration of V2V 

into the vehicle fleet becomes widespread. There will be situations during normal driving 

conditions where a large volume of vehicles are driving in close proximity to each other, such as 

heavy freeway traffic. It will be important to ensure that the volume of messages in such 

“congested” situations does not somehow compromise the effectiveness of the system (and thus 

the effectiveness of the safety applications that might be enabled by the system) by saturating 

devices with messages, making it difficult to quickly sort out which are safety-critical and which 

are not, or even to transmit in general.

Testing of the scalability of the communications network has been conducted under two 

main projects, the Vehicle Safety Communications – Applications project184 and the V2V-

 

182 Fault tolerance, or graceful degradation, is the property that enables a system to continue operating properly in 

the event of the failure of (or one or more faults within) some of its components. If its’ operating quality decreases at 

all, the decrease is proportional to the severity of the failure, as compared to a naïvely designed system in which 

even a small failure can cause total breakdown. 183 Vehicle-to-Vehicle Safety System and Vehicle Build for Safety Pilot (V2V-SP) Final Report, Vol. 2: 

Performance Testing (Crash Avoidance Metrics Partnership on behalf of the Vehicle Safety Communications 3 

Consortium, April 10, 2014). See: Docket No. NHTSA-2014-0022 184 VSC-A was a 3-year collaborative effort between DOT and CAMP to develop and test communications-based 

vehicle safety systems to determine if DSRC at 5.9 GHz, in combination with vehicle positioning, can improve upon 

autonomous vehicle-based safety systems and/or enable new communications-based safety applications. The VSC-A 

project also developed performance requirements for GPS performance, warning repeatability, maximum warning 

latency, true and false positive warning rates, Emergency Electronic Brake Lights, Forward Collision Warning 

(FCW), Blind Spot Warning and Lane Change Warning (BSW+LCW), Do Not Pass Warning (DNPW), Intersection 

Movement Assist (IMA), and Control Loss Warning (CLW). See VSC-A Project Appendix Volumes 1 and 2 for full 

system requirements and further information. See also: Vehicle Safety Communications – Applications (VSC-A), 

Second Annual Report, January 1, 2008 through December 31, 2008 (Report No. DOT HS 811 466) at

www.nhtsa.gov/Research/Crash+Avoidance/Office+of+Crash+Avoidance+Research+Technical+Publications (last 

accessed Jan. 28, 2014).
109

Interoperability project.185 During VSC-A, 60 vehicles were tested for scalability of the network 

to see the effects of different data rates, multiple radios, and broadcast frequencies. The V2V-I 

project tested a grouping of 50, 100, 150, and 200 vehicles under a number of different V2V 

safety applications in multiple testing locations across the country.

As a point of reference, Figure V-6 shows the interchange between I-495 and Rt. 66 

outside of Washington, DC. This interchange contains 2 express lanes and 4 regular lanes for I495 running north and south and passing underneath Rt-66, which has 3 lanes running east and 

west. When off ramps are added, this leads to a total of 22 lanes of traffic in a 300 m radius. In 

grid-lock conditions, assuming an average car takes 24 ft. of lane space, this interchange can 

have over 800 vehicles in range of a single radio. The agency is conducting additional congestion 

research to better understand congestion limits and mitigation needs.

Figure V-6 I-495 & Rt 66 Interchange

Also tested during the V2V-I project were two algorithms for congestion mitigation.186

These algorithms are designed to limit the frequency of BSMs broadcast during periods of high 

 

185 More information can be found in Interoperability Issues of Vehicle-to-Vehicle Based Safety Systems Project -

V2V-Interoperability, Draft Final Report, Section 4.2 (April 17, 2014). (Hereafter, “V2V-I Final Report”). See 

Docket No. NHTSA-2014-0022. 186 Algorithm X is a transmission control protocol for scalable V2V safety communications that supports adaptive 

control of the message transmission rate and transmission power. Algorithm Y controls message transmission rate

based on reported CBP from the neighboring vehicles and that measured by the host vehicle. The algorithm adapts 
110

channel usage and at the same time ensure that vehicles were able to receive sufficient data to 

support the safety applications.187

Also developed under the V2V-I project was a proof of concept simulator designed to 

numerically simulate large vehicle networks. The V2V-I project found that even during the 200 

vehicle test, at the maximum normal transmit rate of 10 Hz, the channel was not saturated, and 

all safety applications tested functioned normally. Although channel saturation was not reached, 

both congestion mitigation algorithms were able to demonstrate decreasing channel congestion 

while showing good safety application performance.188

Current research has shown that the V2V safety applications perform reliably in test 

scenarios with up to 200 vehicles in communication range. However, research conducted by 

CAMP and NHTSA has yet to estimate the number of other DSRC-equipped vehicles that a 

single DSRC radio would need to be exposed to in an environment (such as heavy freeway 

traffic) where channel congestion would be significant. Because the number of vehicles using the 

network within a particular broadcast area is not known, it is therefore not possible to compare 

the results of this testing to levels of channel congestion that might be experienced after full

penetration of the technology.

Channel congestion may impact DSRC’s effectiveness, which may in turn impact the 

effectiveness of DSRC-supported safety applications. Congestion mitigation may, therefore, be 

an issue that the agency needs to consider in developing potential future regulatory requirements 

for DSRC. NHTSA has planned additional research on this subject to address that need.

d) Relative positioning limitations

Based on testing during the initial phase of the Safety Pilot Model Deployment of several 

different GPS receivers of varying performance, quality and price, NHTSA believes that off the 

shelf, automotive GPS receivers on the market today are able to perform very well in V2V 

applications, although that statement should be qualified. GPS availability and solution accuracy 

deteriorate, for example, in deep urban environments and other areas of limited sky coverage.

This will cause lane-level accuracy to degrade towards road-level accuracy in driving 

environments with limited sky visibility. While most of the safety applications require lane-level 

accuracy, and would thus be unavailable in those situations, road-level accuracy still allows the 

use of EEBL and IMA applications in these GPS-challenging locations. Any final determinations 

regarding the necessary performance for GPS units will be informed by the final results of the 

 

the message rate up and down in order to maintain a desired level of channel utilization. For more information, see: 

V2V-I Final Report Section 4.2 and Appendix A, V2V Safety Communications Scalability Algorithms Details. 187 V2V-I Final Report, at 79. 188 V2V-I Final Report, at 79.
111

Safety Pilot, Driver Clinic system performance, and other ongoing research. Additionally, the 

deployment of new satellites, navigation industry improvements, and collaboration between the 

navigation industry and the automotive industry will improve GPS receiver accuracy and identify 

ways to address current challenging GPS environments.189

It should be noted that GPS receiver performance in the market is quoted in terms of the 

absolute positioning accuracy. The BSM minimum performance requirements for the vehicle 

positioning are currently phrased in terms of accuracy to an absolute position for purposes of the 

Safety Pilot, requiring the vehicle’s reported latitude and longitude to within 1.5 meters of the 

actual position.190 A relation must be made between the relative positioning performance 

required by the V2V safety applications and the receivers’ advertised absolute positioning 

performance.

e) Comparison to sensor-based system

The V2V safety system communications is not impacted by weather (rain, fog, snow, 

sunlight or shadows). Radar and lidar perform reliably under all lighting conditions, while 

camera systems have some issues with shadows and lighting transitions, which are typical 

conditions for tunnels and under foliage during daylight. Additionally, V2V safety system 

communications are impaired by limited sky visibility, as in highly dense urban areas. In 

contrast, various conventional crash avoidance sensors perform reliably in urban canyons. In 

summary, both V2V safety systems and conventional crash warning systems have system 

availability limitations.

(1) Other Limitations for Conventional Sensor-based Systems

• Vulnerability to misalignment from impact (lidar and radar)

• Insufficient to react to stopped objects with a single sensor (lidar and radar)

• Limited number of vehicles can be processed (tracked) for threat determination

• Incapable of close range, low speed range-rate estimates (radar, camera)

(2) Other Limitations for V2V Safety Systems

• Requires a significant number of vehicles to be equipped for system effectiveness

• Accuracy is currently only sufficient for collision warning applications (see relative 

positioning section for future positioning improvements in Section V.E.1.d)

 

189 Intelligent Transportation Systems: Vehicle-to-Vehicle Technologies Expected to Offer Safety Benefits, but a 

Variety of Deployment Challenges Exist (Nov. 2013, GAO-14-13). See www.gao.gov/assets/660/658709.pdf (last 

accessed Feb. 12, 2014).

190 System Requirements Description: 5.9 GHz DSRC Vehicle Awareness Device Specification (Version 3.6, Jan, 

25, 2012). See www.its.dot.gov/newsletter/VAD%20Specs.pdf (last accessed Jan. 28, 2014), requirement number 

SRD-USDOTOBE-003-ReqPOS003v001: Vehicle Position.
112

• Additional testing and field experience needed to establish level of trust of V2V

messages sufficient to activate vehicle control applications

2. Potential mitigation strategies for known system limitations

a) System availability

For short duration GPS outages lasting a few seconds, devices can make use of inertial 

navigation units to predict the location of the vehicle. These units contain a number of 

accelerometers, gyros, and angular rate sensors that can be combined with mathematical models 

of vehicle dynamics to take the vehicle’s position at loss of GPS and estimate the position further 

for a few seconds. Because of noise and error build-up in the sensors, the accuracy of the 

estimated position degrades the longer the estimation runs. Currently there are no long-term 

solutions for extended-duration GPS outages.

b) Basic Safety message congestion

Future research is currently planned under an extension of the V2V-I project, currently 

known as V2V-IE (phase 2). During this phase, physical testing will be conducted using up to 

400 DSRC devices, both in vehicles and in specially-designed static test carts. This second phase 

will also work to refine the simulation, calibrating it against the data recorded during the first 

phase of the V2V-I project and data recorded during the field testing in phase 2. The goal of the 

simulation work is to simulate vehicle interactions far more numerous than what the agency 

believes can be practically field-tested. Following both the field testing and simulation work, the 

algorithms initially tested in phase 1 of the V2V-I project will be refined using the data collected 

during each. Finally, as the project closes, findings will be incorporated into SAE J2945 and 

other applicable SAE standards, which will facilitate development of devices that contain 

standardized congestion mitigation capability.

Research Need V-5 BSM Congestion Sensitivity

Research Activity: Basic Safety Message Congestion Mitigation

Description: Complete congestion mitigation and scalability research to identify 

bandwidth congestion conditions that could impair performance of safety 

or other applications, and develop appropriate mitigation approaches.

Target Completion: Early 2015 (draft report to NHTSA)

Current or Planned NHTSA research addressing this need:

Analysis, research and testing of potential congestion challenges and mitigation strategies will be 

completed by CAMP under the existing Interoperability task.

Additionally, NHTSA believes that a DSRC channel congestion mitigation algorithm is 

important to ensure that the system identifies the most critical threats in densely populated traffic 
113

scenarios (assuming all equipped with V2V), to avoid missed threats and consequent risk to 

drivers.

c) Relative positioning improvements

Improvements to GPS signals and industry plans to produce automotive-grade receivers 

capable of using these signals will allow for increased positional accuracy in the future. The 

relationship between the specified absolute positioning performance of a receiver and its required 

relative positioning when measured against a different receiver needs to be better understood, 

and the study relating these two will lead to a more informed positioning performance 

requirement for V2V systems.

Given the observed differences in relative positioning performance in mixed pairs of 

receivers, such a relationship will need to be generalized for different receivers. CAMP has 

proposed, as part of Task 5 of the Vehicle-to-Vehicle Safety System Light Vehicle Builds and 

Model Deployment Support, a course of research to derive this relation. The path outlined in the 

proposal included a literature search for any previously-found relationships between relative and 

absolute positioning; an analysis of CAMP’s previously-collected test data that includes both 

relative and absolute positioning, such as the Safety Pilot Performance Testing, and additional 

data collection activities. This additional data collection will expand the diversity of receivers 

from what is found in the literature search and from previous CAMP testing. The goal of this 

data collection and analysis will be to produce a generalized relationship between relative and 

absolute positioning for the receiver pairs tested.

Research Need V-6 Relative Positioning Performance Test

Research Activity: Definition of Certification Requirements and DSRC Device Test 

Procedures

Description: Research will be required to determine how to test relative positioning 

performance across GPS receivers produced by different suppliers and 

yield a generalized relationship between relative and absolute positioning.

Target Completion: Onboard requirements (mid 2015), and draft test procedures (late 2015).

Current or Planned NHTSA research addressing this need:

NHTSA is investing in developing the equipment and procedures to test adherence to 

communication standards and performance requirements (including relative positioning) as 

outlined in J2945 and other standards.

The additional data collection CAMP is proposing as part of the relative positioning 

requirement definition offers an opportunity to evaluate the peculiarities of positioning 

performance observed during the Safety Pilot performance testing. These short periods (several 

minutes) of erroneous position were observed at particular geographic locations and were 

attributed by CAMP to particular combinations of vehicle and GPS receiver having differing 
114

positional biases. The testing of a wider range of different receivers will allow for the 

opportunity to observe these types of peculiarities, and a more informed assessment of their 

effect on positioning performance.

CAMP has additionally proposed collaborative work between them and the GPS 

suppliers to improve receiver performance for V2V safety. Using the GPS industry’s expertise 

with CAMP’s experience with V2V safety, this collaboration plans to identify improvements that 

could be made to the supplier’s existing GPS hardware and software, further studying the effect 

of mixed receivers on relative positioning performance, and gaining a better understanding of 

tuning receivers explicitly for V2V applications leading towards the goal of a upgrading 

automotive grade GPS receiver.191

Research Need V-7 Vehicle and Receiver Positioning Biases

Research Activity: Interoperability Research

Description: Research to understand potential erroneous position reporting due to 

positional biases across multiple GPS receiver combinations.

Target Completion: 2014 (Published final reports)

Current or Planned NHTSA research addressing this need:

Recent work has been completed as part of Phase I of the NHTSA-CAMP V2V Interoperability 

project and FHWA-CAMP Light Vehicle Driver Acceptance Clinics Project System 

Performance Test task. The final reports are under publication review and should be published in 

CY14. Additional research is being performed in Task 5 of the FHWA-CAMP Light Vehicle 

Build and Model Deployment Support Project. The final report is expected to be published in 

early CY2015. The research findings will be reflected in CAMP’s draft submission to the SAE 

J2945 subcommittee. No additional research is planned. 

3. Device installation constraints and requirements

a) OEM Devices

OEM devices are likely to be installed during the construction of the vehicle. This results 

in fewer constraints on installation than other V2V devices require. Basic constraints should 

include GPS antenna location and offset (the antenna should be located in an area of the vehicle 

that is free of electro-magnetic interference and allows for an unobstructed view of the sky), and 

location of the transceivers (they should be located in an area of the car free of EMI that does not 

interfere with the transmission or reception of the BSM or security information). Since the 

 

191 Vehicle-to-Vehicle Safety System Light Vehicle Builds and Model Deployment Support (V2V-MD), Technical 

Proposal, Vol. 1 Statement of Work (Crash Avoidance Metrics Partnership on behalf of the Vehicle Safety 

Communications 3 Consortium, Feb, 15, 2012). See Docket No. NHTSA-2014-0022.
115

devices will be integrated into the vehicle, care needs to be taken not to overly restrict the 

manufacturer’s ability to select internal locations for supporting hardware.

b) Aftermarket Devices

The agency believes a certified installer would likely be needed to complete the 

installation for aftermarket safety devices. It is imperative that all V2V components be properly 

installed to ensure that an aftermarket device functions as intended. Whereas some vehicle 

owners may choose to replace their own brakes or install other components on their vehicles 

themselves, installation requirements for ASDs will likely not be conducive to a do-it-yourself 

approach. Improper installation of a GPS antenna has the potential to affect V2V 

communications for that vehicle via false warnings, improperly timed warnings, etc. An 

improperly installed aftermarket device may put all other V2V-equipped vehicles it encounters at 

risk until the given vehicle stops communicating, or until its messages are rejected for 

misbehavior. After completing the installation into the vehicle, correct configuration settings for 

x, y, z offsets are critical for system operation.

4. Managing device updates and improvements

a) OEM Devices

OEM devices allow for a variety of different methods for upgrades and improvements 

due to their integrated nature. These devices will be integrated into the vehicle data bus, which 

will allow them to make use of the same methods that OEMs currently use to manage vehicle 

firmware updates. OEMs also have a large distribution network, allowing for a pre-existing 

pathway for vehicle owners to have a reputable entity upgrade vehicle-specific DSRC software 

updates. A similar method can be leveraged to renew security credentials and service 

misbehaving units.

OEM devices can also leverage the current methods of upgrade that existing consumer 

electronics use today. A smartphone connected to the car via Bluetooth, or acting as a mobile 

hotspot, can be used to wirelessly update security certificates. Also, built-in DVD and Blu-ray

players in existing infotainment systems might serve as a physical method of installing upgrades 

and new security credentials. Lastly, any method used to upgrade software components in 

aftermarket devices can be leveraged to upgrade OEM devices as well.

b) Aftermarket Devices

There are a range of methods from the consumer electronics industry that can be used to 

provide updated applications, certificates, etc., for aftermarket safety devices. These include:

• Wi-Fi Access, Satellite

• Cellular Access

• Flash or SD Memory Card
116

An ASD could receive updates in virtually the same way that cell phones, tablets, and 

laptops acquire updates – by connecting the device to a Wi-Fi network and downloading any 

updates or improvements over the Internet or satellite. Alternatively, an ASD could use a cellular 

connection to a back office server. The main challenge with this approach is determining how to 

cover the cost of the data transferred over the cellular provider network. One solution would be 

to link the device to the owner’s personal cell connection. A third way for an ASD to receive 

updates is to use a flash or SD memory card. This approach was used in the Safety Pilot Model 

Deployment when software updates were required for VADs and self-contained devices. This 

approach is somewhat analogous to using a DVD to update the GPS maps in OEM or 

aftermarket navigation systems. Security certificates could also be downloaded from a computer 

to the memory card and then loaded to the device.

F. Global activities and differences in V2V systems

1. Research and/or implementation of V2V communications in other regions

Significant V2V research and development activities are underway in both Europe and 

Asia. For Asia, Japan and Korea appear as the regional leaders for development leading to 

eventual production implementation. Europe has made clear statements toward implementing 

V2I mobility-focused applications by the 2015 timeframe.

2. Differences between the current U.S. regional vision and other regions

a) Comparison of U.S. to EU

The U.S. approach focuses on a core set of crash-critical V2V safety applications. In 

previous research conducted by the U.S. DOT under the Vehicle Infrastructure Integration (VII) 

Program, the major focus was V2I applications and establishing an infrastructure. The shift in 

primary focus to vehicle-based V2V applications facilitates implementation of ITS safety 

technologies without the costly infrastructure implemented through State and local government 

investment while achieving safety benefits at overall lower costs. While the EU has defined 

crash-critical safety applications as well, the priority in the EU is driver safety advisories (not 

safety-critical warnings), driver support messages (such as eco-driving), and commercial 

applications such as insurance.192 The breadth and content of EU applications, including mobility 

applications, reflects their market-driven approach, whereas the V2V safety focus in the U.S. 

reflects the potential for reducing crashes.193 In the EU standards development activities 

encompass a broader set of applications while DOT is primarily focused on developing standards 

 

192 Global V2X Deployment: Contrasts with U.S. Approach, at 35 (Bishop, Jan. 21, 2013) at Docket No. NHTSA2014-0022 193 Id.
117

to support V2V crash avoidance applications.194 Release 2 of the ETSI standards, planned for 

2017, will focus on crash avoidance.

European carmakers have committed to begin introducing DSRC systems in 2015 and it 

is likely that initial European introductions would be on high-end vehicles and/or newly redesigned vehicle models; a different approach than requiring DSRC on all vehicles. While initial 

introduction in Europe could come much sooner than the U.S., the number of equipped vehicles 

could grow faster after the initial start in the U.S., if the U.S. pursues a DSRC mandate for all 

new vehicles. However, vehicles deployed initially in Europe would address mobility, 

sustainability, and “soft” safety on “day one” for equipped vehicles, while the U.S. approach to 

address crash-critical safety in the initial deployment and to provide a framework for other areas, 

such as mobility and others would be more challenged to give benefits on “day one.” Therefore

the benefits obtained in the first years of deployment will be quite different between the U.S. and 

other regions of the world. Additionally, because the focus in the EU for DSRC systems is 

mobility and environment rather than safety, which primarily entails communications between 

vehicles and infrastructure rather than between vehicles, security is much less of a concern, and 

it is likely that DSRC mobility and environment applications can be rolled out without the need 

for a SCMS. This would eliminate the SCMS cost from DSRC implementation in the EU, 

although that would change if the EU was to move towards requiring DSRC-based safety 

applications. However, the current European model would entail infrastructure costs that are not 

envisioned in the initial stages of V2V implementation in the U.S.

In terms of spectrum allocation, the U.S. allocation calls for seven channels of 10 MHz 

each (a total of 75 MHz of spectrum located in the 5.85 to 5.925 GHz frequency band), with one 

channel designated as a control channel and one channel exclusively for safety. The EU 

allocation calls for the 5.875-5.905 MHz band to be designated for safety-related ITS functions 

with three 10 MHz channels, including the possibility of two additional channels being granted 

in the future. No control channel exists in the EU approach.

Activities on the infrastructure side in Europe are promising for a deployment 

corresponding to OEM introductions, but this is not a certainty. Advances in ITS have typically 

been fragmented and slow due to the EU Member States being sovereign nations. EasyWay, a 

major ITS deployment initiative sponsored by the European Commission, which supplements 

deployment funding at the national level, has published a Cooperative-ITS Roadmap aiming at 

2017 deployment of V2X. In addition, the Amsterdam Group aims at 2015 deployment. Given 

these concerns, European Commission officials at the 2012 ITS World Congress noted they are 

 

194 Id.
118

discussing various instruments that could apply to deployment, such as incentives to road 

operators or cities.195

b) Comparison of United States to Asia

In Asia, Japan and Korea are most active in DSRC development, with Japan leading. In 

both countries, the initial focus is on adapting the Electronic Toll Collection system operating at 

5.8 GHz. The Japanese government has deployed 5.8 GHz “ITS Spots,” which communicate 

with electronic toll tags to offer limited V2X safety capabilities, as well as mobility and 

convenience services. Additionally, some Japanese automotive OEMs (mainly Toyota) are 

actively supporting the deployment of V2X using 760 MHz communications. Japan appears 

likely to proceed with a two-band solution, and suppliers have prototyped transceivers covering 

both bands. Deployment of 760 MHz systems could come as soon as 2014.

In China, this band is reserved for potential ITS use as well. There have been indications 

that Korea seeks to shift to 5.9 GHz to be more compatible internationally, but no 

announcements have been made. No information was discovered indicating any interest from 

China for ITS applications in the 5.9 GHz band.

Development of message sets in Japan is not yet complete but appears to be toward the 

BSM/CAM196/DENM197 message sets. Harmonization of probe data message sets is currently 

underway between Japan and the U.S. Similar to the approach in Europe, deployment in Japan is 

mostly market-driven, with the government leading to provide initial roadside capability in the 

case of the 5.8 GHz system, and some OEMs pushing for the 760 MHz system for V2V crash 

avoidance.

The Japanese 5.8 GHz system is not compatible with the IEEE 802.11p protocol used in 

the U.S. and Europe, due to a Japanese law requiring legacy protocols. At the security level, 

there are advocates of using IEEE 1609.2 as the security framework, which would be compatible 

with the U.S. and Europe, but this has not yet been decided.

 

195 Id., at 39. 196 Cooperative Awareness Message. 197 Decentralized Environmental Notification Message.
119

VI. V2V Safety Applications

NHTSA reviewed the existing information on various safety applications that leverage 

V2V communications and on various driver-vehicle interface options. NHTSA’s goal in this 

effort was to determine:

• The extent to which the available performance and test metrics cover the variety 

of circumstances under which crashes occur that V2V-based safety applications 

could address; and

• Whether the metrics are practicable, repeatable, objective, and can clearly 

distinguish systems that pass from those that fail.

A. Performance metrics currently available for V2V safety applications

There are a number of performance and test metrics currently available that can be used 

to evaluate the performance of the research-stage prototype V2V safety applications and 

systems. This information can provide a useful foundation for the agency to consider and build 

upon to potentially establish Federal Motor Vehicle Safety Standards.

While the existing performance and test metrics cover the main conditions under which 

each of these crash types occur, a common theme among the performance metrics for all of the 

applications is the lack of testing under all conditions within the context of the safety problem, 

including, for example, poor weather or road conditions. To move forward with regulatory action

to mandate safety applications, the agency would need to understand whether performance and 

test metrics can take into account these less-than-ideal conditions. As an example, the safety 

problem contains crashes that occur on wet pavement, which increases vehicle stopping 

distances, requiring adjustments to when advisories or warnings would be provided to a driver:

advisories or warnings should be provided sooner if more time is needed for the driver to 

respond or for the vehicle to perform. However, this would need to be balanced with the 

potential for advisories or warnings to become nuisances to the driver, which could reduce 

system benefit.

With this in mind, the agency will need to evaluate crash statistics further to better 

understand what percentage of crashes happen under less-than-ideal conditions and how 

potential adjustment to warning activation may help drivers. Current crash data indicates that 

most crashes happen under ideal conditions, but further analysis may yield opportunities that 

could be addressed by V2V technology. This research would also focus on providing clear 

rationales for the inclusion or exclusion of any performance and test metrics.
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In addition to considering how the existing performance and test metrics could be refined, 

further development will help ensure the metrics are practicable, repeatable, and can clearly 

distinguish systems that conform to the performance metrics from those that do not.

B. The safety applications

This section focuses on the following V2V safety applications that address common rearend, opposite direction, junction crossing, and lane change crash scenarios, as shown in Table 

VI-1 and described below:

Table VI-1 V2V Safety Applications

Crash Type Safety Application

Rear-End Forward Collision Warning (FCW)

Electronic Emergency Brake Light

Opposite direction Do Not Pass Warning

Left Turn Assist (LTA)

Junction crossing Intersection Movement Assist (IMA)

Lane change Blind Spot Warning +

Lane Change Warning (BSW+LCW)

• FCW: Warns the driver of an impending rear-end collision with another vehicle ahead in 

traffic in the same lane and direction of travel.

• EEBL: Warns the driver of another vehicle that is braking hard farther up ahead in the 

flow of traffic. The braking vehicle does not necessarily have to be in the direct line of 

sight of the following vehicle, and can be separated by other vehicles.

• DNPW: Warns the driver of one vehicle during a passing maneuver attempt when a 

slower-moving vehicle, ahead and in the same lane, cannot be safely passed using a 

passing zone that is occupied by vehicles in the opposite direction of travel. The 

application may also provide the driver an advisory warning that the passing zone is 

occupied when a passing maneuver is not being attempted.

• LTA: Warns the driver of a vehicle, which is beginning to turn left in front of a vehicle 

traveling in the opposite direction, that making a left turn, at this time, would result in a 

crash.

• IMA: Warns the driver when it is not safe to enter an intersection due to high collision 

probability with other vehicles at controlled (with stoplights) and uncontrolled (with stop, 

yield, or no signage) intersections.

• BSW + LCW: Warns the driver during a lane change attempt if the blind spot zone into 

which the driver intends to switch is, or will soon be, occupied by another vehicle 

traveling in the same direction. The application also provides the driver with advisory 
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information that another vehicle in an adjacent lane is positioned in the original vehicle’s 

“blind spot” zone when a lane change is not being attempted.

C. Key Findings for each V2V Safety Application

1. Forward Collision Warning

Forward Collision Warning is an application that currently has well-developed researchlevel performance and test metrics. The agency’s analysis identified where more information 

would be needed to fully explore the issues that could arise in a regulatory action regarding V2V 

safety applications, such as a supporting rationale that clearly explains the safety risk/crash 

scenario that each metric is designed to address and how the metric will address that 

risk/scenario. Test metrics have been developed by CAMP and have been further refined by 

Volpe in support of the Track 4A Forward Collision Avoidance project. Test metrics for nonV2V forward collision systems were also developed for NHTSA’s New Car Assessment 

Program (NCAP) and the In-Vehicle Based Safety Systems (IVBSS) project. Many of these 

performance and test measures may be applicable to a V2V-based FCW application; however, 

additional metrics will need to be developed based on V2V’s unique capabilities, such as the 

DSRC radio operating in inclement weather and being able to detect vehicles beyond the current 

capabilities of radar and visual sensors.

The test procedures for FCW developed by CAMP and Volpe address all three of the 

priority pre-crash scenarios included in the rear-end crash group: Lead Vehicle Stopped, Lead 

Vehicle Decelerating, and Lead Vehicle Moving. These three scenarios comprise 93 percent of 

the rear-end crashes. Additionally, several of the test scenarios developed address variations of 

the striking maneuver crash scenario, which, while comprising a small number of rear-end 

crashes, represents an incremental benefit that can be gained by a V2V-based FCW system.

While not explicitly tested, the FCW application also has the potential to address the additional 

two Lead Vehicle Accelerating scenarios, which comprise the other 7 percent of the rear-end 

crash group

However, additional analysis is necessary to ensure that each performance and test metric 

is sufficiently supported by a clear rationale. The specifics of these test procedures, such as their 

required alert timing, speeds at which the test is run, and radius of curvature, vary in detail across 

the developing organizations, and the agency believes they may need to be further refined to 

better reflect the safety problem.
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2. Emergency Electronic Brake Lights

Emergency Electronic Brake Light addresses the Lead Vehicle Decelerating scenario and 

shares some overlap in functionality with the Forward Collision Warning application. EEBL 

issues a warning to the driver when the lead vehicle is decelerating by a minimum of 0.4 g.

Previous research indicated that relatively severe braking (0.55 g or higher) by the lead vehicle in 

LVD crashes accounts for approximately 15 percent of the total number of LVD crashes.198

3. Do Not Pass Warning

The agency found that the Do Not Pass Warning application currently has a less robust 

set of performance and test metrics compared to other V2V safety applications studied. Do Not 

Pass Warning addresses only a subset of opposite direction crashes because it addresses 

situations where the driver is intentionally conducting a passing maneuver using the lane of 

opposing traffic. The safety data indicate that the vast majority (approximately 90 percent) of 

opposite direction crashes occur when a driver unintentionally drifts into a lane with oncoming 

traffic (as opposed to drivers conducting a passing maneuver). The current design of the DNPW 

application, however, issues a warning to the driver only when the driver activates his turn signal 

when changing lanes.

The current test metrics that are available also do not test the DNPW application’s ability 

to function under a wide variety of roadway conditions (e.g., under various road curvatures 

which may exceed the capabilities of the path prediction algorithm). For example, as 25 percent

of the opposite direction crashes resulting from a passing maneuver do occur under varying 

roadway conditions, the currently-available test metrics may need to be altered or supplemented 

in order to test for those conditions.

4. Left Turn Assist (LTA)

Left Turn Assist is an application that addresses left turn across path/opposite direction 

crashes that constitutes approximately 7.4 percent of all light vehicle crashes. Recent research 

suggests that while executing a turn, drivers activate the turn signal about 75 percent of the 

time.199 Current performance and test metrics for LTA require turn signal activation to activate 

the safety application. Although the research has suggested potential methods to predict left turns 

without an active turn signal, either (1) the application will need more development to predict 

 

197 Analyses of Rear-End Crashes and Near-Crashes in the 100-Car Naturalistic Driving Study to Support RearSignaling Countermeasure Development (Lee, Llaneras, Klauer, & Sudweeks, 2007, Report No. DOT HS 810 846). 

See www.nhtsa.gov/DOT/NHTSA/NRD/Multimedia/PDFs/Crash%20Avoidance/2007/Analyses%20of%20RearEnd%20Crashes%20and%20Near-Crashes%20(DOT%20HS%20810%20846).pdf (last accessed Mar. 4, 2014). 199 Turn Signal Usage Rate Results: A Comprehensive Field Study of 12,000 Observed Turning Vehicles (Ponziani, 

2012, SAE Technical Paper 2012-01-0261). See http://papers.sae.org/2012-01-0261/ (last accessed Jan. 29, 2014).
123

left turns without a signal or (2) this information should be used to discount the estimated safety 

benefits of this application when turn signal activation is the only indication of driver intent.

However, there is some risk that relying on driver intent may produce false warnings 

resulting from the ambiguities of determining driver intent to execute a left turn. Finally, more 

testing would be required to ensure the values are tuned to the optimal values to determine when 

to provide imminent or advisory warnings compared to the current metrics. Further testing and 

tuning may potentially minimize false warnings. The OEMs understand that the current 

configuration of LTA that requires turn signal activation to indicate driver intent limits the 

application’s effectiveness. As indicated above, the OEMs agree that more development is 

needed to ascertain driver intent not only for LTA but for other crash avoidance applications. 

However, various OEMs have indicated that this work is OEM-specific and each will investigate 

other methods to ascertain driver intent to support their individual safety applications. 

5. Intersection Movement Assist (IMA)

Intersection Movement Assist has the potential for significant safety benefits and cost 

savings. As designed, IMA should address five types of junction-crossing crashes. These crashes, 

which collectively represent 26 percent of all crashes occurring in the crash population and 23

percent of comprehensive costs, can be categorized as follows: straight crossing paths at nonsignal, left turn into path at non-signal (LTIP), right turn into path at signal (RTIP), running red

light, and running stop sign.

Initial Safety Pilot Model Deployment results indicated there is opportunity for this 

application to issue false warnings in a real-world environment. Various roadway geometries 

(e.g., cloverleaf, on-ramp, exit ramp) that do not represent a crash-imminent situation can be 

incorrectly classified as conflict situations by the system. Improvements to the IMA algorithm 

for the second stage of driver evaluations indicate these false warnings can be improved as the 

algorithms mature through additional testing. It may be necessary to develop new performance 

and test metrics that are designed to mitigate false warnings on different roadways such as 

curved roads and at non-perpendicular intersections.

6. Blind Spot +Lane Change Warning

Blind Spot Warning/Lane Change Warning is an application that provides an advisory 

alert when another vehicle occupies the adjacent lane in the driver’s blind spot. This advisory 

elevates to a warning when the driver signals his intent to change lanes through the activation of 

the turn signal. An advisory is not elevated to a warning if a driver unintentionally drifts into an 

adjacent lane, i.e., does not indicate intent by activating a turn signal. Additionally, drivers 

infrequently use turn signals in lane change near-crash events (<26 percent turn signal use, based 
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upon an unpublished analysis of IVBSS data).200 As a result, the application has the potential to 

address at least 19 percent of the crashes in the lane change crash group.201

D. Key conclusions for each application

1. Forward Collision Warning

Current FCW applications based on visual and radar detection systems can be stymied by 

certain lighting and weather conditions, and are limited with respect to distance. FCW 

applications using V2V technology can function in environments and under conditions beyond 

the current visual and radar detection systems (e.g., sunrise, sunset, rain, snow, >300m range), 

allowing for a more robust warning system. Some further refinement of performance and test 

metrics is advisable to align V2V-based FCW applications better to the safety problem, and to 

more clearly specify each of those metrics with a supporting rationale. With further development 

of the performance and test metrics, potentially greater safety benefits can be realized with a 

V2V FCW application, or a combined V2V and sensor-based system, as compared to visual or 

radar-based systems without V2V.

2. Blind Spot Warning + Lane Change Warning

BSW/LCW is an application that provides an advisory alert when another vehicle 

occupies the adjacent lane in the driver’s blind spot. This advisory elevates to a warning (LCW) 

when the driver signals his intent to change lanes through the activation of the turn signal.

As discussed, lane change maneuvers can be either purposeful or accidental, and they

may or may not involve use of the turn signal. In order to cover the variety of potential crash 

situations, it is recommended that other indicators of driver intent and vehicle movement be 

identified in addition to the turn signal, as well as ways of measuring them for use in a LCW 

application. Finally, the test metrics established to evaluate these systems need to test the LCW 

when vehicles are traveling at varying speeds between the host vehicle and remote vehicle to 

align more closely with the safety need.

3. Do Not Pass Warning

Do Not Pass Warning has the potential to reduce crashes that are not easily addressed by 

the limited detection range and line of sight capabilities of radar or camera systems. Incremental 

safety benefits can be realized from Do Not Pass Warning alone; however, as currently designed 

 

200 Data provided by Dr. W. Najm in 5/3/13 email, based upon analysis of IVBSS data. See Docket No. NHTSA2014-0022 201 Depiction of priority light-vehicle pre-crash scenarios for safety applications based on vehicle-to-vehicle 

communications (Najm, Toma, and Brewer, 2013, Report No. DOT HS 811 732). See:

www.nhtsa.gov/Research/Crash+Avoidance/ci.Office+of+Crash+Avoidance+Research+Technical+Publications.pri

nt (last accessed Jan. 29, 2014).
125

with reliance on turn signal activation and with functional limitations under certain road 

conditions (e.g., road curvatures), the application’s benefits may not be as large as those from 

other applications. As an addition to a suite of other V2V safety applications, DNPW may be 

useful for realizing safety benefits at little marginal cost.

However, when only considering this smaller portion of opposite direction crashes the 

DNPW application has the potential to be well-suited for addressing this crash problem because 

V2V communications afford vehicles a rich set of information (e.g., position and trajectory) 

regarding the other vehicles on the road over a long distance.

DNPW could offer improved range over sensor-based systems and it may be advisable to 

investigate fused V2V and sensors systems and their ability to address DNPW-related crash 

situations.

4. Left Turn Assist

Left Turn Assist addresses the majority of crashes at intersections in which the turning 

vehicle is using the left turn signal. As stated above, research suggests that approximately 75

percent of drivers use turn signals when executing turns. Although previous research202 efforts 

have suggested potential methods to predict left turns without an active left turn signal, either (1) 

the application will need more development to develop prediction techniques or (2) the benefits 

for this application must be discounted when turn signal activation is the only indication of 

driver intent.

It may be advisable for LTA to also consider yaw rate and steering wheel angle along 

with turn signal activation, heading, and vehicle speed to help determine driver intent and

whether to issue a warning. However, these additions could affect the implementation of 

aftermarket safety devices.

Overall, a driver’s failing to activate turn signals when making left turns is the largest 

limiting factor to the effectiveness of this application, reducing the number of crashes this 

application could potentially address by 1.9 percent. The proper formulation of performance 

metrics needs to consider all real-world driving situations that can be addressed by the LTA 

application. If performance metrics cannot address certain real-world conditions, we may not be 

 

202 The Time Course of a Lane Change: Driver Control and Eye Movement Behavior (Salvucci and Liu, 2002, 

Transportation Research, Part F, 5(2): 123-132). See

http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.73.2172&rep=rep1&type=pdf (last accessed Jan. 29, 

2014); also See Modeling Differences in Behavior Within and Between Drivers (Liu, 2011) in Human Modeling in 

Assisted Transportation: Models, Tools and Risk Methods, in 15-22 (Cacciabue, Hjälmdahl, Lüdtke, Riccioli, Eds., 

2011) at http://mvl.mit.edu/MVLpubs/MVL_10.10_Liu_HMAT2010_Springer.pdf (last accessed Jan. 29, 2014).
126

able to claim that the systems meeting those tests can address the safety risks of those real-world 

conditions.

5. Emergency Electronic Brake Light

Emergency Electronic Brake Light addresses the Lead Vehicle Decelerating scenario and 

shares some overlap in functionality with the Forward Collision Warning application. EEBL 

warnings could improve through the use of additional information, such as lane-level 

information, street-level information, roadway geometry and elevation, etc. EEBL operation 

could be revised to include different scenarios not covered by FCW that could provide distinct 

benefits for EEBL compared to other applications.

6. Intersection Movement Assist

Intersection Movement Assist has the potential to address each of the crash types for realworld junction crossings. As currently implemented, the application does not issue a warning and 

the test metrics do not test for warnings under certain circumstances, such as when a vehicle 

entering an intersection is moving at low speeds. The analysis of the currently-available research 

has uncovered a number of limitations of the performance and test metrics.

The current test procedures should be modified to reflect a greater range of speeds and a 

greater variety of road geometry configurations, particularly non-perpendicular intersections, 

curved roads, and overpasses (a false positive test) to allow for extended safety benefits to be 

claimed for these crashes. A wider range of testing, especially at higher speeds (representing 

real-world crash speeds), will require the development of safer protocols that reduce or eliminate 

the consequences of a crash during testing, such as using remote guided targets as opposed to 

real vehicles.

7. False warning improvement research

The agency has determined that additional research to mitigate false positive warnings for 

the V2V safety applications identified above would be beneficial. If false positive warnings are 

perceived as annoying by the driver, user acceptance could decline, and driver response to true 

warnings might be negatively affected. This research need has been identified and work is 

underway to establish the research plan and conduct the necessary investigation to determine 

how to improve upon the performance of V2V safety application advisories and warnings 

through mitigating false positives.

The opposite of a false positive alert is a false negative alert. False negative alerts are also 

referred to as missed alerts. A missed alert occurs when two equipped vehicles are in an 

imminent crash situation and the associated safety application does not issue an alert. Missed 

alerts may result in a crash occurring that could have been avoided.

Missed alerts will be analyzed as part of the Safety Pilot Model Deployment. A 

preliminary FCW missed alert analysis was conducted using the first 6 months of data. The 
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analysis identified seven possible no-alert situations that mimicked other FCW alerts situations.

After further analysis of the time-to-collision, and when the subject applied the brakes; none of 

the situations represented a missed alert. Given the analysis was limited to a single safety 

application and only used the first 6 months of data, additional analysis using the full Safety Pilot

Model Deployment data set will need to be completed before a determination can be made 

concerning the disposition of V2V missed alerts.

Research Need VI-1 False Positive Mitigation

Research Activity: Evaluation of False Positive Warning Reduction Remedies

Description: Assess the capability and capacity of possible refinements to reduce 

frequency of false positive warning while maintaining crash avoidance 

effectiveness.

Target Completion: 2016 (draft report to NHTSA)

Current or Planned NHTSA research addressing this need:

NHTSA will leverage knowledge and experience gained during the Safety Pilot to develop 

various false-positive tests that exercise the ability of the DSRC-based safety systems to discern 

real threats from non-threat situations. 

8. Performance measures improvement research

The agency also identified several areas where performance measures could benefit from 

additional research for each V2V safety application. This research need has been identified and

work is underway to establish the research plan and conduct the necessary investigation to 

determine how to improve upon the performance of V2V safety applications.

The systems included in the Safety Pilot Model Deployment were designed to meet only 

limited CAMP test specifications and performance requirements. Accordingly, it is possible that 

fewer false positive warnings may have been observed during the Model Deployment if those 

same systems were designed to meet all of the test scenarios specified by CAMP and/or those 

covered by additional research testing (e.g., Track 4, IVBSS).

Research Need VI-2 Safety Application Performance Measure Rationale

Research Activity: Safety Application Objective Test Procedures & Performance 

Requirements

Description: Develop a rationale to support each performance and test metric 

recommended for incorporation into an FMVSS.

Target Completion: 2016

Current or Planned NHTSA research addressing this need:

A component of developing certification level Safety Application Objective Test Procedures 

(included in the Research Need V-4 activities previously described).
128

Research Need VI-3 Practicability of Non-Ideal Driving Condition Testing

Research Activity: Safety Application Objective Test Procedures & Performance 

Requirements

Description: Evaluate test variations for non-ideal driving conditions (e.g., curved 

roads, turn signal use, weather, oblique intersections) and develop a 

rationale supporting the inclusion or exclusion of those test conditions.

Target Completion: 2016 (draft report to NHTSA)

Current or Planned NHTSA research addressing this need:

A component of developing FMVSS level Safety Application Objective Test procedures 

(included in the Research V-4 activities previously described).

Research Need VI-4 Fused and Non-Fused V2V Safety Application Test Procedures

Research Activity: Safety Application Objective Test Procedures & Performance 

Requirements

Description: Develop test procedures that can be applied to systems relying solely on 

V2V information as well as “fused” systems, those relying on both V2V 

and other sources of information (e.g., on-board sensors).

Target Completion: 2016

Current or Planned NHTSA research addressing this need:

A component of developing FMVSS level Safety Application Objective Test procedures 

(included in the Research V-4 activities previously described).

Research Need VI-5 Performance and Test Metric Validation

Research Activity: Safety Application Objective Test Procedures & Performance 

Requirements

Description: Conduct test validation to ensure that the performance and test metrics are 

objective, repeatable, and practicable.

Target Completion: 2016

Current or Planned NHTSA research addressing this need:

A component of developing FMVSS level Safety Application Objective Test procedures 

(included in the Research V-4 activities previously described).

As a part of the agency’s research, it is prudent to have real-world validation of the 

performance and test metrics. In other words, we would ideally have some data to indicate that 

systems meeting the agency’s final performance requirements and test procedures in a potential 

FMVSS will address the safety problem as anticipated in the real world. This research need 

includes many components that are described above and capture in one comprehensive research 
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activity, “Safety Application Objective Test Procedures & Performance Requirements” that has 

been previously described via Research Need V-4.

E. Driver-vehicle interface

While the current research-based performance and test metrics developed to evaluate the 

V2V safety applications are relatively robust, they do not focus on the driver-vehicle interface 

(DVI); an area that provides challenges not only for V2V safety but for many facets of vehicle 

safety devices and applications. The collaborative V2V research efforts of both CAMP and 

Volpe did not include the DVI as a research topic. Further, the Safety Pilot Model Deployment 

research was not designed to analyze and compare the different aspects of the various DVIs and, 

overall, the effect that specific aspects of the DVI have on safety benefits has not been clearly 

defined and quantified.

Other available research, such as the NHTSA Crash Warning Interface Metrics and 

Human Factors Connected Vehicle research projects, should yield results to help inform how the 

agency could proceed with more explicit guidelines or, potentially, standards for V2V DVIs.

However, current available research does not yet have a method to evaluate the effectiveness of 

these DVI characteristics or to delineate a minimum standard for these characteristics. As a 

result, the DVI currently does not have performance or test metrics. Some characteristics of the 

DVI have research data to suggest ranges of potential performance metrics. However, these 

metrics were not determined considering the safety problem or a representative sample of U.S. 

drivers. Questions such as what are the best DVIs for particular safety applications and whether 

DVIs should be standardized for all vehicle types and manufacturers have not been answered.

Research Need VI-6 DVI Minimum Performance Requirements203

Research Activity: V2V DVI Safety Application Study (Mini-Sim- multiple sites) and V2V 

DVI Characterization Study

Description: Determine DVI’s impact on effectiveness of system and safety benefits 

applications to establish minimum performance for crash avoidance and 

objective test procedures.

Target Completion: 2015

Current or Planned NHTSA research addressing this need:

This research need is being addressed by several existing projects that will result in the 

Development of DVI minimum performance requirements for various DVI characteristics.

 

203 Intelligent Transportation Systems: Vehicle-to-Vehicle Technologies Expected to Offer Safety Benefits, but a 

Variety of Deployment Challenges Exist (Nov. 2013, GAO-14-13). See www.gao.gov/assets/660/658709.pdf (last 

accessed Feb. 12, 2014).
130

A potential regulatory action on V2V safety applications would not necessarily need to 

prescribe all elements of the DVI. However, at least some requirements (e.g., timing of the 

warning) are necessary not only to ensure that the DVI can effectively assist the driver in 

reacting appropriately to a crash-imminent warning, but also to ensure that warning requirements 

can be objectively evaluated.

F. Summary of major recommendations concerning safety applications

1) Conduct additional analysis to ensure that each performance metric is supported 

by a clear rationale (i.e., explain the safety risk/crash scenario that each metric is 

designed to address and how the metric will address that risk/scenario). The 

agency may need to conduct additional research to refine and validate the existing 

performance and test metrics against a variety of conditions under which crashes 

can occur.

a) Consider the inclusion of non-V2V sources of information (radar, camera, 

etc.) in the development and validation process for performance and test 

metrics, and how to handle their operation if they co-exist on a subject 

vehicle.

2) Conduct additional research and analysis on Driver Vehicle Interface warning 

characteristics that can effectively enable drivers to react appropriately and avoid 

the crash.

a) This research should consider the safety problem and a representative 

sample of U.S. drivers. The goal of this research should be to identify 

minimum DVI characteristics that are necessary.

b) This research should also consider whether multiple warnings/alerts can 

occur under real-world driving conditions, how frequently they might 

occur, and whether it is appropriate to consider methods for prioritizing 

those warnings to ensure that drivers are able to interpret the warning.

3) Consider whether regulatory action on various aspects of the V2V system 

can/should be conducted independently (e.g., separate FMVSSs covering 

communications protocol/basic safety message and the available applications).

4) Conduct additional research to determine the minimum basic safety message 

broadcasting range and frequency that are necessary to support each V2V safety 

application. The minimum BSM range and frequencies found in this research 

would need to be considered in the implementation of a message congestion 

mitigation strategy (Sections V.E.1.c) and V.E.2.b) ).

G. System compliance and enforcement

The Safety Pilot played a critical role in helping the agency to begin to understand what

V2V system compliance and enforcement strategies and procedures might be necessary if the 

agency decided to proceed with rulemaking to require V2V technology. “Standing up” the Safety 
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Pilot environment, for example, required conducting informal certification and compliance 

activities to ensure that participating devices were interoperable and that safety applications were 

functioning according to the specifications developed for the pilot activity.

However, the kinds of compliance obligations that vehicle (and V2V device) 

manufacturers could face if NHTSA did proceed with rulemaking for V2V would likely be much 

more rigorous than anything faced by participants in the Safety Pilot. V2V devices must be

interoperable in order for a V2V system to work properly; safety applications will not be 

effective if messages are not transmitted and received correctly. Assuming that the agency did 

decide to proceed with rulemaking, a standard requiring DSRC devices in all new vehicles would 

likely specify in detail (perhaps with some incorporation by reference of relevant parts of IEEE 

and SAE standards, which we would assume would be improved by that time to address the 

issues discovered during the Safety Pilot, etc.) exactly what specifications all related devices 

would have to meet. The agency recognizes that additional research and development is required 

to develop those specifications and accompanying test procedures, although we expect that much 

of the work completed to stand up the Safety Pilot can be leveraged as a foundation.

Research Need VI-7 Compliance Specifications and Requirements

Research Activity: DSRC Device Performance Requirements, and Test Procedures

Description: Development of performance requirements, test procedures, and test 

scenarios to evaluate a device’s compliance with interoperability 

standards, security communication needs; and to support safety 

applications. 

Target Completion: Onboard requirements (mid 2015), and draft test procedures (late 2015). 

Candidate performance requirements, test procedures, and test scenarios 

identified (late summer of 2015).

Current or Planned NHTSA research addressing this need:

The research need is addressed through activities previously described under Research Needs V2 and V-3. This research will identify the initial level of performance requirements, test 

procedures, and test scenarios that will facilitate evaluating the compliance of DSRC devices.

Once NHTSA establishes a FMVSS, vehicle and device manufacturers would be required 

to certify that they comply with it in order to sell vehicles and devices. Non-compliance with a 

FMVSS could result in enforcement action by NHTSA (e.g., a requirement to recall affected 

vehicles and devices, an injunction from selling affected vehicles and devices until remedied, 

civil penalties). Additionally, if V2V devices develop a safety defect, manufacturers (both of 

vehicles and V2V devices) may also be subject to a recall. It is possible that manufacturers may 

choose to rely on some kind of third-party certification for V2V devices to ensure uniform 

adherence to NHTSA’s requirements, but NHTSA would not expect to participate in that 

certification.
132

NHTSA may need to conduct further research into how to ensure that all V2V devices 

subject to a recall can be located, given the possibility that some devices may be mobile and go 

from vehicle to vehicle or owner to owner. Section VIII.B.3 discusses the possibility that for 

vehicles manufactured with V2V devices installed, the SCMS may be able to create a link at the 

time of manufacture between specific installed V2V devices or production lots of devices and 

enrollment certificates that later may help vehicle manufacturers and NHTSA identify defective 

V2V equipment. NHTSA worked with CAMP to identify and document alternative approaches 

that could be implemented to link device batches to enrollment certificates. However, it is not yet 

clear how such a linkage would be created for V2V devices that are not installed by the 

manufacturer, an important enforcement matter for NHTSA should the standards include 

aftermarket equipment.
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VII. Public Acceptance

A. The importance of public acceptance

The Safety Act requires that FMVSSs issued by the agency be practicable, and an 

important part of that consideration is whether the public is expected to accept and correctly use 

the technologies installed in compliance with the standard. According to the case law, a standard 

issued by the agency will not be considered practicable if the technologies installed pursuant to 

the standard are so unpopular that there is no assurance of sufficient public cooperation to meet 

the safety need that the standard seeks to address.204 Crash avoidance technologies in general, 

and V2V in particular, are new to consumers, and new technologies that can dramatically change 

the driving experience always have the potential to raise public acceptance issues. For V2V 

technologies, the extent to which the public understands and embraces the enhanced level of 

safety (and other mobility and environmental benefits) made possible by a V2V environment 

will need to outweigh the risks to individual privacy, actual or perceived, introduced by these

technologies. Additionally, as a practical matter if not a legal one, industry acceptance and 

cooperation may be equally important, should NHTSA take steps to regulate V2V technologies 

via FMVSS, particularly since NHTSA is hopeful that industry will play a central or supporting 

role in establishing key components of the SCMS, which is required to support deployment of 

V2V technologies.

1. Potential key aspects of consumer acceptance for V2V communication

a) Enhanced levels of safety

V2V technologies can potentially provide considerable safety benefits, but consumers are 

more likely to accept V2V technologies quickly if they understand how vehicles with this 

technology can be safer. Crash avoidance technologies play, at first glance, a more abstract role 

in keeping consumers safe than crashworthiness features. If a driver avoids a crash, it may be 

difficult for the driver to detect whether it was the driver’s own skill or the on-board technology 

that actually “saved” them, as compared to a crashworthiness technology like air bags, which 

clearly deploy to protect the driver and occupants in a crash. Consumers who cannot clearly see 

benefits to V2V technologies could be more tentative in their acceptance of V2V for longer than 

they might be with other safety technologies. Performing outreach to educate consumers on the 

safety benefits of V2V technologies, as well as on the privacy-protection methodology built into 

the V2V communications system, will likely be helpful to improving consumer acceptance, 

should the agency move forward with regulation. Some possible methods of public outreach 

 

204 Pac. Legal Found. v. Dept. of Transp., 593 F.2d 1338, 1345-46 (D.C. Cir.), cert. denied, 444 U.S. 830 (1979).
134

include working with industry to produce and air Public Service Announcements (PSAs) and 

conducting publicly-accessible – and media-covered -- technology demonstrations with V2Venabled vehicles nation-wide.

Preliminary research from the auto industry, however, seems to indicate that at least some 

members of the public would be interested in V2V-type technologies on their vehicles. On June 

5, 2013, at the Telematics Detroit Conference, the Alliance of Automobile Manufacturers 

released poll results finding that a majority (59 percent) of consumers “believe that technological 

innovations such as driver-assist technologies are making cars safer, and 6 in 10 consumers want 

to check out these systems next time they buy a car.”205

b) Security from new forms of cyber-attack

With increasing frequency, legislators and the media have raised questions about whether 

the prevalence of electronic control in today’s high-tech motor vehicles has created new vectors 

(or sources) for cyber-attack on the motoring public. For example, during a hearing in 2013, 

Senate Commerce Committee Chairman Jay Rockefeller asked, “As our cars become more 

connected -- to the Internet, to wireless networks, with each other, and with our infrastructure --

are they at risk of catastrophic cyber-attacks?”206 To date, NHTSA’s V2V research has not 

included research specific to this issue, as researchers assumed that the possibility of cyberattacks on motor vehicles was an existing vector of risk – not a new one created by V2V 

technologies. However, should the agency move forward with regulation, it may be important for 

improving public acceptance of the technology for us to assess, specifically, whether and how 

V2V technologies augment existing – or create additional – paths of cyber-attack that may affect 

motor vehicle security. The agency may also wish to explore the availability and appropriateness 

of measures to mitigate cyber-attack risks specific to V2V technologies (if any exist).

Additionally, efforts to achieve consumer acceptance through public outreach and education on 

the benefits of V2V technologies may help to assuage public concern that V2V technologies will 

increase the danger of cyber-attacks on motor vehicles.

In the June 5, 2013, poll released by the Alliance mentioned above, it was also found that 

consumers, when questioned about self-driving vehicles, expressed concerns about cybersecurity (i.e., 81 percent about a computer hacker controlling the car), companies collecting data 

from the self-driving cars (i.e., 75 percent), and companies sharing this information with the 

government (i.e., 70 percent). It is important to note that consumers were responding about self-

 

205 Consumers Still Want to Be in the Driver’s Seat, Self-Driving Cars Raise Concerns (Poll on Alliance Web site, 

June 5, 2013) at www.autoalliance.org/INDEX.CFM?OBJECTID=156688B0-CD5D-11E2-8898000C296BA163

(last accessed Jan. 29, 2014). 206 U.S. to monitor cybersecurity risks as car connectivity grows (Automotive News, May 15, 2013) at 

www.autonews.com/article/20130515/OEM11/305159928#axzz2Z1OdGToG (last accessed Jan. 29, 2014).
135

driving vehicles and not about V2V communication specifically,

207 but their concerns about 

cyber-security and collection of data about their driving behavior are concerns that consumers 

could have regarding any sort of vehicle for which they believed could present such risks.

While the agency recognizes the difference in potential risk between V2V technologies 

that simply warn drivers about impending danger and technologies that actually intervene in 

driving, this distinction may not yet be so clear to consumers, and work could be done to make 

that distinction clearer to improve public acceptability of V2V (ideally without also negatively 

impacting acceptability of more advanced technologies).

c) Reasonable cost increases

Another component of consumer acceptance is cost. The extent to which consumers are 

willing to embrace V2V technologies will depend, in part, on the resulting cost increase in new 

motor vehicles. Generally speaking, cost as an issue for consumers has been considered in terms 

of whether it is high enough to cause many consumers to delay purchasing a new vehicle. It is 

not an issue that has been raised very often – but, if consumers delay purchasing of new vehicles 

in any significant way, presumably there will be a delay in the stream of expected benefits. This 

is an issue that the agency considers for any safety regulatory action that it undertakes.

The preliminary costs for V2V (initial cost estimated at about $350 and then decreasing

with the learning curve) are less than some of the more notable safety equipment. For example, 

frontal air bags for the driver and right front passenger are estimated to cost $496, and antilock

brake systems are estimated to cost $424 (all in 2012 dollars).

d) Privacy protection and acceptable levels of risk to exposure

Perhaps the most significant component of consumer acceptance in the V2V context will 

be the extent to which V2V technologies create consumer anxiety about risks to individual 

privacy, whether the risks are actual or simply perceived. As discussed below, if consumers 

believe—contrary to the actual facts-- that the V2V system as contemplated will enable the 

government or others to track the speed or location of their motor vehicles, the public may be 

less likely to support a regulatory mandate requiring the technology, regardless of any resulting 

enhancements to levels of safety.

Should the agency move forward with a V2V regulation, it will need to perform and 

make public a privacy impact assessment (PIA) of its proposed V2V FMVSS. Discussed in 

detail in Section VII, a PIA must capture and quantify all privacy risks introduced by proposed 

regulatory requirements, and assess the extent to which technical, physical and organizational 

controls designed to minimize such risks do so adequately. Once complete, the PIA will enable 

 

207 See Section VII.A.3.b) for NHTSA’s current findings on driver responses to similar topics in the Safety Pilot.
136

NHTSA (and DOT as a whole) to determine whether the level of residual risk to individual 

privacy, with all controls in place, is acceptable. 

A critical part of any efforts to achieve consumer acceptance through public outreach 

will be assuring consumers that V2V technologies do not pose a significant threat to privacy and 

have been designed to help protect against vehicle tracking by the government or others.

Additional privacy research and analysis (some of which will be folded into the agency’s 

planned security and privacy risk assessments) is expected to provide NHTSA and DOT with an 

even more substantial basis for making such public assurances than currently exists.

2. Potential issues With industry support for V2V communication systems

Support from the automotive industry is not legally required in order for NHTSA to move 

forward with regulating V2V technology, but it is certainly desirable from a policy perspective, 

and may be important if the agency anticipates that the security system would be developed and 

stood up by an industry consortium. Industry support may be hindered by concerns about costs 

associated with the security system required to support V2V communications – who will bear the 

burden of such costs and, to the extent that it is the consumer, whether V2V can offer any “day 

one” benefits to consumers that justify the increase in new vehicle costs resulting from regulation 

of V2V technologies. Industry support also may be impaired both by uncertainty about how a 

regulatory action might impact in-vehicle crash avoidance systems, and by the perception by 

industry that V2V technologies will result in increased legal liability.

Additionally, for what appear to be largely economic reasons, industry support also will 

turn, in part, on the extent to which V2V technologies create consumer anxiety about actual or 

perceived risks to individual privacy. Industry members, through the VIIC and individually in 

meetings with NHTSA, have expressed concern that consumers will opt not to buy new vehicles 

if the agency mandates V2V technologies without protecting consumer privacy to the extent 

industry believes is necessary, and without providing consumers with assurances of privacy 

protection in a very public way, as through PSAs and public outreach.

Industry also may be able to use suggestions from the agency on how to facilitate 

consumer acceptance of V2V technologies if the agency eventually decides to require them. In 

addition to privacy, another factor that can be relevant to public acceptance of technologies is 

how well they work over the vehicle’s lifetime. As discussed elsewhere in this report, we 

anticipate that BSMs will need to be accompanied by security certificates to establish their 

trustworthiness; if vehicles need to be resupplied periodically with certificates, or if vehicles 

need software upgrades regularly (or even occasionally), there may be consumer acceptance 

issues if receiving these certificates and upgrades requires what they consider to be undue effort 

or expense on their part. At the same time, however, if consumers reject the effort or expense, 

the systems may not function properly, which can cause other consumer acceptance issues.

Ensuring appropriate consumer participation in V2V system maintenance will be a topic that the 

agency continues to explore.
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3. Preliminary information on consumer acceptance

As part of its research thus far, the agency has accumulated some preliminary information 

on consumer acceptance of advanced crash avoidance systems (sensor-based and V2V-based).208

This information provides an early look into consumer concerns and their perceptions on the 

value of these types of systems.

Based on our preliminary research described above, drivers generally have some interest 

in the new crash avoidance technologies, even if they do not yet have extensive knowledge about 

them. Consumers who have driven vehicles with crash avoidance technology appear to be 

generally positive about this technology, regardless of whether the technology is sensor-based or 

V2V-based. Exposure to specific crash avoidance technologies seems to increase drivers’ interest 

in purchasing those same technologies in future vehicles.

However, even though consumers express interest in purchasing vehicles with crash 

avoidance technologies, public opinion polls do not show that drivers are willing to spend a lot 

of additional money in order to purchase vehicles with these systems. In contrast, there is some 

indication that use of currently-available crash avoidance technologies has resulted in reduced 

claims/losses for the owners of vehicles with these features.209 If this trend continues and drivers 

determine that the new technologies can reduce their insurance costs, they might be willing to 

increase the amount of money they are willing to pay for a vehicle with crash avoidance 

technology.

The agency intends to supplement its preliminary research in the areas of consumer 

acceptance of V2V technology to better understand consumer behavior in reaction to these 

technologies. This research would help inform approaches for system implementation if the 

agency decides to move forward with a regulatory action.

 

208 Independent Evaluation of the Driver Acceptance of the Cooperative Intersection Collision Avoidance System 

for Violations (CICAS-V), Pilot Test July 2011, (Stearns and Garay-Vega, Report No. DOT HS 811 497) and

Integrated Vehicle-Based Safety Systems (IVBSS) Field Operational Test Final Program Report (Sayer, et al., June 

2011, Report No. DOT HS 811 482) both at 

www.nhtsa.gov/Research/Crash+Avoidance/Office+of+Crash+Avoidance+Research+Technical+Publications (last 

accessed Jan. 29, 2014).

209 More good news about crash avoidance, at 1-4 (Insurance Institute for Highway Safety, 2013, Status Report 48 

(3)) at www.iihs.org/externaldata/srdata/docs/sr4803.pdf (last accessed Jan. 29, 2014).
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Research Need VII-1 Consumer Acceptance210

Research Activity: Consumer Acceptance Research on V2V

Description: Supplement the driver acceptance analysis completed per the Driver 

Clinics and Safety Pilot Model Deployment with further research that 

includes a focused assessment of privacy in relation to V2V technology

Target Completion: 2015 (draft report to NHTSA)

Current or Planned NHTSA research addressing this need:

NHTSA will initiate Consumer Acceptance research in 2014.

a) Driver clinics conducted for connected vehicles and applications

As part of the V2V Light Vehicle Driver Acceptance Clinics project (conducted from 

September 2010 to March 2013), some preliminary assessments were made about whether and 

how drivers accept and respond to V2V safety technology. Beginning August 8, 2011, and 

ending January 21, 2012, four-day driver acceptance clinics were held in six cities,

211 with driver 

recruitment being conducted by independent recruitment agencies that used existing databases of 

known interested parties, advertisements, and/or cold-calling. At each clinic, around 112 drivers 

participated in a structured exposure to the V2V technology.

212 This exposure included 

completing pre-and post-drive questionnaires, receiving an oral and a video briefing about V2V 

technology, and being oriented to the vehicles and the course that would be driven. Clinic 

vehicles were supplied by nine OEMs, one from each OEM. Not all of the applications being 

assessed were included in each of the vehicles. In order for all of the participants to experience 

the majority of the safety features, some of the participants were asked to drive two different 

vehicles.213 In addition, 104 drivers at each clinic participated in a focus group discussion about 

the V2V technology and their experience in driving these vehicles.214

 

210 Intelligent Transportation Systems: Vehicle-to-Vehicle Technologies Expected to Offer Safety Benefits, but a 

Variety of Deployment Challenges Exist (Nov. 2013, GAO-14-13). See www.gao.gov/assets/660/658709.pdf (last

accessed Feb. 12, 2014).

211 Brooklyn, Michigan; Brainerd, Minnesota; Orlando, Florida; Blacksburg, Virginia; Fort Worth, Texas; and 

Alameda, California.

212 Specifically, the EEBL, FCW, BSW/LCW, DNPW, IMA, and LTA applications. 213 Participants driving the Ford, GM (Cadillac), Honda (Acura), or Mercedes were not asked to switch vehicles. 

Those driving the Toyota switched halfway to the Hyundai, and vice-versa, with similar switches being made 

between the Nissan (Infiniti) and the VW/Audi vehicles. 214 Vehicle-to-Vehicle Safety System and Vehicle Build for Safety Pilot [V2V-SP], Draft Final Report, Volume 1: 

Driver Acceptance Clinics (April 10, 2014). See Docket No. NHTSA-2014-0022.
139

Key findings from the pre- and post-questionnaires215 completed by drivers at these 

clinics include:

• Overall Impressions: Overall impressions of the V2V vehicles were positive, with 

approximately 85 percent of all responses considered to be positive. The most 

frequent negative response, accounting for only 4 percent of all responses, was a

general “disliked the warning.”

• Effectiveness: the majority of comments were positive regarding how effective the 

issued alerts were at communicating the direction of the scenario-specific threat (i.e., 

approximately 60 percent positive, with 22.5 percent giving a neutral response).

• Desirability: the desirability of the safety features was extremely high with 90 percent 

of participants agreeing that they would like to have the V2V communication safety 

feature in their personal vehicle.

• Intuitiveness: the intuitiveness of the vehicle’s alerts was rated very high (i.e., 

approximately 89 percent of respondents felt that the alert issued was extremely 

effective at gaining their attention and directing attention to the threat. Similarly, 90

percent agreed that the alert issued was easy to understand.).

• System Limitations: Most respondents (61.1 percent) were unsure whether or not 

drivers might confuse one warning with another from a different safety feature, while 

30 percent did not think this would be an issue.

• The majority of respondents (90.5 percent) would want to be notified whenever the 

V2V communication became unavailable; however, 43 percent of respondents stated 

that they would accept an unavailability rate of 10 percent or lower.

• The majority of respondents do not believe that the V2V benefit would be noticeable 

until 70-80 percent of vehicles are similarly equipped.

Some overall reactions by focus group members about V2V include:

• “Standard on all vehicles” was far preferred to the term “mandatory,” which some 

respondents perceived as too controlling. Participants felt that communication efforts 

 

215 Safety Pilot: Preliminary Analysis of the Driver Subjective Data for Integrated Light Vehicles (Scott Stevens, 

July 2013, HS63A3 – Project Memorandum). See Docket No. NHTSA-2014-0022
140

around the system should avoid the word “mandatory” or other terms implying 

government control, but could use terms such as “your own personal co-pilot.”

• Participants tended to agree that the benefits of saving lives and preventing or 

mitigating crashes far outweigh potential drawbacks such as driver dependency, 

complacency, and over-reliance on the system.

• Participants considered the scenarios experienced during the driving portion of the 

clinic as being very relevant and applicable to their everyday driving experiences.

• The applications considered the most appealing and/or relevant overall were FCW, 

BSW, EEBL, and IMA, although there was slight variation of this depending upon 

the region of the country that the respondent lived.

• Participants felt there were near-term problems (e.g., texting, disregard for rules, poor 

driving) that need to be addressed before starting a new, complicated, interdependent 

technology, even though there did not appear to be any short-term solutions in 

identified for these near-term problems.

• Participants’ reactions to the various warning implementations used by the OEMs 

(e.g., visual, audible, haptic where present and the locations thereof) were mixed, but 

there was a fair amount of consensus around having the warning appear the same 

across OEMs to avoid confusion when driving different vehicles.

b) Model Deployment driver acceptance surveys

As part of the Safety Pilot Model Deployment project, assessments were made to 

determine whether and how drivers accept and respond to V2V safety technology. The V2V 

technology with which these vehicles were equipped included six safety applications that were 

developed to assist the drivers in avoiding risky situations that might result in a crash if the 

driver did not take corrective action: EEBL, FCW, BSW/LCW, DNPW, IMA, and LTA,216

although not all of the applications being assessed were included in each of the vehicles.

During the first 6-month period (i.e., August 2012 to February 2013), half (i.e., 64) of the 

participants drove the vehicles, and, at the end of that 6-month period of time, filled out the 

driver acceptance survey. The remaining 64 drivers began driving the same OEM-provided and 

equipped vehicles at the beginning of the next 6 months of the pilot (i.e., February 2013), and 

 

216 See id., at 5, Table 1 for additional information on the safety features that were available by OEM. 
141

they filled out the same driver acceptance survey at the end of the next second 6-month period of 

time (i.e., August 2013).

A preliminary analysis was conducted on the subjective survey data obtained from the 

drivers who drove the V2V-equipped vehicles for the first 6 months, and was reported in a July 

2013 draft report. Overall, driver’s responses were very mixed toward the V2V safety features, 

with a large proportion of drivers giving neutral responses. Their responses to “What did you like 

most about the Connected Vehicle system?” included “Alerted me to traffic situations I 

otherwise wouldn’t have been aware of,” but the drivers focused on the rate of alerts that they

regarded as incorrect, with 42 percent citing incorrect alerts (e.g., distracting, not always clear, 

too short in duration), when asked what they like least.217 Especially in regard to FCW, the false 

alerts appeared to have some effect on desirability of the FCW safety feature. The more false 

FCW alerts a driver believed they had received, the less they agreed with the statement, “I would 

like to have FCW on my personal vehicle.”218

Since many of the driver survey questions that were used in the Driver Acceptance 

Clinics were used in the Safety Pilot Model Deployment, a comparison of results is possible.

However, the light vehicle Driver Acceptance Clinics were staged demonstrations of the V2V 

technologies that were conducted using integrated vehicles by each of the eight OEMs between 

August 2011 and January 2012. The volunteers drove equipped vehicles on a closed course 

through a series of staged scenarios designed to illustrate how the different safety features could 

be of use, and only interacted with other vehicles driven by professional drivers. The main 

difference was the overall distributions of answers to the questions asked, with almost all drivers 

giving the highest rating for every system and question for the Driver Acceptance Clinics,

whereas responses in the Safety Pilot Model Deployment were largely neutral. These results are 

not surprising given the differences in environment with the Driver Acceptance Clinics, a 

controlled demonstration, as compared to the Safety Pilot Model Deployment, a real-world 

driving situation. Table VII-1 and Figure VII-1 provide a sample of the distribution of driver 

responses.

 

217 Id., at 9. 218 Id., at 36.
142

Table VII-1 Comparison of Findings between Driver Acceptance Clinics and Safety Pilot 

Model Deployment during the First 6 Months

Driver Acceptance 

Clinics

Safety Pilot Model 

Deployment 

(Phase 1 Drivers)

Would like to have V2V 

technology on their personal 

vehicle

91% 30%

Most highly rated safety feature IMA BSW/LCW

Said distraction was less than 

using car radio

75% 51%

Thought the system would not 

cause overreliance

42% 73%

Amount young drivers worried 

about overreliance compared to 

older drivers

more Less

Main gender difference was Higher ratings for the 

EEBL by women (more 

useful, desirable, 

effective, and 

understandable)

Lower ratings for the 

IMA by women (less 

desirable, effective, 

understandable, and with 

more incorrect alerts)

Generally more favorable ratings for the overall system from older drivers in both, 

especially for the EEBL (higher ratings of FCW among older drivers only seen in Safety 

Pilot Model Deployment)

Figure VII-1 Full comparison of DAC and SP Driver responses

Upon completion of the Safety Pilot Model Deployment, the total data set, including the 

data from the second 6 months, will be analyzed to confirm the findings in this report. Since 

some changes were made to the safety applications that affected the false warning rates (i.e., 

decreased the number of false warnings), this analysis could prove to be very useful, in 

examining the rate and amount of change of a driver’s opinion about a V2V safety application as 

the false warning rate decreases. Information gained from this analysis can be used to judge 
143

future driver opinions of V2V safety applications, as the applications are improved, based upon 

the information obtained in the Safety Pilot Model Deployment.

Preliminary indications are that driver acceptance of the IMA application improved in the 

last 6 months of the project. This improvement in driver acceptance correlates with the enhanced 

performance of the IMA application as a result of changes by the OEMs to address the sources of

concern, especially what were perceived as false warnings. Generally, the applications used in 

the Model Deployment were not fine-tuned to suppress false warnings in situations where 

production systems would. Continued refinements, to the extent possible for IMA and other V2V 

applications, may help address some of the concern without affecting the effectiveness of the 

systems.

The survey also attempted to gauge participants’ concern with regard to privacy issues 

through four questions: “How willing would you be to have Connected Vehicle technology on 

your vehicle that, when combined with other information may allow:

A) A business entity to learn about your vehicle’s location and travel patterns?

B) The government to learn about your driving behavior and patterns?

C) A third party organization to learn about your driving behavior and patterns?

D) Appropriate personnel to determine criminal behavior such as hacking?

Note that these questions were intended to address possible perceptions, not the reality of 

the contemplated system, which is not designed to permit the collection of the types of data 

referred to in questions A through C.

In response, drivers did express concern about privacy with V2V technologies, with over 

half declaring that they were “not willing” to have businesses, government, or a third party 

organization learning about their driving behavior and patterns. When the idea of criminal 

behavior such as hacking was introduced, this number fell to 28 percent, indicating more people 

would be willing to accept some level of tracking. This is the clearest expression that the agency 

currently has of driver opinions of V2V privacy issues when drivers have actually experienced 

V2V technology over an extended period of time. While a larger sample set would be more 

informative, these results indicate that this is an issue that the agency needs to consider carefully 

as implementation proceeds.
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VIII. Privacy Considerations

A. Privacy considerations – what they are and why they are important

Risks to consumer privacy, whether actual or perceived, are intertwined with consumer 

and industry acceptance of V2V technologies. For this reason, privacy considerations are critical 

to the analysis underlying NHTSA’s decision about whether and, if so, how to proceed with V2V 

research or regulation.

At the outset, readers should understand some very important points about the V2V 

system as contemplated by NHTSA. The system will not collect or store any data on individuals 

or individual vehicles, nor will it enable the government to do so. There is no data in the safety 

messages exchanged by vehicles or collected by the V2V security system that could be used by 

law enforcement or private entities to personally identify a speeding or erratic driver. The 

system—operated by private entities—will not permit tracking through space or time of vehicles 

linked to specific owners or drivers or persons. Third parties attempting to use the system to 

track a vehicle would find it extremely difficult to do so, particularly in light of far simpler and 

cheaper means available for that purpose. The system will not collect financial information, 

personal communications, or other information linked to individuals. It will enroll V2V enabled 

vehicles automatically, without collecting any information identifying specific vehicles or 

owners. The system will not provide a “pipe” into the vehicle for extracting data. The system 

will enable NHTSA and motor vehicle manufacturers to find lots or production runs of 

potentially defective V2V equipment without use of VIN numbers or other information that 

could identify specific drivers or vehicles. 

Generally, privacy considerations inherent in mandated V2V technologies include such 

issues as:

• Should the V2V system provide “anonymity”219 for drivers, as suggested by industry, in 

order to prevent location tracking and otherwise protect individual privacy?

• Should the V2V system provide “anonymity” for drivers even if doing so:

o Prevents identification and prosecution of hackers accessing computers or data on 

the V2V system without authorization?

 

219 The VIIC has defined “real anonymity” as “end-to-end anonymity” (i.e., no collection of any personallyidentifying information at any time in connection with bootstrapping or provision of security services or mandatory 

applications). By contrast, NHTSA avoids use of the term “anonymity” in the V2V context, in recognition of the 

fact that some limited risks to individual privacy exist in the current V2V design even through it does not provide 

for collection of any individually identifying information. 
145

o Impedes NHTSA’s ability to investigate and recall defective V2V motor vehicle 

equipment (i.e., for highway safety purposes)?

• Or, for system security and/or highway safety purposes, should the V2V system collect 

data that may link location or other information that drivers may potentially perceive as 

sensitive (e.g., speed) to an individual driver or vehicle, either directly or indirectly?

• Are there ways to satisfy NHTSA’s need to identify potentially defective V2V devices 

without collecting data that may link location or other potentially sensitive information 

(e.g., speed) to an individual driver or vehicle, either directly or indirectly?

• Can a V2V system with no mechanism for identifying or tracking down hackers or other

“bad actors” be sufficiently secure for NHTSA or consumers to rely on?

• What specific risks to privacy stem from the V2V system? How likely is the potential 

occurrence of such risks? What would be the extent of harm if the events occurred? For 

example, to what extent do either the SCMS design or the unencrypted BSM introduce 

privacy risks, including but not limited to the risk of location tracking?

• What physical or technical controls should the V2V system contain to mitigate location 

tracking and other privacy risks “by design”?

• What policy or organizational controls should the V2V system contain in order to 

minimize the likelihood of unauthorized access to insider information that could facilitate 

tracking or create other risks to privacy?

• What role, if any, should or can the Federal Government play in assuring individual 

privacy in connection with mandated V2V technologies – especially if it plays no role in 

owning or governing the SCMS?

• Is Federal legislation necessary to protect consumer privacy adequately in the context of 

a mandated V2V FMVSS, as suggested by CAMP and the VIIC?

1. Transmission, collection, storage, and sharing of V2V data 

There are two primary categories of V2V system functions that involve the transmission,

collection, storage, and sharing of V2V data by, and between, the V2V system components and 

other entities: system safety and system security.

The V2V system’s safety functionality (i.e., the safety applications that produce crash 

warnings) requires that V2V devices in motor vehicles send and receive a basic safety message 

containing information about vehicle position, heading, speed, and other information relating to 

vehicle state and predicted path. The BSM, however, contains no personally identifying 

information (PII) and is broadcast in a very limited geographical range, typically less than 1 km.

Nearby motor vehicles will use that information to warn drivers of crash-imminent situations.

Except in the case of malfunction, the system will not collect and motor vehicles will not store 

the messages sent or received data sent/received by V2V devices.

The security needs of the V2V system require the exchange of certificates and other

communications between V2V devices and the entity or entities providing security for the V2V 
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system (i.e., the Security Certificate Management System). These two-way communications are 

encrypted and subject to additional security measures designed to prevent SCMS insiders and 

others from unauthorized access to information that might enable linkage of BSM data or 

security credentials to specific motor vehicles.

NHTSA also needs to ensure that the V2V system is protected from defective devices.

This agency safety function is likely to require that the V2V security system collect and share, on 

a very limited basis, some V2V data linking V2V device production lots to security credentials.

Neither the V2V system nor NHTSA will collect, store or have access to information that links 

production lots of defective V2V devices with specific VINs or owners.

2. Privacy policies framework

Industry members, via CAMP, the VIIC, and in individual OEM meetings with NHTSA, 

have suggested that the Federal Government should play a central role in protecting individual 

privacy in the V2V context, through regulation or governance over the SCMS. Both CAMP and 

the VIIC have taken the position that the security system for V2V technologies should conform 

to the central tenets of the VIIC Privacy Policies Framework (version 1.0.2), dated February 16, 

2007. That document would require that the security system:

• Collect and transmit only “anonymous” data from mobile users for mandatory 

applications

• Keep such data “anonymous” until securely destroyed

• Collect PII only with consent of the consumer

• Use/transmit that PII only in ways to prevent misuse/leakage and unauthorized attacks on 

the system

On the basis of these general tenets, the VIIC has identified as specific security system 

requirements:

• End-to-end anonymity for privately owned/leased vehicles and occupants for all 

mandatory V2V technologies, including security system processes (bootstrapping and 

certificate distribution) and mandatory applications and services

• For mandatory services, no ability to track specific identified vehicles across space and 

time, concurrent or after-the-fact

• Protection from attacks on system integrity, including from hackers and system 

administrators (i.e., “insiders”), by:

o Providing secure, end-to-end encryption of vulnerable communications;

o Changing short-term security certificates and vehicle identification every few 

minutes to prevent location tracking;

o Assigning certificate signing requests (CSRs) - now called Enrollment 

Certificates or Long-term Certificates -- in an anonymous fashion;
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o Providing for multiple, legally/administratively separate SCMS entities with 

distinct governances, none of which have sufficient knowledge, information, or 

means necessary to link short-term certificates to CSRs/Enrollment Certificates 

and ultimately to vehicles/OBE, all of which should be prohibited “by law” from 

allowing or colluding to achieve re-identification;

o Providing sufficient security to prevent hackers, users, and system administrators 

from accessing or deriving any information that can be linked, directly or 

indirectly, to individuals, motor vehicles, or OBE (e.g., via VIN or vehiclespecific part numbers).

CAMP and the VIIC also have taken the position that Federal legislation implementing 

the Privacy Policies Framework (as well as other policy and technical aspects of DSRC 

deployment) is necessary to provide adequate privacy protections for consumers in the context of 

mandated V2V technologies.

NHTSA takes privacy very seriously. If NHTSA moves forward with regulating V2V 

technologies, we are committed to doing so in a manner that both protects individual privacy and 

promotes this important safety technology. In NHTSA’s view, the VIIC’s 2007 Privacy Policies 

Framework provided an initial framework and useful starting point for development of privacyprotective V2V technologies. However, both V2V technologies and policies impacting privacy 

have continued to evolve over the last six years. Additionally, since 2007, DOT and V2V 

stakeholders have identified mission-critical and system-specific safety information needs that 

affect system privacy and have necessitated development of various additional controls to 

mitigate adverse privacy impacts. For these reasons, some aspects of the tenets and specific 

requirements set forth in that document no longer may be viable. 

For example, in order to preserve anonymity and prevent tracking, the 2007 Privacy 

Policies Framework envisioned the creation/collection of no data whatsoever that could link a 

security certificate that authenticates a V2V message to the on-board device or motor vehicle that 

generated that message. However, as discussed below, in order for NHTSA to investigate and 

ensure the recall of defective V2V equipment, the security system must collect/store data that 

facilitates linkage between some categories of misbehavior reports (to be identified as the 

misbehavior functions mature) and the production lots of V2V equipment that generated those 

messages. Without collection by the SCMS of such information, NHTSA will not have an 

adequate basis on which to ensure the system’s protection from defective devices.

As detailed below and elsewhere in this report, by design, V2V devices will transmit 

safety information in a very limited geographical range. Nearby V2V devices will use that 

information to warn drivers of crash-imminent situations. As currently designed, the system and 

V2V devices do not intend to collect or store the contents of messages sent or received.

However, in the case of malfunctions, a limited number of BSM elements relevant to assessing 

performance will be stored, but in a manner designed to preserve personal privacy to the
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maximum extent possible, consistent with the need to address the root cause of the malfunction if 

it is, or appears to be, widespread.

We have worked closely with CAMP and the VIIC to develop a technical and policy 

approach that helps guard against risks to individual privacy. As conceived, the system will 

contain multiple technical, physical, and organizational controls to minimize privacy risks –

including the likelihood of vehicle tracking by individuals and government or commercial 

entities. Additionally, even though V2V is still in a research phase, DOT’s Chief Privacy Officer 

and Office of the General Counsel and NHTSA’s Offices of the Chief Counsel and Chief 

Information Officer have worked closely with the DOT research team throughout the life of the

project to identify and assess the privacy implications of the V2V system and DOT’s related 

mission needs. For example, DOT’s Privacy Officer worked with the Office of the Chief Counsel 

of OST-R and the Office of the General Counsel to publish a Systems of Records Notice 

covering collection of personally identifying information during the Safety Pilot and, in so doing, 

identified appropriate controls to mitigate risks to individual privacy associated with that 

effort.220 These offices also supported the NHTSA’s V2V team in its initial assessment of the 

possible privacy risks associated with the V2V system (detailed below).

As aspects of the V2V system (such as the misbehavior functions, communications 

media, and ownership/governance models) become more defined, NHTSA will continue to work 

with the Department’s Privacy Officer and Office of the General Counsel to assess and reassess 

any threats to privacy that may be introduced by V2V technology and help identify mitigation 

measures to minimize any such risks. Additional discussion of NHTSA’s interim privacy risk 

assessment and next steps can be found in Section VIII.B.

3. The fair information practice principles

DOT and NHTSA privacy assessments are based on the framework of the fair 

information practice principles (FIPPs). Rooted in the tenets of the Privacy Act, the FIPPs 

provide a foundation for the privacy laws of multiple States, Federal and international 

governments, and organizations. A FIPPs-based analysis is predicated on privacy control 

families articulated in the Federal Enterprise Architecture Security and Privacy Profile (FEASPP) v3, sponsored by the National Institute of Standards and Technology (NIST), the Office of 

Management and Budget (OMB), and the Federal Chief Information Officers Council, and the 

Privacy Controls, articulated in Appendix J of the NIST Special Publication 800-53 Security and 

Privacy Controls for Federal Information Systems and Organizations.

 

220 77 Fed. Reg. 12641 (Mar. 1, 2012) at www.gpo.gov/fdsys/pkg/FR-2012-03-01/pdf/2012-4964.pdf (last accessed Jan. 

30, 2014).
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The control families consist of:

• Transparency: What mechanisms will provide the consumers with information about the 

data being collected and transmitted by the V2V system and how that data will be used?

• Individual Participation and Redress: Will consumers have a reasonable opportunity to 

make informed decisions about the collection, use, and disclosure of their PII, if 

collected, or other data that may be used to identify them, directly or indirectly? Will they

be active participants in decisions regarding the collection and use of their data?

• Purpose Specification: For what purposes is the system collecting, using, maintaining, 

or disseminating the specific data elements or categories of data being collected? (for 

example, here is where NHTSA might indicate that V2V data collected by roadside 

infrastructure will be aggregated, de-identified, and transmitted for use in mobility, 

environmental, and/or commercial applications)

• Data Minimization: Explain why the data collection isn’t excessive and how long the 

data will be retained

• Use Limitation: Assure the subjects of the data collection that the data will not be used 

for purposes incompatible with the purpose for which it was collected (as detailed in the 

purpose specification section)

• Data Quality and Integrity: How will the system assure data quality and integrity 

throughout the data lifecycle and in all business processes associated with data use?

• Security: What physical, technical and procedural measures will system administrators 

take to protect the data? The PIA’s analysis of security controls in the security system 

that mitigate privacy risks should be specific enough to provide consumers with a 

comprehensive understanding and adequate assurance that information is protected – but 

not provide a roadmap for would-be hackers to attack the system.

• Accountability and Auditing: How does system ensure that the privacy controls 

outlined above are executed?

The answers to these questions and the specific controls that NHTSA will need to 

identify and require, if consistent with our legal authority, within each of the control families,

will flow from a technical privacy risk analysis of the V2V system. This analysis will be 

conducted once now-fluid aspects of the security system design (e.g., misbehavior management) 

are closer to finalization, once the agency knows how the SCMS will be managed (e.g., owned,

organized, and operated), and once the agency knows what communications media will be 

selected by the SCMS owners for messaging between the SCMS and V2V devices.
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A draft Privacy Impact Assessment (PIA), based on the agency’s technical risk analysis,

would need to be completed and ready for publication concurrent with any NPRM that NHTSA 

may issue, should it move forward with regulatory action. A PIA is an analysis required by the 

E-Government Act of how the V2V system handles information in identifiable form221 to:

• Ensure compliance with applicable legal, regulatory, and policy requirements 

regarding privacy;

• Determine the risks and effects of collecting, maintaining, and disseminating such 

information in an electronic information system; and,

• Examine and evaluate protections and alternative processes for handling 

information to mitigate potential privacy risks.222

The draft and final PIA will document how DOT has considered and analyzed privacy 

from the beginning stages of the V2V system’s development throughout the system’s life cycle 

(i.e., collection, use, retention, processing, disclosure, and destruction). The PIA also gives the 

public notice of this analysis and helps promote trust between the public and the Department by 

increasing transparency of the Department’s systems and missions.

In order to conduct this comprehensive privacy risk assessment of the V2V system as part 

of a V2V regulatory action, NHTSA will need to identify and quantify the level of any privacy 

risks stemming from each of the three discrete areas of the V2V system -- the OBE/DSRC 

messages, the communications media for messaging between the SCMS and V2V devices, and 

the SCMS. Although a PIA cannot be finalized until a draft NPRM exists, most of the technical 

analysis can be completed well in advance of that time. The next section describes NHTSA’s 

work on a PIA to date.

B. NHTSA’s interim privacy risk assessment

NHTSA, with the support of the DOT Privacy Officer and NHTSA’s Office of the Chief 

Information Officer, conducted an interim privacy risk assessment of the V2V system. As 

multiple aspects of the system design remain in flux, the initial privacy risk assessment was 

 

221 The E-Government Act of 2002 applies to “information in identifiable form.” The National Institute of Standards 

and Technology (NIST) has stated that the term “information in identifiable form” is “[o]ften considered to have 

been replaced by the term PII [personally identifiable information].” See Guide to Protecting the Confidentiality of

Personally Identifiable Information (PII), Appendix C (April 2010, NIST Special Publication 800-122) at 

www.nist.gov/manuscript-publication-search.cfm?pub_id=904990 (last accessed Jan. 29, 2014). However, NIST 

also notes that terms such as “information in identifiable form” are similar to NIST’s definition of PII and 

“organizations should not use the term PII (as defined in this report) interchangeably with these terms and 

definitions because they are specific to the ir particular context.” Id. 222 OMB Guidance for Implementing the Privacy Provisions of the E-Government Act of 2002 (Sept. 26, 2003, 

OMB Memorandum, M-03-22, Attachment A, Section II.A.6) at www.whitehouse.gov/omb/memoranda_m03-22

(last accessed Jan. 29, 2014).
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based on a “snapshot” of the V2V system envisioned by the CAMP/DOT research team. In 

addition, this assessment assumed that SCMS would have one important additional capability 

(not a part of the prototype security system design) required to address NHTSA’s need for 

information to support its defect investigation and recall duties.

The initial privacy risk assessment contains an important caveat, namely, that further 

development of the technology or organization of the V2V system is likely to result in changes –

possibly significant changes -- to the interim privacy analysis and findings. For this reason, the 

interim assessment was intended to provide the structure and serve only as a robust starting point 

for NHTSA’s definitive assessment of risks to privacy that could stem from a V2V regulatory 

action. As the V2V system and NHTSA’s procedural posture evolve, so too will the scope of and 

detail in this privacy assessment.

The primary system components analyzed were:

1. The OBE and BSM – On-Board Equipment (OBE) as well as BSMs containing 

unencrypted GPS/location data required for V2V safety applications;

2. The Communications Network – use of DSRC, cellular, or other communications 

media to transmit encrypted security-related messages between OBEs (and possibly 

RSEs) and the SCMS; and

3. The SCMS – the organizations/functions/infrastructure providing PKI security to the 

V2V system.

Our interim analysis assumed that any V2V system deployed through a NHTSA 

regulatory action will have a capability not inherent in the latest SCMS design: the ability for 

DOT and/or the V2V equipment manufacturers to access information that links problematic 

certificates/messages collected by the SCMS with production runs or lots of potentially defective 

V2V equipment. This capability would have ensured that information NHTSA needs for defect 

and compliance purposes is collected by OEMs and/or relevant SCMS entities and made 

available to the agency in a timely manner.

As is the case with all such analyses, NHTSA’s interim risk assessment included the 

following procedural steps:

• Establish Business Needs: What are the critical business needs that a V2V system 

must satisfy?

• Identify System Functions: What system functions serve those business needs?

• Identify Data Needs/Transactions: What data needs/transactions stem from the 

identified system functions?

• Describe Nature of Resulting Risks: What risks result from the collection, storage, 

or dissemination of data on the system? Do the data transactions increase privacy 

risks to existing related systems (both safety and security systems within a motor 
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vehicle, and opt-in systems like OnStar that collect motor vehicle data from on-board 

systems and transmit it elsewhere)?

• Identify and Explore Technical/Policy Controls: As currently envisioned, what 

technical and policy controls mitigate the identified privacy risks? Should there be 

others?

• Determine Likelihood: What is the likelihood of the risks? Likelihood is calculated 

for threat, vulnerability, and impact as part of the risk impetus (i.e., an individual or 

organization’s motive for engaging in the activities creating the risk), not the risk 

itself. This can be expressed as, L = [(T * V)/I]. This inquiry necessarily must take 

into account the relative cost and ease of access to the same data via existing 

technologies and data sources.

• Quantify Resulting Risks: On the basis of consequence/harm and likelihood, what is 

the impact of the resulting risks, can those risks be mitigated by any controls, and are 

there risks that remain unmitigated (i.e., residual risk)? Residual risk comes from the 

application of controls to the risk set RR = R – I.

• Assess Consequences/Harm: What are the consequences of the potential risks 

identified?

It is important to emphasize that residual risk stemming from the V2V system will never 

be zero due the inherent complexity of the V2V system design and the diversity/large number of 

interacting components/entities, both technological and human. Additionally, technology 

changes at a rapid pace and may adversely impact system controls designed to help protect 

privacy in unforeseen ways. For these reasons, as is standard practice in both the public and 

private sectors, the primary function of a privacy risk assessment is to identify residual risk and 

its potential consequence/harm. On the basis of that critical information, agency decision-makers 

then will be in an informed position to determine whether that residual risk is acceptable – and, 

in the alternative, whether functionality should be sacrificed in order to achieve an acceptable 

level of residual risk, and if so, what functionality.

On the basis of then available information and stated assumptions, NHTSA’s interim risk 

assessment identified the system’s business needs, relevant system functions, nature of the 

resulting risks, and existing/other technical and policy controls. It also captured the team’s 

attempt to provide an initial rough estimate of the extent, likelihood, and consequences/harm of 

risk stemming from the system. There was consensus among the team members that, should 

NHTSA proceed with regulatory action, DOT will need to obtain technical input from external 

security and privacy experts by proceeding with planned privacy research. Such research will 

help us to make a more fine-grained estimation of the extent, likelihood, and consequences/harm 

of risk stemming from the V2V system. It also will assist the Department and NHTSA in 

garnering public support for V2V by providing technical data to support NHTSA’s position that 

the V2V system protects the privacy of participants and makes geo-locational tracking highly 

unlikely.
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It is important also to note that NHTSA’s interim privacy assessment did not take into 

account the business or informational needs of other DOT modal administrations, other Federal 

agencies (such as DOJ, DHS, FCC, and FTC), and State and local stakeholders. NHTSA will 

need to consider whether to expand our assessment to identify and analyze the different or 

additional privacy risks that may stem from the V2V-related activities and needs of other

entities. For example, the safety, mobility, and environmental V2I and V2X applications being 

developed primarily by FHWA, FMCSA, and their respective stakeholders might generate 

different or additional information needs. The FTC, as the entity that regulates the privacy 

relationships between private entities and consumers, may have some interests in the privacy 

practices and controls (including information collection) designed into V2V security system if 

the system ends up being owned and managed privately. Finally, the FCC, as regulators of the 

spectrum, might have informational needs related to their enforcement functions, the collection 

of which could impact our privacy risk assessment.

1. V2V system needs/functions that necessitate data transactions posing potential 

risks to privacy

NHTSA’s interim privacy analysis identified three categories of V2V system 

needs/functions that pose potential risks to privacy during data transactions:

• System safety (BSM data sent/received by V2V devices to enable safety 

applications)

• System security (certificates and other communications between V2V devices and 

SCMS)

• Agency safety and enforcement functions (data linking V2V device production 

lots to long-term enrollment certificates)

The critical foundation for NHTSA’s privacy risk assessment is the data collected, 

transmitted, stored and disclosed within, by, and between the V2V system components and other

entities. The team identified several data needs/transactions that could introduce privacy risks 

into the V2V system, including:

• The collection, transmittal, storage, and potential uses of unencrypted GPS and 

related path history information used in safety applications;

• The collection of data linking long-term security credentials with production 

runs/lots of V2V equipment used by NHTSA in investigation and recall purposes;

• The certificate and related linkage/bundling data collected and transmitted within 

the various functions of the SCMS used for distributing certificates; and

• The transmission and storage of location information broadcast when cellular (a 

potential communication option) is used as a method of communication between 

V2V devices and the SCMS for security-related purposes used for distributing 

certificates and other security-related communications.
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2. Potential risks to privacy introduced by V2V communications or other data 

transactions necessary to satisfy system need

The team identified the following potential risks to privacy in the V2V system on the 

basis of the V2V data transactions that are necessary to satisfy system needs: (a) location 

tracking via BSM; and (2) identification of individuals and individual behaviors.

a) Location tracking via BSM

NHTSA is aware of concerns that the V2V system could broadcast or store BSM data 

(such as GPS or path history) that, if captured by a third party, might facilitate very-localized 

vehicle tracking. In fact, the broadcast of unencrypted GPS, path history, and other data 

characteristics in or derived from the BSM appears to introduce only very limited potential risks

to individual privacy. Preliminary research performed for NHTSA suggests that tracking a

specific car or driver based on BSM would be both difficult and costly. Nevertheless, the 

likelihood of tracking – or availability of information and technologies that facilitate linking 

location or other BSM data to a specific motor vehicle, address, or person – will be a key inquiry 

for DOT/NHTSA and their privacy and security consultants going forward.

Research Need VIII-1 V2V Location Tracking via BSM

Research Activity: Privacy Risk Assessment of V2V System

Description: Assess the availability of information and technologies that facilitate 

linking data in the BSM to determine a motor vehicle’s path

Target Completion: 2015 (draft report to NHTSA)

Current or Planned NHTSA research addressing this need:

NHTSA will conduct a privacy risk assessment of the V2V system that includes an analysis of 

the ability of vehicles to be tracked via BSM transmissions and the resultant impact of possible 

tracking to an individual’s privacy

It is theoretically possible that a third party could try to capture the transitory locational 

data in order to track a specific vehicle. However, we do not see a scenario in which one wishing 

to track a vehicle would choose the V2V system as the means. Nevertheless, NHTSA is 

conducting further research to accurately assess the level of privacy risk inherent in the broadcast 

of unencrypted BSM data.

Other methods exist for tracking a vehicle’s location path, such as through electronic 

emanations from the car itself or from on-board electronics such as cell phones (although DOT 

consultants advise that both methods are expensive and difficult) and use of a single identifier 

broadcast from the vehicle (e.g., E-ZPass, OnStarTM). NHTSA’s planned comprehensive privacy 

risk assessment will need to consider the ease and cost of other methods of location tracking in 

connection with assessing the likelihood of location tracking via data in the unencrypted BSM.
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b) Identification of individuals and individual behaviors:

Because a BSM does not identify a specific vehicle or individual, the V2V system as 

currently designed would not provide such a clear link to a driver or owner. However, the ease 

with which BSM data characteristics may be used to identify, either directly or indirectly, a 

specific vehicle, driver, or owner will be a subject of ongoing research and will be central to 

NHTSA’s assessment of the likelihood of various risks to privacy.

Research Need VIII-2 V2V Identification Capabilities

Research Activity: Technical Analysis of the Potential Privacy Risk of V2V Systems

Description: Understanding and quantifying risk of linking vehicle tracking or other

information in the BSM to a specific vehicle, address, or individual via 

available resources (including but not limited to database matching or data 

mining) 

Target Completion: 2015 (draft report to NHTSA)

Current or Planned NHTSA research addressing this need:

NHTSA will conduct a privacy risk analysis of the V2V system that includes an investigation of 

the use of BSM records to identify a vehicle, address, or individual.

At the component level, the specific potential tracking risks include:

• OBE/BSM: Location tracking via radio identification

• Network Communications: Location tracking via cellular IP address or computerspecific Wi-Fi address

• SCMS: Location tracking via after-the-fact reconstruction of GPS info in linked 

security certificates

3. Technical, physical and/or policy controls evaluated to minimize potential

privacy risks

Generally, privacy risk controls fall into 3 categories:

• Physical Controls: Physical protections that reduce privacy risks (for example, a 

tamper-proof casing around the computer module storing a motor vehicle’s 

certificates or high-security access procedures to gain physical access to an SCMS 

server facility)

• Technical Controls: Data-protective technologies designed into a system

• Policy Controls: Laws or organizational policies that make unauthorized data 

collection, storage, or disclosure less likely by creating organizational and/or 

functional separation and imposing organizational or legal consequences against

hackers or malfeasant insiders
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The current V2V security design contemplates a PKI security system that makes use of 

both asymmetric and symmetric keys and other technical, organizational, and policy controls 

(including, as applicable, compliance with the Privacy Act, FISMA223 and other Federal statutes, 

regulations and policy relevant to privacy in Federal information technology systems) intended 

to prevent or make far more difficult tracking of devices, either contemporaneously or after the 

fact. Examples of technical controls in the current security design intended to minimize the risk 

of tracking via linking of security credential information in the unencrypted BSM include 5 

minute certificates and shuffling of certificates prior to reuse.

The SCMS design also anticipates policy controls like organizational and/or functional 

separation, and organizational consequences to deter collusion that might enable tracking, such 

as separation of the enrollment function from the certificate issuance/distribution functions; 

separation of the certificate issuance and distribution functions; and having several certificate 

shuffling and location-obscuring functions.

As discussed above in connection with governance, ultimately, the SCMS Manager will 

be the entity that establishes and enforces physical, policy, and technical controls that are 

applicable to: (1) all of the CME entities that make up the SCMS, and (2) the communications 

media used by CME organizations to communicate with both V2V devices and RSE. Once 

greater clarity of the SCMS structure and governance emerges, we will need to inventory and 

assess the privacy controls applicable to the SCMS in connection with our comprehensive 

privacy risk assessment.

Research Need VIII-3 V2V Inventory of Privacy Controls

Research Activity: Technical Analysis of the Potential Privacy Risks of V2V Systems

Description: Inventory and assess the privacy controls applicable to the SCMS in 

connection with our comprehensive privacy assessment

Target Completion: 2015 (draft report to NHTSA)

Current or Planned NHTSA research addressing this need:

NHTSA will conduct a privacy risk analysis of the V2V system (Research Need VIII-4) that 

includes the development of an inventory and assessment of privacy controls. 

4. Significance of the identified potential privacy risks

Assessing the significance of the potential risks to privacy that stem from the V2V 

system, in light of identified controls to mitigate those risks, is the final step in a comprehensive 

privacy analysis. With the help of subject-matter experts, NHTSA will need to quantify the level 

 

223 Federal Information Security Management Act of 2002.
157

of each potential privacy risk. The level of privacy risk (typically categorized as high, medium, 

and low) is a function of:

a) Adverse impacts to privacy that would arise if the circumstance or event occurs; 

and

b) Likelihood of Occurrence (which necessarily must take into account the relative 

cost and ease of access to the same data via existing technologies and data 

sources).

Thus, Privacy Risk = Impact x Likelihood.

Overall, based on present information and our interim privacy assessment, we have 

reason to believe that a properly-designed V2V system would curtail any serious risks to privacy. 

The agency acknowledges there may be no way to entirely eliminate privacy risks from the V2V 

system, but believes the efforts expended to develop robust security system designs to protect 

individual privacy collaboratively through our cooperative research efforts appear to meet that 

need. However, NHTSA intends to perform an even more comprehensive and definitive 

assessment of any proposed regulatory action to identify potential risks to privacy and ensure 

that appropriate controls are in place to help mitigate such risks.

Research Need VIII-4 V2V Privacy Risk Assessment224

Research Activity: Technical Analysis of the Potential Privacy Risk of V2V Systems

Description: A comprehensive privacy risk analysis of all aspects of the V2V system 

including infrastructure equipment, on-board vehicle systems, wireless 

and wired communications, as well as organizational and management 

issues. This assessment will include previously identified Research Needs 

in this section: V2V Location Tracking via BSM; VIII-2, V2V 

Identification Capabilities; and VIII-3, V2V Inventory of Privacy Controls

Target Completion: 2015 (draft report to NHTSA)

Current or Planned NHTSA research addressing this need:

This privacy risk analysis will provide the information about the latest security design and 

related privacy risk to enable the Department to perform a comprehensive Privacy Impact 

Assessment as required by law to determine how to balance individual privacy, data security, and 

safety.

 

224 Intelligent Transportation Systems: Vehicle-to-Vehicle Technologies Expected to Offer Safety Benefits, but a 

Variety of Deployment Challenges Exist (Nov. 2013, GAO-14-13). See www.gao.gov/assets/660/658709.pdf (last 

accessed Feb. 12, 2014).
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IX. V2V Communications Security

A. Overview and importance of security

Public acceptance and the adoption of cooperative V2V safety applications will depend 

on appropriate levels of security as an integral part of the system. In contrast to other types of 

safety technologies, the V2V safety applications are cooperative—meaning that both vehicles 

must send, receive, and analyze data in real-time. This cooperative exchange of data about 

potential threats and hazards forms the basis of alerts and warnings to drivers to support their 

decisions and actions to avert impending incidents. This is a new paradigm that is in contrast to 

the stand-alone sensor-based vehicle system. However, a cooperative system can only work 

when participants in the system are able to trust the alerts and warnings issued by V2V devices

working with messages from other V2V devices.

Thus, the basis of a relevant V2V security system is “trust”—a requirement that 

thousands of data messages will be authenticated, in real-time, as coming from a trusted (if 

unknown) source. It is also a critical element in achieving interoperability—o that vehicles of 

different make/model/year will be able to exchange trusted data without pre-existing agreements 

or altering the actual vehicle designs.

Further, the system must be secure against internal and external threats or attacks. Three 

primary elements of the V2V system require security:

1. Communications (the medium, the messages/data, the certificates, and any other

element that supports message exchange);

2. Devices; and

3. Structure (organizational, operational, and physical).

Last, in addition to these requirements, the system needs to be: scalable to meet the needs 

of over 350 million users across the Nation; extendable to accommodate other types of 

applications such as V2I mobility, management, and environmental applications; and financially 

sustainable.

Eleven years of research (i.e., examination of different security approaches, technical 

architecture and configuration decisions, testing of prototypes, and development of an 

operational and organizational structure) have resulted in the current security design concept for 

a V2V system, as discussed below.

Cryptography is the approach that has been used historically to secure communications.

Intended recipients have a “key” that allows them to decrypt and read the original message. It 

can be implemented in varying ways to achieve different levels of security. These include: (a) 

data confidentiality; (b) data integrity; (c) authentication; (d) non-repudiation (which means a 
159

sender cannot deny a message that they have sent); or (e) authorization (grants access rights to 

others to perform actions).225

Encryption techniques rely upon algorithms that have evolved significantly over time and 

were recently accelerated by the advent of powerful computers. Algorithms are calculations with 

well-defined steps that can be followed as a procedure—in this case, a procedure to encrypt and 

decrypt information.

The operations are dependent upon a separate piece of information known as a “key” 

which can be varied and which then varies the output of the algorithm. In a “symmetric” 

encryption system, there is one key—the secret key used to encrypt the message is the same one 

used to decrypt a message. In an asymmetric encryption system, keys come in pairs—each 

message sent contains one half of this key pair, and the receiving device has the other key.

Advancements in computing power provide industry with the ability to employ advanced 

algorithms and larger keys, thus making decryption thousands of times more difficult without the 

key.

1. Security options considered

In considering which option would most effectively provide trusted message exchange 

and secure communications for safety-critical applications, the DOT and V2V research 

development team (including CAMP security experts) compared three options—symmetric 

encryption systems, group signature systems, and asymmetric public key infrastructure systems. 

When assessing these alternatives, the V2V research team (both DOT and CAMP members) was 

looking for an option that:

• Did not require the identity of the participating parties and, accordingly, supported the 

goal of appropriately preserving privacy;

• Was fast enough to fit within the bandwidth constraints of DSRC and the processing 

constraints of the V2V on-board equipment;

• Entailed a number of over-the-air bytes needed for security that fit within the constraints 

of DSRC bandwidth and size of the BSM in the message payload; and

• Supported non-repudiation.

 

225 Handbook of Applied Cryptography (Menezes, van Oorschot, and Vanstone, ISBN 0-8493-8523-7) at

http://cacr.uwaterloo.ca/hac/about/chap1.pdf (last accessed June 28, 2013).
160

Table IX-1 provides a comparison of the “options” as alternatives and notes that

characteristics of each approach are beneficial to the V2V needs or contain “fatal flaws.” The (*) 

denotes characteristics that do not meet key criteria for the V2V system (safety, security, 

privacy, latency, cost, non-repudiation are the key criteria) while the (^^) denotes beneficial 

characteristics.

Table IX-1 Security Approach Alternatives226,227

1. Symmetric Key Systems

This approach requires that both parties have the same secret key. Securely distributing keys in such a 

system becomes infeasible when securing multiple types of devices with a large and expanding base of 

users. The approach is suitable for systems where the endpoints can be tightly controlled – for example, 

tolling, or ATMs, or military radio. Asymmetric cryptography is suitable for systems where membership 

is highly dynamic or where endpoints cannot be so tightly controlled – for example, web browsers or 

postage stamps.

Cryptography 

method Beneficial Characteristics Limitations

Symmetric-key 

ciphers

(stream 

ciphers, block 

ciphers)*

 Extremely fast

Key distribution or pre-storage is:

 A security vulnerability and

 Too cumbersome at large scale*

 There is no non-repudiation.

o Global symmetric-key is more 

vulnerable to compromise.

o V2V needs authentication for trust, 

not encryption (BSM not encrypted).

Arbitrary 

length hash 

 Fast, could be used if anchored by 

periodic certificates

 Need for key distribution in later packets 

adds over-the -air overhead and slows 

 

226 Cryptographic primitives are well-established, low-level cryptographic algorithms that are frequently used to 

build computer security systems. These routines include, but are not limited to, one-way hash functions and 

encryption functions. When creating cryptographic systems, designers use cryptographic primitives as the ir most 

basic building blocks. Because of this, cryptographic primitives are designed to do one very specific task in a highly 

reliable fashion. They include encryption schemes, hash functions and digital signatures schemes. Since 

cryptographic primitives are used as building blocks, they must be very reliable, i.e., perform according to the ir 

specification. Id. 227 E.g., Understanding PKI: concepts, standards, and deployment considerations, at 11-15 (Adams & Lloyd, 2003) 

at Docket No. NHTSA-2014-0022; Managing information systems security and privacy, at 69 (Trček, 2006) at

Docket No. NHTSA-2014-0022; Public key infrastructure: building trusted applications and Web services, at 8

(Vacca, 2004) at Docket No. NHTSA-2014-0022; and Network Security with OpenSSL, at 61-62 (Viega, et al., 

2002) at Docket No. NHTSA-2014-0022.
161

functions 

(MACs)228, 

(“keyed hash”)

latency

 May require precise timing regime (e.g., 

TESLA) 

Pseudorandom 

sequences

• Building block for 

authentication/encryption 

• Cannot be used on their own for 

authentication or encryption 

Identification 

primitives*  Extremely fast

 Same key distribution issues as symmetrickey ciphers*

 Risk to privacy*

2. Public Key Infrastructure Systems (Asymmetric Key Systems)

Organizations today predominantly use PKI as a primary means of securing communications. This 

approach allows users to “...securely communicate on an insecure public network, and reliably verify 

the identity of a user via digital signatures.” The system also allows for the “...creation, storage, and 

distribution of digital certificates which are used to verify that a particular public key belongs to a 

certain entity. A PKI system creates and manages digital certificates, which maps public keys to entities 

or permissions, securely stores these certificates in a central repository; distributes them to users as 

needed (or upon request); and revokes them in the case of misuse, system or devices failures, or 

malicious behavior.” The public key(s) in an entity’s certificate can be used to authenticate the entity, 

directly encrypt data for the entity, or establish a shared symmetric key that can be used to protect bulk 

data.

Cryptography 

method Beneficial Characteristics Limitations

Public-key 

ciphers

 Easy distribution of public key

 Can distribute pairwise or group 

symmetric keys for bulk 

encryption

V2V needs authentication for trust, not 

encryption (BSM not encrypted).

Signatures

 Easy distribution of public key^^

 May gain sufficient speed coupled 

with appropriate certificate 

exchange mechanism (e.g., Verify 

on Demand or Periodic broadcast)

 Slower than symmetric systems

 Adds more packet overhead than 

symmetric systems

Identification 

primitives  Building block for signatures  In general interactive – cannot be used to authenticate broadcast messages.

3. Group Signatures (Subset of PKI Systems)

This approach allows a single public key to verify signatures created by the many unique private keys of 

all the group members. The keys are issued by a central authority that can identify misbehavers and 

revoke credentials. Only group members have a valid signature and a member of a group can 

anonymously sign a message on behalf of the group. The signer is anonymous, except the signer can be 

identified with the group manager’s secret key; thus, the anonymity can be broken by the group manager.

 

228 The acronym MAC has two accepted industry definitions depending on the industry and context. For this context 

it is defined as Message Authentication Code.
162

Cryptography 

method Beneficial Characteristics Limitations

Group 

Signatures

 Easier key distribution - Single 

public key verifies many unique 

private key

 Anonymous except to the central 

authority

 Signature too big for over-the -air 

requirements*

 Revocation checking is computationally 

expensive

 Lose backwards privacy protection at 

revocation*

 Master key holder can forge messages and 

compromise privacy

4. Non-Keyed Systems

These are simply algorithms that are useful building blocks in other cryptographic systems. Note that 

with the evolution of cryptographic technologies over the years, non-keyed options are no longer 

considered separate alternatives, but building blocks used to implement either the Symmetric-key or 

Public-key options. Thus, the first two options are the only actual alternatives to choose from (group 

signatures were dismissed because of the privacy requirements).

Cryptography 

method Beneficial Characteristics Limitations

Arbitrary 

length hash 

functions

Used as building block in keyed 

methods (e.g., signatures)

Not keyed, so can’t be used on their own to

establish identity or to encrypt data*

One way 

permutations

Used as building block for signatures Not keyed, so can’t be used on their own to 

establish identity or to encrypt data*

Random 

sequences

Used as building block in keyed 

methods (e.g., group linkage values). 

Allow efficient construction of 

sequences for which an adversary 

cannot guess the next or previous 

entry

Not keyed, so can’t be used on their own to 

establish identity or to encrypt data*

Arbitrary 

length hash 

functions

Used as building block in keyed 

methods (e.g., signatures)

Not keyed, so can’t be used on their own to 

establish identity or to encrypt data*

In viewing the tables above, the public key infrastructure option (asymmetric key) using 

the signature method was deemed to offer the most effective approach to implementing 

communications security and trusted messaging for a very large set of users. Thus, it was chosen 

for the BSM. Importantly, the effectiveness of this approach is highly dependent upon the 

technical design decisions regarding how to implement this approach in its given environment.
163

2. Overview of PKI and how it works

How a PKI architecture is implemented can vary from one system to another. The 

choices made in configuring a PKI architecture speak to the type of goals and objectives for a 

system and focus on choices that:

• Support a particular level of strength of security or privacy that is desired or needed by 

the system, and assure longevity to the security that is longer than the lifespan of the 

equipped vehicles.

• Support scalability; extensibility to other uses (if desired); system operations, 

maintenance, upgrades, and evolution needs; and ease of access and use requirements

• Address issues such as technology limitations or constraints, or cost limitations

• Mitigate risks and types of attacks envisioned on the system.

Noting the system objectives articulated by the research team (trusted messaging, feasible 

operations, and appropriate privacy protection), the following discusses the basic elements of any 

PKI, and notes the challenge in designing a security approach specific to the V2V system.

All basic PKI systems are comprised of the following elements and functions, at a 

minimum229

• A Certificate Authority (CA)—an entity that acts as the “trusted third party” to 

provide the action to “authenticate” the entities within a network. It typically does so 

by signing and distributing digital certificates. The CA also typically revokes 

certificates and publishes a certificate revocation list so that valid users know to 

ignore certificates of users who have been revoked. A CA is considered the root of 

trust in a PKI.

• A Registration Authority (RA) — the entity that is certified to register users and 

issue certificates. This function is performed by the CA in the simplest PKI systems.

• A Root Certificate Authority (sometimes the CA and sometimes a separate 

entity)—the highest trusted entity within a PKI security system, the Root CA 

typically has a self-signed and issued certificate. A certificate that is issued by a 

CA to itself is referred to as a trusted root certificate, because it is intended to 

establish a point of ultimate trust for a CA hierarchy. Once the trusted root has 

 

229 E.g., http://msdn.microsoft.com/en-us/library/windows/desktop/bb427432(v=vs.85).aspx (last accessed Jan. 30, 

2014); https://www.juniper.net/techpubs/en_US/junos10.4/information-products/topic-collections/nce/pki-conftrouble/index.html?topic-49285.html (last accessed Jan. 30, 2014) and

www.google.com/url?sa=t&rct=j&q=&esrc=s&frm=1&source=web&cd=8&cad=rja&ved=0CFAQFjAH&url=http

%3A%2F%2Facs.lbl.gov%2F~mrt%2Ftalks%2FsecPrimer.ppt&ei=ua7IUdyTBvKv4APlqYCABg&usg=AFQjCNH

O-XXndSLpKwls7VHbNsk_Ckmamw&sig2=d5L8IFMnEegw39L1dE-hJA (last accessed Jan. 30, 2014).
164

been established, it can be used to authorize subordinate CAs to issue certificates 

on its behalf.230

• Digital Certificates (also known as public key certificates)—electronic 

“documents” that use a digital signature to bind a public key with an identity.

231

Digital certificates are verified using a chain of trust. The trust anchor for the 

digital certificate is the Root CA. Many software applications assume these root 

certificates are trustworthy on the user's behalf. For example, a web browser uses 

them to verify identities within SSL and TLS secure connections. However, this 

implies that the user trusts their browser's publisher, the certificate authorities it 

trusts, and any intermediates the certificate authority may have issued a 

certificate-issuing-certificate, to faithfully verify the identity and intentions of all 

parties that own the certificates. This (transitive) trust in a root certificate is the 

usual case. The most common commercial variety is based on the International 

Telecommunication Union Telecommunication Standardization Sector standard 

X.509.232

• Secure hardware and software (servers, stores, repositories; also known as a central 

directory)—hardware and software to support the processing of certificate requests, 

save issued certificates before they are distributed, or save revoked certificates. May 

generate certificates and validate received certificates. Also used in back-up systems.

• Communications—wire line, wireless, or Internet services that provide the 

communications capacity over which management capabilities are enacted to receive 

requests, distribute certificates, collect misbehavior reports, revoke certificates, and 

distribute the CRL. Average sizes of PKI objects are:

• Private/public key pair = typically 1 KB

• Local certificate = 2 KB

• CA certificate = 2 KB

• CA authority configuration = 500 bytes

• CRL (average size is variable, depending on how many certificates have been 

revoked by a particular CA) = typically between 300 bytes to 2MB+

Basic technologies used in achieving security levels with these PKI elements include the 

following.

233

• Encryption provides confidentiality; can provide authentication and integrity protection

• Hash algorithms/checksums provide integrity protection; can provide authentication

• Digital signatures provide authentication, integrity protection, and non-repudiation.

 

230 See http://technet.microsoft.com/en-us/library/cc778623(v=ws.10).aspx (last accessed Feb. 25, 2014). 231 See www.verisign.com.au/repository/tutorial/digital/intro1.shtml (last accessed Jan. 30, 2014). 232 See www.itu.int/rec/T-REC-X.509 (last accessed Jan. 30, 2014). 233 An Introduction to Distributed Security Concepts and Public Key Infrastructure (PKI) (Mary Thompson) See

www.google.com/url?sa=t&rct=j&q=&esrc=s&frm=1&source=web&cd=8&cad=rja&ved=0CFAQFjAH&url=http

%3A%2F%2Facs.lbl.gov%2F~mrt%2Ftalks%2FsecPrimer.ppt&ei=ua7IUdyTBvKv4APlqYCABg&usg=AFQjCNH

O-XXndSLpKwls7VHbNsk_Ckmamw&sig2=d5L8IFMnEegw39L1dE-hJA (last accessed Jan. 30, 2014).
165

All of these approaches are employed in the V2V security design concept, as well as 

some unique technologies such as butterfly keys and linkage values that will be defined in the 

next section.

3. Limitations of existing PKI systems

No other PKI system exists today that is broad enough to serve as a key safety-critical 

model. Most other systems involve data exchange among parties that are either known to each 

other as trusted sources (e.g., the military knows each of its communication points) or are 

identifiable (e.g., the FAA air traffic controllers around the Nation can identify each of the planes 

involved in safety-critical data exchange). Also, most other safety-critical systems employ highly 

secure networks (e.g., the military) or private networks (e.g., the military) and cannot leverage 

either existing communications systems or the Internet (to keep capital investment costs to a 

minimum and to achieve widespread access) in a manner that does not introduce additional 

vulnerabilities and risks.

Most of the existing commercial systems, by comparison, do leverage the Internet and 

wireless systems. These systems enable on-line purchasing or on-line financial transactions in a 

way that allows for easy accessibility to millions of users. They do not, however, meet the level 

of privacy protection, as these organizations have pre-existing agreements with the CA and thus 

user identity resides within databases and is typically used as part of the authentication process.

B. Current V2V security design concept

Figure IX-1 presents, at a high level, the basic use-cases of the V2V security system. 

They are similar to the basic functions of any PKI.
166

Figure IX-1 Simplified V2V Security System

SCMS Manager

Certificate 

Processing

Device Interface

Device

Misbehavior 

Detection and 

Revocation

The remainder of this section expands upon this basic design to present the current V2V 

security design. Figure IX-2 illustrates the complexity of the V2V security design associated 

with meeting V2V environment needs. After the illustration, each component is defined.
167

Figure IX-2 Current V2V Security System Design for Deployment and Operations

This image presents both an initial deployment model as well as a full deployment model.

Note that this diagram shows the initial deployment model where there is no Intermediate CA 

and the Root CA talks to the MA, PCA, and ECA (dotted lines). In the full deployment model, 

these entities communicate with the Intermediate CA instead of the Root CA to protect the Root 

CA from unnecessary exposure (solid line).
168

Additionally, it should be noted that in initial deployment, some entities are considered 

centralized-by-choice for simplicity and because multiple entities are not required while the 

number of equipped vehicles is small. As penetration increases, these entities can proliferate and 

become decentralized. The entities that are expected to only have one in initial deployment 

include the Root CA, the Enrollment CA, the LOP, CRL Store, and CRL Broadcast.

This more complicated technical design is current as of January 2014. The technical 

design was provided by:

• The Crash Avoidance Metrics Partnership, a team of eight OEMs and their security 

experts and other partners.234 This team developed the illustration.

• The VIIC—a consortium of OEM policy staff supporting the technical design team.

The technical design has been reviewed for its technical functionality by staff of the DOT

from NHTSA, the ITS JPO, FHWA, and the Volpe Center.

1. SCMS component functions

The following discussion of SCMS functions focuses on communications and activities 

within the SCMS. The technical design for the SCMS includes several different operating 

functions that together make up the overall SCMS structure.

We note that the interactions between the components shown in Figure IX-2 are all based 

on machine-to-machine performance. No human judgment is involved in creation, granting, or 

revocation of the digital certificates. The functions are performed automatically by processors in 

the various V2V components, including the OBE in the vehicle. The role of personnel within the 

SCMS is to manage the overall system; protect and maintain the computer hardware and 

facilities; update software and hardware; and address unanticipated issues.

Generally, these SCMS operating functions fall into two categories: pseudonym functions 

and bootstrap functions. In order for the SCMS to support the security needs of the V2V system, 

the various SCMS functions must work together to exchange information securely and 

efficiently.

2. Pseudonym functions/certificates

The security design makes use of short-term digital certificates used by a vehicle’s onboard equipment to authenticate and validate sent and received basic safety messages that form 

the foundation for V2V safety technologies. These short-term certificates contain no information 

about users to protect privacy, but serve as credentials that permit users to participate in the V2V

 

234 Including security experts from ESCRYPT, Inc., CAMP, and Booz Allen Hamilton.
169

system. Pseudonym functions create, manage, distribute, monitor and revoke short-term 

certificates for vehicles. They include:

• Intermediate Certificate Authority (Intermediate CA) is an extension of the Root CA 

shielding it from direct access to the Internet. It can authorize other Certificate 

Management Entities (CMEs) (or possibly an Enrollment Certificate Authority [ECA]) 

using authority from the Root CA, but does not hold the same authority as the Root CA in 

that it cannot self-sign a certificate. The Intermediate CA provides flexibility in the 

system because it obviates the need for the highly protected Root CA to establish contact 

with every SCMS entity as they are added to the system over time. Additionally, the use 

of Intermediate CAs lessens the impact of an attack by maintaining protection of the Root 

CA.

• Linkage Authority (LA) is the entity that generates linkage values. The LA has been 

designed to come in pairs of two, which we refer to as LA1 and LA2. The LAs for most 

operations communicate only with the RA and provide values, known as linkage values, 

in response to a request by the RA (see below) and PCA (see below). The linkage values 

provide the PCA with a means to calculate a certificate ID and a mechanism to connect 

all short-term certificates from a specific device for ease of revocation in the event of 

misbehavior.

• Location Obscurer Proxy (LOP) obscures the location of OBE seeking to communicate 

with the SCMS functions, so that the functions are not aware of the geographic location 

of a specific vehicle. All communications from the OBE to the SCMS components must 

pass through the LOP. Additionally, the LOP may shuffle misbehavior reports that are 

sent by OBEs to the MA (see below) during full deployment. This function increases 

participant privacy but does not increase or reduce security.

• Misbehavior Authority (MA) acts as the central function to process misbehavior reports 

and produce and publish the certificate revocation list. It works with the PCA, RA, and 

LAs to acquire necessary information about a certificate to create entries to the CRL 

through the CRL Generator. The MA eventually may perform global misbehavior 

detection, involving investigations or other processes to identify levels of misbehavior in 

the system. The MA is not an external law enforcement function, but rather an internal 

SCMS function intended to detect when messages are not plausible or when there is 

potential malfunction or malfeasance within the system. The extent to which the CMEs 

share externally information generated by the MA about devices sending inaccurate or 

false messages – either with individuals whose credentials the system has revoked or with 

law enforcement – will depend on law, organizational policy, and/or contractual 

obligations applicable to the CMEs and their component functions.

• Pseudonym Certificate Authority (PCA) issues the short-term certificates used to ensure 

trust in the system. In earlier designs their lifetime was fixed at five minutes. The validity 

period of certificates is still on the order of “minutes” but is now a variable length of 

time, making them less predictable and thus harder to track. Certificates are the security 

credentials that authenticate messages from a device. In addition to certificate issuance, 
170

the PCA collaborates with the MA, RA, and LAs to identify linkage values to place on 

the CRL if misbehavior has been detected.

• Registration Authority (RA) performs the necessary key expansions before the PCA 

performs the final key expansion functions. It receives certificate requests from the OBE 

(by way of the LOP), requests and receives linkage values from the LAs, and sends 

certificate requests to the PCA. It shuffles requests from multiple OBEs to prevent the 

PCA from correlating certificate IDs with users. It also acts as the final conduit to 

batching short-term certificates for distribution to the OBE. Lastly, it creates and 

maintains a blacklist of enrollment certificates so it will know to reject certificate renewal 

requests from revoked OBEs.

• Request Coordination is critical in preventing an OBE from receiving multiple batches of 

certificates from different RAs. The Request Coordination function coordinates activities 

with the RAs to ensure that certificate requests during a given time period are responded 

to appropriately and without duplication. Note that this function is only necessary if there

is more than one RA in the SCMS. The technical process behind this function is still 

under development.

• Root Certificate Authority (Root CA)) is the master root for all other CAs; it is the 

“center of trust” of the system. It issues certificates to subordinate CAs in a hierarchical 

fashion, providing their authentication within the system so all other users and functions 

know they can be trusted. The Root CA produces a self-signed certificate (verifying its 

own trustworthiness) using out-of-band communications. This enables trust that can be 

verified between ad hoc or disparate devices because they share a common trust point. It 

is likely that the Root CA will operate in a separate, offline environment because 

compromise of this function is a catastrophic event for the security system.

• SCMS Manager is the function that will provide the policy and technical standards for the 

entire connected vehicle industry. Just as any large-scale industry ensures consistency 

and standardization of technical specifications, standard operating procedures, and other

industry-wide practices such as auditing, the SCMS Manager would perform and monitor 

these types of activities. This can happen in a number of ways. Often in commercial 

industries, volunteer industry consortiums take on this role. In other industries, or in 

public or quasi-public industries, this role may be assumed by a regulatory or other legal 

or policy body. Despite the choice of how to implement a central administrative body, it 

is expected practice that one would be established for the SCMS. As no decisions about 

ownership or operation have been made, we do not advocate for public or private 

ownership, but include the basic functions we expect the SCMS Manager would perform 

in our discussions and analyses. The expectation is that the SOPs, audit standards, and 

other practices set by this body would then be executed and complied with by each CME 

individually. It is also assumed that any guidance, practices, SOPs, auditing standards, or 

additional industry-wide procedures would be set based on any Federal guidance or 

regulation. The SCMS will also remove or revoke entities that do not comply with 

standards or misbehave.
171

3. Initialization functions/enrollment certificate

The security design also includes functions that carry out the bootstrapping process, 

which establishes the initial connection between a motor vehicle’s OBE and the SCMS. The 

chief functional component of this process is the Enrollment Certificate Authority that assigns a 

long-term enrollment certificate to each OBE. To the extent required by NHTSA or other

stakeholders, it is during the bootstrap process that the SCMS can create a link between specific 

OBEs or production lots of OBEs and enrollment certificates that later may be used by OEMs 

and NHTSA to identify defective V2V equipment. The design does not indicate when 

bootstrapping should take place, but NHTSA has suggested that it might need to take place at the 

time of OBE manufacture to facilitate the level of linkage between long-term enrollment 

certificates and equipment production lots that NHTSA needs for enforcement purposes (e.g., to 

identify defective equipment).

Note that, at this time, bootstrap functions have been fairly well defined for OBEs. The 

process for establishing the connection between aftermarket safety devices and the SCMS has 

not been defined; nor will it be defined by CAMP (it will need to be defined by ASD 

manufacturers who will need to work with the final structure of the SCMS to determine how to 

do this process).

Initialization functions include:

• Certification Lab does not take part in the particular use cases [of the SCMS]. It instructs 

the ECA on polices and rules for issuing enrollment certificates. This is usually done 

when a new device is released to the market or if the SCMS Manager releases new rules 

and guidelines. The Enrollment CA uses information from the Certification lab to 

confirm that devices of the given type are entitled to an enrollment certificate. As 

identified in Section VI.G, details regarding the Certification and Enforcement are not 

currently determined.235

• Device Configuration Manager (DCM) is responsible for giving devices access to new 

trust information, such as updates to the certificates of one or more authorities, and 

relaying policy decisions or technical guidelines issued by the SCMS Manager. It also 

sends software updates to the OBEs. The DCM coordinates initial trust distribution with 

OBE by passing on credentials for other SCMS entities, and provides the OBE with 

information it needs to request short term certificates from an RA. The DCM also plays a 

 

235 At this point, the extent and level of testing that the Certification Lab will actually perform is still to be 

determined. The role of the labs could range from simply managing a checklist of requirements to performing 

extensive technical certification tests, including: device performance, FCC compliance, cryptographic testing (at the 

level of FIPS-140), and/or interoperability testing. The intent is that the SCMS manager, after it is created, will 

determine the full roles and responsibilities of the Certification Lab. Vehicle and device manufacturers may decide 

to rely in part on a certification lab to support the ir own certification of compliance with any relevant standards 

NHTSA may issue.
172

role in the bootstrap process by ensuring that a device is cleared to receive its enrollment 

certificate from the ECA. It also provides a secure channel to the ECA. There are two 

types of connections used from devices to the DCM: in-band and out-of-band 

communications. In-band communication uses the LOP, while out-of-band 

communication is sent directly from the OBE to the ECA by way of the DCM.

• Enrollment Certificate Authority (ECA) verifies the validity of the device type with the 

Certification Lab. Once verified, the ECA then produces the enrollment certificate and 

sends it to the OBE. Once the OBE has a valid enrollment certificate, it is able to request 

and receive certificates from the SCMS.

a) Unique technologies employed in the current V2V PKI security system design

Following are some of the additional technologies that are unique to the V2V PKI 

Security System:

b) Butterfly Keys:236

Butterfly keys are a novel cryptographic construction that allows a device to request an 

arbitrary number of certificates, each with different signing keys and each encrypted with a 

different encryption key, using a request that contains only one verification public key seed and 

one encryption public key seed and two “expansion functions” (which allows the second party to 

calculate an arbitrarily long sequence of statistically uncorrelated (as far as an outside observer is 

concerned) public keys such that only the original device knows the corresponding private keys).

Without butterfly keys, the device would have to send a unique verification key and a 

unique encryption key for each certificate. Thus, butterfly keys reduce the upload size of 

certificate requests, and allow requests to be made when there is only spotty connectivity 

(although they also increase the size of the certificate upload). They also reduce the work to be 

done by the requester to calculate the keys, thus reducing computational burden.

(1) Linkage values

To support efficient revocation, end-entity certificates contain a linkage value that is 

derived from cryptographic seed material. Publication of the seed is sufficient to revoke all 

certificates belonging to the revoked device, but without the seed an eavesdropper cannot tell 

which certificates belong to a particular device. (Note: the revocation process is designed such 

that it does not give up backward privacy.) For protection against insider attacks, the seed is the 

combination of two seed values produced by two Linkage Authorities; this ensures that no single 

organizational entity knows enough information to identify a single device. An extension to the 

linkage values approach allows for group revocation, so that if all devices of a particular type 

 

236 A Security Credential Management System for V2V Communications (Whyte, Weimerskirch, Kumar, and 

Hehn). See Docket No. NHTSA-2014-0022=
173

have a flaw they can be revoked with a single entry on the revocation list, while keeping group 

membership secret until the relevant group seed is revealed. Group revocation is considered an 

option besides revocation of single devices.

Linkage values and linkage authorities (LAs) are used to enable the SCMS to support 

seven requirements.

• There should be an efficient way of revoking all the certificates within a device

• There should be an efficient way of revoking all the certificates within a group of 

devices

• Certificates should not be linkable by an eavesdropper unless the owner has been 

revoked

• Membership to a group should not be disclosed unless that group has been revoked

• If a vehicle’s security credentials are revoked, the vehicle should be identifiable going 

forward but its movements before it was revoked should not be trackable.237

• Similarly, if a group of vehicles’ security credentials are revoked, a device belonging 

to that group should be identifiable as a member. However, it should not be possible 

to determine the membership to a group before the group revocation took place.

• No single entity within the system should be able to determine that two certificates 

belong to the same device or to the same group. An exception to this rule is the 

Misbehavior Authority.

If there is a requirement that no single entity within the SCMS should be able to identify

a vehicle, once an LA is introduced, this requirement is no longer fulfilled. For that reason, two 

LAs are introduced and the information that allows for identification is split between them.

(2) Misbehavior Authority/CRL

Most SCMS functions listed above are fairly well developed. One critical function, which 

has not yet been fleshed out adequately for DOT to assess, is the Misbehavior Authority (MA) --

the central function responsible for processing misbehavior reports generated by OBE and 

producing and publishing the CRL. This list, once distributed, identifies digital certificates that 

are no longer valid and the OBE should no longer rely on messages from the identified digital 

certificates. The size of the CRL depends on the frequency of list distribution and rate of 

misbehavior across the vehicle fleet. On-board storage for and the costs of distributing the CRL 

are two major cost generators in the technical design.

The MA also will be responsible for performing global misbehavior detection, involving 

the collection of a sampling of misbehavior reports from OBE for purposes of detecting systemwide misbehavior and revoking misbehaving entities. Global detection processes have not yet 

 

237 Because the current design now reuses certificates, vehicles will be backwards-trackable for the period of the 

batch life. This design anticipates certificate batches to be valid for a week.
174

been defined. Should NHTSA decide to move forward with regulatory action, it will be 

important for NHTSA to continue to work with CAMP and perhaps other consultants to mature 

the misbehavior detection processes,238 as these are critical to system integrity and have a direct 

relationship to system costs.

Research Need IX-1 Misbehavior Authority239

Research Activity: Misbehavior Detection

Description: Development of the processes, algorithms, reporting requirements, and 

data requirements for both local and global detection functions; and 

procedures to populate and distribute the CRL.

Target Completion: Initial requirements completed in 2015 (draft report to NHTSA) 

Current or Planned NHTSA research addressing this need:

NHTSA is currently working with CAMP to develop Misbehavior Detection and Reporting 

strategies for both local and global misbehavior detection. Initial requirements that define the 

Misbehavior Authority functions will be complete in 2015. Validation and demonstration efforts 

will continue through 2016.

4. Comparing a basic PKI to the V2V security design

Based on the definition of these additional elements that is needed for a secure V2V 

environment, Figure IX-3 illustrates the differences between a “basic PKI system” that is similar 

to those in use today versus the V2V PKI that can deliver the highest levels of privacy 

protection, can be scaled to support 350M+ users, and can mitigate risks and attacks that are 

associated with systems in use today and in the near future.

 

238 Some specific tasks could include evaluating: (1) how onboard diagnostics for V2V devices for local detection 

(malfunction) could reduce the size of the CRL; (2) how misbehavior search algorithms for global detection 

(malfunction and malicious) could be developed; (3) the approach and feasibility of using “epidemic distribution” to 

eliminate the need for a CRL; and (4) what new vulnerabilities to attack and what new enhanced data 

communication capability exist. 239 Intelligent Transportation Systems: Vehicle-to-Vehicle Technologies Expected to Offer Safety Benefits, but a 

Variety of Deployment Challenges Exist (Nov. 2013, GAO-14-13). See www.gao.gov/assets/660/658709.pdf (last 

accessed Feb. 12, 2014).
175

Figure IX-3 V2V Security Design Comparison to a Basic PKI

The boxes in blue are the entities/functions found in every PKI. The boxes in gold are 

typically associated with today’s PKI systems. The boxes in light green are unique to the V2V 
176

PKI. Note that the complexity requires an overall “security credentials management system” 

manager. Note also that some entities/functions are split to support privacy preservation.

The additional elements added by the research team to the V2V security design are 

needed for the following reasons:

• The requirement to protect privacy appropriately requires a system that divides and 

separates some of the functionality to ensure that no one element (entity) has the 

ability to match records that would lead to identification of a specific driver or 

specific vehicle.

• There are two linkage authorities that create linkage values. Linkage values allow one 

entry on the CRL to revoke an entire batch of certificates, instead of having to list 

each certificate. This drastically reduces the size of the CRL and the communications 

requirement. An LA has enough information that an inside attacker can track a user. 

Therefore, the linkage value comes from the output of two separate linkage 

authorities, neither of which has enough information to track anyone. Splitting the 

linkage authority creates additional privacy protection but also increases 

organizational costs.

• The need for appropriate privacy protection has led to a greater amount of digital 

certificate usage; digital certificates use random identifiers that change frequently so 

as to lower the risk of identifying any one vehicle or driver with a particular digital 

certificate. The decision on how many certificates are used in a given time period or 

how to employ random identifiers is still to be determined (options are described but 

not yet decided upon). It may be a flexible choice based on type of application.

Notably, allowing for different schemes might also make attacks on the system more 

difficult.

• Privacy considerations also have resulted in the addition of an element to obscure 

location coordinates when a vehicle or device communicates with the system (e.g., to

request more digital certificates or to report misbehavior detected locally, around the 

vehicle).

• While misbehavior authorities exist in today’s PKI system (typically as a part of a 

CA) to detect and take actions to mitigate or remove malicious behavior, the V2V 

PKI’s MA is described as a separate and more complex entity than exists today. Not 

all of the described functionality of the V2V MA has been demonstrated (e.g., the use 

of local detection and reporting) in industry. It is, however, planned for demonstration 

and testing as an operational prototype that is being planned as part of the ongoing 

near-term CAMP research.

• The trust requirement has resulted in the design of a direct interface with a 

certification lab entity to verify that each type of device meet standards proving their 

capabilities to be trusted, secure, and interoperable.

• Request coordination is added as a function to ensure that an OBE cannot obtain 

multiple batches of certificates by sending requests to several RAs at the same time.
177

5. V2V security research conducted or underway

Table IX-2 provides a summary of the security research conducted over the past eleven 

years and currently underway. The research supported the development of a SCMS, explained 

previously, that was prototyped for the Safety Pilot Model Deployment. The different research 

projects built off of the previous research projects to investigate and then define the components 

and processes of a security system for V2V communications. The prototype SCMS that was 

implemented to provide Safety Pilot Model Deployment communications security will provide 

data that will be used to understand and evaluate the capabilities of the current prototype, and 

possibly indicate how it can be improved.

Table IX-2 V2V Communication Security Research

Research Project Time Period Research Focus

Vehicle Safety 

Communications 

(VSC)

2002-2005 Secure communications that included identifying 

options for:

• Trust mechanisms

• ID misbehaving devices

• PKI architecture 

Review by the National 

Institute of Standards 

and Technology 

(NIST)

2004 NIST reviewed the security options alternatives 

analysis, agreed with the security approach chosen 

(PKI), reviewed the emerging PKI configuration for 

V2V, and identified concerns that the research team 

would need to address as development moved 

forward.

Vehicle Safety 

Communications –

Applications (VSC-A)

2006-2010 Development of high-level security design that 

covered:

• Over-the-air performance of an authentication 

scheme

• Identification of privacy mechanisms

• Analysis of channel options for security

• Refinement of the attacker model

• Initial development of misbehavior detection 

schemes
178

Research Project Time Period Research Focus

Vehicle-to-VehicleCommunications 

Security (V2V-CS)

2010-2012 Research Objectives included:

• Determined security requirements and derived 

communication channel requirements.

• Delivered a simplified initial and final deployment 

security model that identified the 3000/year 

certificate model with no infrastructure required 

for the first three years.

• Performed a system-based risk assessment using 

the proposed initial and full deployment models.

Assessment identified both privacy and security 

risks.

• Began definition of the SCMS to understand the 

organizational and operational requirements; 

identified a need to research ownership/operations 

from a centralized versus non-centralized 

perspective.

• This version of the SCMS formed the basis for the 

Safety Pilot Model Deployment prototype.

Vehicle-to-VehicleInteroperability, Phase 

1 (V2V-I)

2010-2012 Research objectives for defining interoperability 

included further research into security from an 

operational perspective. The research covered:

• Definition of a concept of operations for a V2V 

security; tested the operations with 200 vehicles 

to observe channel congestion using both 

cellular and DSRC.

• Definition of a process of certificate 

management and an initial process for 

misbehavior detection.

• Publication of design specifications on IP.com 

and licensing of the operational design for use 

in the Safety Pilot Model Deployment.

Oak Ridge National 

Laboratories (ONRL)

2012 Before the launch of the Safety Pilot Model 

Deployment, ORNL tested the prototype security 

system.
179

Research Project Time Period Research Focus

Safety Pilot Model 

Deployment (SPMD)

2012-2013 Implementation of a prototype that included:

• Support for device initialization

• Pre-load of certificates onto devices

• Over-the-air certificate reload

• Testing of the certificate revocation list

• Testing of misbehavior reporting function

Vehicle-to-VehicleVehicle Safety 

Communications 

Security Studies (V2VVSCS)

2012-2014 Research is underway and includes:

• Finalization of the SCMS design with a focus on 

simplifying and optimizing operations

• Cost analysis of the SCMS with a sensitivity 

analysis on the assumptions associated with the 

current design concept.

• Identification of optional methods to link batches 

of on-board equipment devices to enrollment 

certificates

V2V Interoperability 

Project/Phase 2 (V2VI/Phase 2)

2012-2014 Research is underway and is focused on misbehavior 

detection and reporting – the algorithms and 

operational requirements needed to ensure that this 

function works under real-world conditions that will 

lead to development of a deployment use case.

Independent 

Evaluation of V2V 

Security System Design

2014-2015 To better understand the state of the current design, 

the DOT needs an independent entity’s assessment to 

inform the DOT of the status of the design and 

provide a basis for future policy and technical 

decisions.

6. Overall application of cryptography in V2V communications

The security approach for V2V system is based predominantly on use of a public key 

infrastructure to support trusted messaging, feasible operations, and appropriate privacy 

protection. Other forms of security—symmetric encryption, physical security and system 

controls, organizational security, and legal deterrence policies are incorporated judiciously 

throughout the system. The decisions on where and how to apply security have been made with 

safety as the highest priority, and a balance between protecting privacy appropriately, latency 

and bandwidth concerns, preliminary costs, flexibility, and non-repudiation. Additionally, all of 
180

the cryptographic methods are expected to provide a security level of at least 128 bits and are 

NIST compliant.

240

Below is a high level but technical summary of how these various mechanisms are built 

and applied at key risk points throughout the system:

• Digital Certificates: Are based on the Elliptic Curve Qu-Vanstone Implicit 

Certificate Scheme241; and IEEE Standard 1609.2-2013242 is used for generating 

digital certificates. Keys with the certificates are generated using the “butterfly keys” 

scheme, which is not yet standardized.

• Digital Signatures: Are based on the Elliptic Curve Digital Signature Algorithm 

from the Digital Signature Standard that is used for digitally signing messages.243

Note that NIST requires the use of a hash function (SHA-256244) during ECDSA 

signature generation, for security purposes. The CAMP design follows this principle.

• Asymmetric Encryption: Elliptic Curve Integrated Encryption Scheme as specified 

in IEEE Standard 1363a-2004245 is used for asymmetric encryption. In the CAMP 

design, ECIES is used only to encrypt a symmetric key, which is then used for 

encrypting a message to the receiver using symmetric encryption (as described 

below). ECIES internally makes use of keyed-hash message authentication codes.246

 

240 Approved Security Functions for FIPS 140-2 (May 30, 2012, Federal Information Processing Standard 

Publication, Annex A) at http://csrc.nist.gov/publications/fips/fips140-2/fips1402annexa.pdf (last accessed Jan. 30, 

2014); and Recommendation for Pair-Wise Key Establishment Schemes using Discrete Logarithm Cryptography, 

Revised (Mar. 2007, NIST Special Publication 800-56A) at http://csrc.nist.gov/groups/ST/toolkit/documents/SP800-

56Arev1_3-8-07.pdf (last accessed Jan. 30, 2014). 241 As specified in the Certicom Research, see:

• Standard for Efficient Cryptography (SEC) 4: Elliptic Curve Cryptography, version 2.0., (Certicom 

Research, May 21, 2009) at www.secg.org/download/aid-780/sec1-v2.pdf (last accessed Jan. 30, 2014). 

• SEC 4: Elliptic Curve Qu-Vanstone Implicit Certificate Scheme (ECQV), version 1.0. (Certicom Research, 

Jan. 24, 2013) at www.secg.org/download/aid-796/sec4-1.0.pdf (last accessed Jan. 30, 2014). 242 Wireless Access in Vehicular Environments: Security Services for Applications and Management Messages

(IEEE Std. 1609.2-2013) at 

http://ieeexplore.ieee.org/xpl/articleDetails.jsp?tp=&arnumber=6509896&queryText%3D1609.2 (last accessed Jan. 

30, 2014).

243 Digital Signature Standards (DSS) (NIST, FIPS PUB 186-4, Jul. 2013) at 

http://nvlpubs.nist.gov/nistpubs/FIPS/NIST.FIPS.186-4.pdf (last accessed Jan. 30, 2014). 244 Secure Hash Standard (SHS) (Mar. 2012, NIST, FIPS 180-4,) at http://csrc.nist.gov/publications/fips/fips180-

4/fips-180-4.pdf (last accessed Jan. 30, 2014). For a description of SHA-256, see

http://csrc.nist.gov/groups/STM/cavp/documents/shs/sha256-384-512.pdf (last accessed Jan. 29, 2014). 245 Standard Specification for Public-Key Cryptography-Amendment 1: Additional Techniques (IEEE Std. 1363a2004,) at 

http://ieeexplore.ieee.org/xpl/articleDetails.jsp?tp=&arnumber=1335427&queryText%3DIEEE+Std.+1363a-2004

(last accessed Jan. 30, 2014).

246 The Keyed-Hash Message Authentication Code (HMAC) (2008, NIST, FIPS PUB 198-1) at 

http://csrc.nist.gov/publications/fips/fips198-1/FIPS-198-1_final.pdf (last accessed Jan. 30, 2014).
181

• Symmetric data encryption: Symmetric data encryption is expected to be used for 

two separate purposes within the SCMS. The first purpose, to protect internal SCMS 

entity communications, has not yet been determined. Symmetric data encryption is 

likely to be used because it is more efficient than using asymmetric data encryption, 

for this purpose. But the public-private key pair (asymmetric) would be used to 

distribute the symmetric keys (periodically changed).

The second purpose is to provide a one-way compression of the linkage seeds to convert 

them into the pre-linkage values that are sent to the RA. It uses a keyed hash that offers proof of 

the legitimacy of the linkage authority that created them.

In both cases, the design calls for using the Advanced Encryption Standard (AES)-128.

• Linkage Values: Are generated using SHA-256 and using AES in raw247 mode as input 

to the one-way compression that creates the keyed hash that conceals the linkage seeds 

(as described above).248 Counter with CBC-MAC (CCM) mode”249 is used to randomize 

the initial AES encryption and provide authentication.

Uses of these different cryptographic applications include:

• Basic Safety Message: Digital signatures only are used; the digital certificates 

that a vehicle receives from the SCMS are also attached to BSMs for verification 

purposes. The receiver trusts the message if it can validate the certificate.

• Communications between vehicles and the SCMS: Asymmetric encryption is 

used for confidentiality when a devices needs to reach a component of the SCMS.

Digital signatures are added to show that the request is coming from a valid 

device. Examples include:

o To reach the RA or the MA with a certificate request or misbehavior 

report, a device uses asymmetric encryption to encrypt the content for the 

RA or the MA.

o To show that the certificate request is valid, the device creates a signature 

using the private key corresponding to the public key in the enrollment 

certificate.

o To show that a misbehavior report is valid, the device creates a signature 

using the private key corresponding to the public key in a currently valid 

pseudonym certificate before sending the signed content.

 

247 Also known as Electronic Codebook or ECB mode. 248 As specified in: Recommendation for Block Cipher Modes of Operation (2001, NIST Special Pub. 800-38C). 249 Recommendation for Block Cipher Modes of Operation (2001, NIST Special Publication 800-38C) at 

http://csrc.nist.gov/publications/nistpubs/800-38a/sp800-38a.pdf (last accessed Jan. 30, 2014). Also see the CCM 

Mode for Authentication and Confidentiality (2004, N.W. Group) and Counter with CBC-MAC (CCM) (Sept. 2003) 

both at http://tools.ietf.org/html/rfc3610 (last accessed Jan. 30, 2014).
182

• Communications inside the SCMS (entity to entity): For performance reasons,

communications between the entities use symmetric encryption together with the 

message authentication code (MAC). The symmetric encryption provides 

confidentiality, and the MAC provides integrity. Together, they provide 

authenticity but not non-repudiation (i.e., one entity cannot tell which of the two 

communicating parties generated the MAC). As the SCMS separates ownership 

(power) and data, non-repudiation becomes less of an issue. The only exception is 

the communication with the MA. Here, non-repudiation is required to make sure 

that a request really came from the MA and was not staged by the other SCMS 

entity. The MA is the only entity that needs to digitally sign its requests (as 

opposed to using the MAC); and only during misbehavior investigations. Note the 

keys for symmetric encryption will be distributed to entities within the SCMS 

using their public-private key pairs (that is, in asymmetrically encrypted 

messages).

• Certificates for vehicles and SCMS entities: Digital certificates are used and 

include the linkage values described above.

7. Additional information on the current V2V security system design and research

As evidenced by the research, the current V2V security system has been developed 

through a set of highly technical, incremental decisions. Along the way, outside review by NIST, 

Oak Ridge National Laboratories, and the DOT modal partners in FHWA, FTA, and the Volpe 

Center have questioned decisions, highlighted concerns, and discussed/analyzed new options.

When the research results are viewed holistically, the following statements can be made 

about the system and accomplishments to date:

 DOT and its partners have developed a leading-edge approach to communication 

security, one that will enable trusted messaging, feasible operations, and preserve user

privacy appropriately.

 The approach to security is based predominantly on proven cryptographic methods.

Standards are employed that are tailored specifically for these security purposes; they are 

industry-consensus standards that are being harmonized with Europeans at the ISO250

level.

 A working prototype has been built that proves that the basic, fundamental operations are 

feasible in a real world environment.

 An operational and organizational structure (architecture) is being designed that is 

relatively stable. Most elements are well defined – even to the point of identifying 

number of personnel, number of servers, hardware, etc. But there are new entities that 

still need definition of functions and processes.

 

250 ISO is the International Organization for Standardization.
183

Models show SCMS requirements for resources251 and for bandwidth are 

relatively modest even when scaled up to full deployment.252 While the SCMS 

will be unprecedented in scale for a PKI system, it is not remarkable compared to 

existing IT systems. First year estimates for a few million equipped vehicles 

(equivalent to only a few percent penetration) indicate the need for approximately 

30 high-end computers (processors/servers) and roughly 4500 other pieces of 

equipment like disk drives, monitors, keyboards, personal computers, etc. 

distributed across perhaps 40 facilities. Year 25 estimates for ~300 million 

equipped vehicles, (penetration above 95 percent) indicate the need for roughly 

550 high-end computers and 29,000 other pieces of equipment distributed across 

perhaps 95 facilities. This covers almost all traffic over the entire country. Note 

the specific estimates are rough and preliminary but provide a good ballpark 

understanding of the scale. Data throughputs between entities are estimated at a 

tiny fraction of current data flows for video entertainment, for example.253

 European regulators and industry are using a very similar approach despite focusing on a 

different set of system objectives—mobility and opt-in applications. They have noted that 

they will likely adopt practices from the U.S. design, once finalized, when they look to 

implement V2V safety applications. There is a movement to harmonize on security 

policies at an international level.

 Strength/Validity/Break-ability of the design:

o The design incorporates digital signature algorithms and hash algorithms that are 

NIST compliant and predicted to be strong until sometime in the future. (ECDSA256 is expected to be un-breakable for another 20 years.)

o Some initial work has been conducted with the prototype system in Safety Pilot 

Model Deployment to test the system to see where vulnerabilities exist. Some were 

found as “back-door holes” associated with the system operator and with devices. 

These tests have formed lessons learned that are informing the development of 

certification processes for devices, and are anticipated to be incorporated into 

standard operating procedures, deployment guidance, and policies (including within 

the new RSE specification).

o Planned penetration testing will provide insight into the reliability and resiliency of 

the design.

 

251 Including such resources as hardware, software, energy/power, and personnel.
184

o Notably, costs for breaking the key element of this security approach --ECDSA 

encryption-- is estimated to be very high by security experts254

Research Need IX-2 Cryptographic flexibility

Research Activity: Independent Evaluation of Vehicle-to-Vehicle Security Design

Description: The chosen cryptographic algorithms are estimated to be resilient against 

brute force attack for a few decades with some susceptibility through an 

unanticipated weakness. In the future new algorithms could enable better 

performance but may require redesign of functions or operations within 

the SCMS. Research is needed to determine if and how the existing SCMS 

and overall security solution design should change to build this flexibility 

or modularity into the system.

Target Completion: 2015 (draft report to NHTSA)

Current or Planned NHTSA research addressing this need:

NHTSA will initiate an Independent Evaluation of the Vehicle-to-Vehicle Security Design in 

FY14 (Research Need IX-3) that will include an assessment of the design to support a 

cryptographic algorithm change. 

C. Overview of system integrity and management

Generally speaking, “system integrity” is defined as the state of operating within the 

limitations of mandated (not necessarily by government) or prescribed operational and technical 

parameters, performing its intended function in an unimpaired manner, free from deliberate or 

inadvertent unauthorized manipulation of the system.255 “System management,” in turn, is 

defined as execution of the set of functions required to support a communications network and 

the individuals, activities, or organizations that are the network’s end users. For end users, such 

functions may include registering, verifying, enrolling, credentialing, billing, or revoking 

credentials. For the network, such functions may include controlling, planning, allocating, 

deploying, coordinating, and monitoring the resources of the network; initial network planning, 

frequency allocation, predetermined traffic routing to support load balancing, cryptographic key 

distribution authorization, configuration management, fault management, security management, 

performance management, and accounting management. Such tasks typically do not include 

provision of end user equipment.256 In this case the functions support operations of the Security 

Certificate Management System for V2V communications.

 

254 Vehicle Safety Communications-Applications: Final Report, Appendix Volume 3, at F-45. See

www.nhtsa.gov/Research/Crash+Avoidance/Office+of+Crash+Avoidance+Research+Technical+Publications (last 

accessed Jan. 15, 2014).

255 Federal Standard 1037C (General Services Administration document in support of MIL-STD-188). See

www.its.bldrdoc.gov/fs-1037/fs-1037c.htm (last accessed Jan. 30, 2014). 256 Id.
185

As used in this discussion, the terms “system integrity” and “system management” 

together are intended to encompass all of the functions, activities, and organizations that play a 

role in ensuring the security and trustworthiness of V2V communications and the privacy of 

system users based on the public key infrastructure (PKI) framework and technical design 

produced through joint research by DOT and CAMP. The term “user” refers to users of devices, 

whether original equipment or aftermarket.

The technical requirements for the current V2V communications security design require a 

SCMS made up of individual Certificate Management Entities (CMEs) to administer the security 

functions supporting the connected vehicle system. The term “CME owner/operator” refers to 

the entities that will have legal and operational control over individual organizations that run 

SCMS functions.

To be viable from NHTSA’s standpoint, the SCMS, as a whole, and the individual CMEs 

must satisfy certain key principles established by DOT in 2012:257

• Security and ability to detect and respond to attacks – the system must incorporate 

functions and processes to protect and monitor the systems. These functions must be 

able to identify anomalies and take action if anomalies present a threat to system 

operation.

• Privacy protection at the appropriate level – the system, through design and 

procedure, needs to appropriately protect the identity and daily activity of users of the 

system.

• Support of transportation safety – the system must contribute to supporting the safety 

need.

• Cost-effectiveness – the cost to operate the system must be balanced to the benefit 

attributed to the system.

• Extensibility across applications on a national scale – the system must be expandable 

to support nationwide development of V2V technology.

Both system integrity and system management are critical pre-conditions for safe, reliable 

V2V communications and appropriate privacy protection for users in a V2V-enabled

environment. System integrity, by maintaining the state of the SCMS operation within 

established performance parameters and providing security for V2V messaging without 

deliberate or unintentional unauthorized interference, creates the environment of trust required 

for cooperative safety messaging. Users of the system must be able to trust the content of the 

messages received from other users. System integrity forms the critical basis for that essential 

 

257 Principles for a Connected Vehicle Environment Discussion Document (DOT, April 18, 2012). See

www.its.dot.gov/connected_vehicle/principles_connectedvehicle_environment.htm (last accessed Jan. 30, 2014).
186

trust. At the same time, system management facilitates and enables system integrity by 

performing the set of technical and organizational functions that provide the foundation for 

system integrity.

Elements key to establishing system integrity and management include:

• The System’s Technical Design,

• System Functions,

• System Organization,

• System Ownership and Operation,

• Enforcement of System Integrity and Management, and

• System Governance.

Some of these key elements were discussed in detail in Section IX.B – namely, system 

technical design and system functions – and therefore will not be covered again in this section. In 

the following sections, we address the remaining key system elements in turn. 

Please note that a majority of the content of the System Integrity and Management and 

subsequent governance discussions are based on comprehensive SCMS research by Booz Allen 

Hamilton, detailed in the BAH report entitled Security Credentials Management System (SCMS) 

Design and Analysis for the Connected Vehicle System, dated December 27, 2013.

258

1. Key elements of system integrity and management

Section IX.B describes a technical security system design for initial and full deployment 

in detail. For this reason, the discussion below provides only a brief, high-level summary of the 

aspects of the technical design necessary to support and put in context the subsequent policy 

discussion of System Organization, Ownership and Operation, and Governance. Preliminary 

system costs are addressed in detail in Section XI.

The SCMS technical design reflects the processes associated with certificate production, 

distribution, and revocation. Figure IX-4 above illustrates how the SCMS functions interact with 

each other and with OBE.

As explained in Section IX.B, the SCMS technical design uses a PKI framework to 

achieve the security goals related to establishing trust among users. Using PKI cryptography 

allows for creation and management of digital certificates that certify the sources of messages, 

 

258 Security Credentials Management System (SCMS) Design and Analysis for the Connected Vehicle System

(Booz Allen Hamilton, Inc., Dec. 27, 2013). [Hereafter, “BAH SCMS Design and Analysis Report”]. See Docket 

No. NHTSA-2014-0022.
187

enabling users to trust one another and the system as a whole.259 The use of digital certificates to 

establish trust among users forms the conceptual basis for the SCMS technical design.

At DOT’s request, CAMP researched and developed a phased security system 

deployment design featuring “initial deployment” (for up to 3 years) and “full deployment.” The 

key difference between the two is that not all SCMS functions will be available during initial 

deployment, and there will be no communications between OBE and the SCMS. This approach 

is intended to bring users into the V2V system gradually as connectivity evolves and as some of 

the more complex SCMS functions are developed further and readied for deployment. During 

initial deployment, OBE and Aftermarket devices will download and use three-year batches of 

certificates.

CAMP has put forth 2 options for size of certificate batches and related usage:

• Option 1: Three-year reusable, non-overlapping five-minute certificates

• Option 2: Three-year batches of reusable, overlapping,260 five minute certificates 

valid for one week

CAMP compared the options by assessing implications for privacy,261 security against 

Sybil attacks,262 and certificate storage and generation costs. On the basis of its analysis, CAMP 

found Option 2 as technically preferable to Option 1, primarily because Option 2 protects against 

retrospective linkability of certificates better than Option 1. This characteristic of Option 2 

makes identification of vehicles or their drivers harder and, therefore, in CAMP’s view, provides

less risk to individual privacy. DOT continues to work with CAMP to assess the viability and 

advantages/drawbacks of each option.

The security system design contemplates a hierarchical PKI containing a Root Certificate 

Authority and multiple Intermediate Certificate Authorities. The Root CA is the master root for 

all other CAs; it is the “center of trust” of the system.263 It will issue digital CA certificates to 

subordinate CAs in a hierarchical fashion for use in their authentication within the SCMS so that 

 

259 An Approach to Communications Security for a Communications Data Delivery System for V2V/V2I Safety:

Technical Description and Identification of Policy and Institutional Issues (Nov. 2011, DOT, OST-R, JPO, White 

Paper). See http://ntl.bts.gov/lib/43000/43500/43513/FHWA-JPO-11-

130_FINAL_Comm_Security_Approach_11_07_11.pdf (last accessed Jan. 30, 2014). 260 “Overlapping” means a certificate can be used at any time during the validity period – continuously until it 

expires.

261 How well each option’s specifications prevent a user from being tracked, concurrently or retrospectively – which 

is promoted by using certificates for a limited time without reuse. 262 A Sybil attack involves an attacker using certificates to create the illusion of multiple cars on the road, which can 

be dangerous to OBEs – prevented by allowing only one certificate to be valid at a given time. 263 CAMP, Task 5 Extension: Security Credentials Management System (Draft 0.5, April 2013). See Docket No. 

NHTSA-2014-0022
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all other users and functions know they can be trusted. The Root CA is the only entity that can 

self-sign a certificate – the CAs cannot. All trust for the system components and users is 

inherited and delegated from the Root CA through certificate issuance.

The basic premise is that just as vehicles and infrastructure in the system need to be 

“trusted” through the use of short-term certificates that accompany V2V messages, the SCMS 

functions need to be “trusted” by the vehicles or infrastructure when receiving certificate batches 

from that SCMS function. SCMS functions also need to trust one another. For these reasons, 

most SCMS functions receive their own digital certificates, referred to as “CME certificates.” An 

OBE will examine the CME certificate of any digitally signed message it receives before it 

accepts the message as valid to ensure:

• The certificate has not expired,

• The CME that issues the certificate is trusted, and

• The certificate is not listed on a Certificate Revocation List.

CME certificates do not need to be short-lived like the 5-minute certificates intended for 

the OBE, as trip tracking is not a risk for the SCMS function, because privacy is not an issue 

there. Additionally, not all SCMS functions require CME certificates.

DOT brought Booz Allen Hamilton on board as its consultant to: (1) assess the extent to 

which the evolving security design satisfies mission-based needs and DOT’s Principles for a 

Connected Vehicle Environment, described above; and (2) develop and analyze different 

organizational models for the SCMS and its component CME entities based on the limited and 

full deployment scenarios.264 As part of this work, BAH analyzed alternative CME models, 

taking into account the need for security and appropriate user privacy. BAH also identified and 

evaluated options related to parts of the security system not fully developed, as well as estimated 

preliminary costs associated with the current design. Finally, BAH identified topic areas for 

which further exploration is needed prior to SCMS implementation. The agency agrees that these 

areas represent additional research that will be needed to move forward with an SCMS.

 

264 BAH SCMS Design and Analysis Report.
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Research Need IX-3 Independent Security Design Assessment265

Research Activity: Independent Evaluation of Vehicle-to-Vehicle Security Design

Description: Independent evaluation of CAMP/USDOT security design to assess 

alignment with Government business needs, identify minimum 

requirements, assess the security designs ability to support trusted 

messages and appropriately protect privacy, identify and remove 

misbehaving devices, and be flexible enough to support future upgrades.

Target Completion: 2015 (draft report to NHTSA)

Current or Planned NHTSA research addressing this need:

The Independent Evaluation of the Vehicle-to-Vehicle Security Design will be a comprehensive 

evaluation of the design to identify minimum requirements, assess if and or how USDOT 

requirement are or can be incorporated into the design, assess the design’s security capacity, 

identify security threats the design currently addresses, and identify possible modification to 

improve the design.

Whereas the discussion of SCMS functions in Section IX.B focused on activities and 

communications within the SCMS, the current section discusses the DOT research performed by

BAH (with input from CAMP/VIIC) on development and analysis of SCMS organizational 

options. The purpose of BAH’s research was to generate organizational options for the SCMS by

grouping the SCMS functions in CAMP’s design into legally/administratively distinct entities, in 

order to enable secure and efficient communications and protect privacy appropriately while 

minimizing cost. BAH’s analysis of the organizational options for the SCMS, detailed below,

focused primarily on organizational connections and separations, as well as the closely-related 

process of characterizing functions as “central” or “non-central” (which is intimately tied to the 

issue of system ownership and operation). It also examined the cost, security risk, and/or 

operational/policy implications of the different SCMS models.

BAH began by identifying multiple organizational models that, together, captured all 

possible configurations of the SCMS functions identified by CAMP. DOT initially selected a 

small number of these organizational models for BAH to flesh out. As CAMP’s technical design 

evolved, DOT instructed BAH to reconfigure the models being fleshed out to reflect additional 

SCMS functions added to the SCMS design by CAMP, as well as CAMP’s new categorization of 

functions as either “central” or “non-central.” Based on its independent PKI research, as well as 

 

265 Intelligent Transportation Systems: Vehicle-to-Vehicle Technologies Expected to Offer Safety Benefits, but a 

Variety of Deployment Challenges Exist (Nov. 2013, GAO-14-13). See www.gao.gov/assets/660/658709.pdf (last 

accessed Feb. 12, 2014).
190

new insights into the security design communicated by CAMP, BAH then simplified the initial 

organizational design proposed by CAMP to remove certain organizational separations of 

functions that BAH determined were not necessary for security or privacy reasons. CAMP/VIIC

subsequently agreed that several pseudonym functions (e.g., linkage authorities and RA), 

initially viewed by CAMP/VIIC as needing to be housed in separate legal/administrative entities, 

may reside in the same CME organization without compromising privacy or security 

requirements.

Ultimately, the organization of the SCMS– the final grouping of functions and estimates 

of any efficiencies -- will be controlled by the organization(s) that manage the SCMS and own 

and operate the component CMEs. However, NHTSA anticipates being able to influence the 

organization and operation of the SCMS (and thereby ensure adequate separation to assure 

secure, privacy appropriate V2V communications) through agreement or MOU with the SCMS 

Manager or through participation on an SCMS “governance board,” as discussed further in the 

governance section below.

BAH’s SCMS organizational model/analysis is based on CAMP’s latest SCMS technical

design and represents BAH’s perspective of how functions within the SCMS may be grouped.

Figure IX-4 Security Certificate Management System Organizational Model

DOT/BAH and CAMP/VIIC have somewhat different perspectives on whether certain 

functions with the SCMS should be categorized as “central” (functions that need to be owned 

and operated by a single legal entity) or “non-central” (functions that may be owned and 
191

operated by multiple legal entities). The issue of whether a function is central or non-central has 

significant policy implications both for SCMS Organization and for SCMS 

Ownership/Operation.

CAMP/VIIC has taken the position that the SCMS Manager, Request Coordination and 

MA functions all are intrinsically central. CAMP/VIIC also uses the term “central-by-choice” to 

refer to functions that can be owned and operated by more than one legal entity, but for 

simplicity reside in only one operator/owner. It is our understanding that CAMP believes that the 

same organization(s) that run non-central functions also can operate central functions. CAMP’s 

technical design for the SCMS reflects their division of functions into “intrinsically central,” 

“central by choice,” and “non-central.” 

By contrast, focusing more on concepts of organizational modeling rather than on 

technical requirements, and analyzing from a legal/administrative perspective, BAH does not 

distinguish between “central-by-choice” and “intrinsically central.” Instead, it defines “central 

functions” as those that must be owned and/or operated by a single organization that does not 

own or operate any non-central functions. BAH defines “non-central functions” as those that 

may be owned and operated by multiple distinct organizations. BAH’s organizational model 

reflects its determination, based on conflict of interest principles and PKI best practices, that 

organizations that own own/operate central functions (e.g., the SCMS Manager, ECA, MA) 

should not own/operate non-central functions (such as the PCA, RA, LAs, Intermediate CA, 

LOP, Root CA, certification lab or DCM).

266

CAMP/VIIC has classified the ECA as non-central, while BAH would classify it as 

central if the ECA is involved in collecting any personally-identifying information that could 

link a long-term enrollment certificate to short-term certificates used to authenticate V2V 

messages. This is probably due to the fact that CAMP’s technical security design, in order to 

achieve the CAMP/VIIC’s stated privacy and consumer acceptance goal of “end-to-end” 

anonymity, does not contemplate collection of any information that could link or be used to link 

short-term certificates to an OBE, vehicle or driver. That being said, DOT specifically instructed 

BAH to incorporate into its organizational models various options for linking short-term digital 

certificates to production runs of OBE, OBE, VINs, and drivers for purposes of identifying, 

investigating, and/or recalling potentially-defective V2V equipment.. CAMP also has agreed to 

incorporate into its work technical and organizational options, respectively, that would enable 

collection of information to permit such linkage for these purposes

Currently, NHTSA believes that collection of information linking long-term enrollment 

certificates to production lots of V2V equipment in connection with the bootstrapping process 

 

266 BAH SCMS Design and Analysis Report, Chapter 5 at 45.
192

will satisfy its mission-based information needs (i.e., investigation and recall of defective

vehicles or V2V equipment). This would require some of the CME organizations to work 

together in a way not currently contemplated by CAMP’s latest technical security design, to 

combine information that will link short-term certificates implicated in certain misbehavior 

reports and processes (and therefore emanating from potentially-defective V2V OBE) to 

enrollment/long-term certificates.

As part of its work for DOT, CAMP/VIIC are exploring options for specific processes to 

accomplish this end. Once CAMP proposes such options, NHTSA will work with CAMP and 

VIIC to determine whether the proposed collection and storage processes meet the agency’s 

informational needs and, if so, the extent to which the process options implicate designation of 

the ECA as central or non-central. BAH has emphasized that should linkage with individuallyidentifying information take place, the information collected should exist only within a central 

ECA and should be separated from the Root CA to decrease the possibility of a malfeasant 

insider linking identifying information in the enrollment certificates with the short-term 

certificates used for V2V communications. The agency will analyze the extent to which 

organizational separation of the CME functions required to link enrollment certificates to 

production lots will mitigate any privacy risks stemming from such linkage as part of its 

comprehensive privacy risk analysis, discussed in Section VIII.B.

Organizational separation of functions is an example of a policy control often used to 

mitigate privacy risks in PKI systems – but such separations come with increased costs and may 

negatively impact the system’s ability to identify and revoke the credentials of misbehaving 

devices. Ultimately, other functions may be co-located within the same SCMS component 

organization. However, grouping of SCMS functions and any resulting efficiencies/risk tradeoffs will depend, in large part, on the system’s ownership and operational structure, as well as 

system governance, and on the preferences of the entity or entities that own and operate the 

SCMS Manager and CME component entities.

The SCMS Manager is intended to serve as the entity that provides system management, 

primarily by enforcing and auditing compliance with uniform technical and policy standards and 

guidance for the SCMS system-wide. The uniform standards/guidance will need to establish and 

ensure consistency, effectiveness, interoperability, and appropriate security and privacy 

protection across the CMEs to facilitate necessary communications, sharing of information, and 

operational connections. The SCMS Manager will need to have mechanisms to ensure that all 

CME entities have policies, practices, technologies, and communications consistent with systemwide standards and guidance. The SCMS Manager may (but need not) be the body that develops 

the standards, guidance, or policies applicable system-wide, and would be the entity charged 
193

with overseeing standards and policy compliance by the CME entities that, together with the 

SCMS Manager, make up the SCMS. Technical standards and guidance exist applicable to PKI 

industry-wide that likely will form the basis for many of the policies and procedures applicable 

across the SCMS.267

2. SCMS ownership and operation

SCMS ownership and operation is inextricably linked to SCMS governance, discussed in 

more depth below. In essence, there are three basic organizational models that apply both to 

SCMS ownership and operation and to SCMS governance: public, public-private and private.

Due to the lack of Federal funding available to support an SCMS, DOT research to date has 

focused on the likelihood of private ownership and operation of the SCMS “industry,” with 

governance being largely “self-governance” by private industry participants and stakeholders, 

except to the extent that operational requirements may stem from Federal law, regulation, 

contract or agreement.

As discussed in Section XI below, our preliminary cost estimates for a V2V system 

include the assumption that a private entity would own and operate the SCMS, and impose costs 

that would be covered by increases in the purchase price of new vehicles. For this reason, the 

SCMS organizational structure discussed in the prior section – the organizational separations and 

groupings of functions into legally/administratively distinct CME component entities -- may not 

necessarily be realized in any private SCMS eventually implemented to support connected 

vehicle communications. In the context of a private SCMS “industry,” the organizational 

structure and operation of the SCMS will be determined by private owners and operators of 

CME components, under the oversight of an SCMS Manager (ideally an industry-wide coalition 

of CME owners and other stakeholder representatives who, together, agree on the terms of selfgovernance and system-wide SCMS policies).

DOT and its consultants have identified numerous potential private and public owners 

and operators who could play a role in running one or more of the SCMS functions. However, at 

this point in time, the extent to which any entity would be interested in running one or more 

SCMS functions remains unclear. The list includes:

• OEMs,

• Industry groups (e.g., the American Association of Motor Vehicle, Administrators

(AAMVA)),

• PKI Security organizations and companies,

• Telecommunications companies,

 

267 BAH SCMS Design and Analysis Report, at 29.
194

• State and local government agencies, and

• Academic institutions.

BAH pointed out in its research that ownership and operation of non-central functions 

could take different forms. While there are advantages of having different owners (e.g., 

individual OEMs) oversee large CMEs comprised of all non-central functions, the BAH team has 

suggested that running such an overarching CME should not be a condition of ownership. Thus, 

for example, an entity that wants to own and operate one or more LOPs should not necessarily be 

required to operate all of the other non-central functions.268

BAH’s research also has emphasized that qualifications for ownership and/or operation 

of non-central functions may be very different from those required for ownership and/or 

operation of central functions. For example, due to the critical importance of the security and 

effectiveness of operation of the Root CA, BAH has suggested that the owner/operator of this 

function should have expertise in PKI technology appropriate for the role. BAH also has 

explored the possibility that the OEMs could have a role in the system manager 

function/organization, but in a manner that is legally distinct from ownership/operation of the 

non-central functions that individual OEMs might want to own and operate (e.g., the RA 

functions involving interface with their clients). Shared governance by the OEMs, as through a 

legally/administratively distinct coalition or body, could be consistent with BAH’s 

recommendations for separation of central and non-central SCMS ownership/operation, and 

would have distinct advantages, such as assurance of uniformity in standards and interoperability 

of equipment.269

Should the agency move forward with regulatory action, DOT will need to work with 

CAMP, BAH and potentially others (consultants, interested potential CME owners and 

stakeholders) to perform additional analysis of ownership/operation requirements and candidates, 

and to address the following questions:

• Who will set the various standards, policies, procedures, auditing processes, and other

related industry-wide processes?

• Who are the appropriate candidates for ownership for central and non-central 

functions?

• What are the conditions of ownership?

• Can multiple central functions be combined or operated by the same organization

• To what extent should SCMS owners be required to support V2V and V2X needs as 

the system connected vehicle environment expands?

 

268 BAH SCMS Design and Analysis Report, at 45. See Docket No. NHTSA-2014-0022 269 BAH SCMS Design and Analysis Report, at 45.
195

3. “Enforcement” of system integrity/SCMS manager

Enforcement of “system integrity” is closely related to the general area of SCMS 

governance. In the context of CAMP’s SCMS technical design, envisioned by NHTSA as a 

privately owned and operated “industry,” a private SCMS will enforce system integrity within 

the SCMS through self-regulation and binding agreements with the entities agreeing to be 

regulated. Organizationally, enforcement is the primary responsibility of the SCMS Manager. 

The SCMS Manager provides critical system management by enforcing and auditing compliance 

with uniform technical and policy standards and guidance applicable system-wide. The uniform 

standards/guidance will need to establish and ensure consistency, effectiveness, interoperability 

and appropriate privacy protection across the CMEs to facilitate necessary communications, 

sharing of information, and operational connections, and most likely will be based in large part 

on existing technical standards applicable to PKI systems.

4. “Enforcement” of system integrity/Federal role

In the context of the SCMS technical design, envisioned as a privately owned and 

operated “industry,” we view the Federal role by NHTSA in “enforcing” or otherwise ensuring 

system integrity as fairly limited. Primarily, the agency would perform its traditional regulatory 

role. In addition, NHTSA’s agreement with the CME entities that constitute the SCMS, or the 

SCMS Manager on behalf of those CMEs (if they are inclined to sign an agreement), could 

provide supplemental enforcement or oversight mechanisms, consistent with our authority. Other

Federal entities also likely will have some “enforcement” jurisdiction over aspects of system 

integrity, including the jurisdiction of the Federal Trade Commission over compliance by the 

SCMS entities that interact with end users with their own privacy policies.

Consequently, the specific elements of Federal “enforcement” relating to system integrity 

would include:

• NHTSA compliance and enforcement of the security aspects of a potential FMVSS 

via development of compliance testing procedures and enforcement via the 

manufacturer’s self-certification and NHTSA selection of some items for testing in 

relation to devices identified as motor vehicle equipment;

• NHTSA ODI investigation and recall of potentially defective V2V equipment;

• NHTSA enforcement of Agreements with SCMS Manager (and SCMS entities), if the 

SCMS is willing to enter into an agreement with NHTSA;

• FTC enforcement of the terms of privacy policies against SCMS entities interfacing 

with end users; and

• FCC enforcement of use of spectrum.

Other than as noted here, neither DOT nor NHTSA would assume any new 

“enforcement” responsibilities in the context of the envisioned privately-owned and self-
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regulated PKI “industry” that could support V2V communications in a secure, efficient privacyappropriate way with minimal Federal involvement.

D. System governance and why it is important

Although heavily dependent on context, the term “governance” generally refers to the 

way rules are established, implemented, and enforced. Governance can mean formal regulatory 

oversight by a Federal, State, or local governmental entity. NHTSA’s issuance and enforcement 

of FMVSSs under the Safety Act is an example of governance by a Federal entity. However, 

governance does not always require the participation of a “government” (i.e., a geo-political 

entity). In the context of corporate entities, governance typically refers to consistent 

management, cohesive policies, guidance, processes, and decision-rights for given areas of 

responsibility.

Deployment of V2V technologies will require governance of a wide range of complex 

functions and legal issues. For purposes of this discussion, we have divided these functions and 

issues into two categories: those outside the purview of the SCMS, and those inside its purview.

Areas of governance falling outside of the SCMS (most notably, performance standards and 

requirements, FCC certification requirements, device communications interoperability, and 

spectrum allocation and management) are addressed substantively elsewhere in this decision 

paper. For this reason, the following discussion of “system governance” focuses solely on the 

important policy area of governance of the security system required to support the SCMS.

As used in this discussion:

• “SCMS System” is defined as all the needed functions associated with security 

certificate management for the connected vehicle system – from the SCMS Manager 

down to the individual functions and the component CME entities in which they may 

reside.

• “System Governance” refers to the body or set of bodies/entities that determine 

standards, policies, compliance requirements, and expectations for all organizations that 

have a role to play in certificate management as part of the SCMS that will be needed to 

support deployment of V2V technologies.

System governance encompasses:

• How decisions are made about various policies, standards, requirements, and practices;

• Who has the authority to mandate and enforce compliance with the policies, standards, 

and industry requirements;

• Who makes up the overseeing financial, legal, management, and executive operations of 

the entities in the SCMS;
197

• How various entities interact with each other;

• How the system addresses privacy issues;

• How risk and liability are allocated across the organizations;

• Who will own the intellectual property (data and software) of the system; and

• How the system‘s intellectual property will be licensed or otherwise allocated among and 

between internal and external entities.

The SCMS technical design and related work of the VIIC call for an SCMS made up of a 

central SCMS Manager and various CME component organizations together performing all 

functions required for certificate management. As discussed in detail above, the SCMS Manager 

will define and oversee certain standards, policies, procedures, and operational practices 

applicable to the SCMS component entities. The potential scope or extent of authority and 

operations of the SCMS Manager are still under development, but as in all industries, there are 

three fundamental options for organizational structure from which to choose for SCMS industry 

governance (the same three apply to the inextricably-related issue of SCMS ownership and 

operation):

• Public: governance structure determined and administered by the government, either 

directly or indirectly (as via a contractor)

• Public-Private Partnership (PPP): any organizational structure authorized by law 

within the range between a purely government organization and a purely private 

organization, established and administered in accordance with the authorizing partnership 

or similar document (typically a grant, cooperative agreement or other agreement)

• Private: governance structure established and administered by a purely private 

organization or organizations, without direct government involvement

These governance options have different implications for the level of involvement of the 

Federal Government and stakeholders in the oversight, setting of policies, rules, standards, 

procedures, operational practices, liability/risk sharing, funding, and nature of 

compliance/enforcement within the SCMS industry.

From a Federal perspective, each option also may have certain pros and cons as it relates 

to authority, appropriations, safety, privacy, risk management, and continuity of operations. 

These are briefly summarized below. However, due in large part to the absence of Federal funds 

to support a public SCMS, DOT research on SCMS development to date has primarily focused 

on fleshing out a largely private model of SCMS governance. Based on this research, which has 

generated multiple examples of existing private sector governance organizations, we believe that 

a private model could be a viable mechanism for system governance of the SCMS. NHTSA’s 
198

existing legal authority will accommodate use of a grant, cooperative agreement, or other

agreement to facilitate stakeholder – and even DOT -- input into governance of a private SCMS, 

assuming willingness on the part of the private entity to enter into such an agreement.

The VIIC, under a cooperative agreement with DOT, also has examined the viability of 

each of these models from industry’s perspective, applying the following high-level principles, 

considered by its members as foundational for any governance entity:270

• Participation/voice,

• Accountability,

• Representation,

• Transparency,

• Efficiency,

• Flexibility, and

• Fairness and decency.

While it has not identified a preferred option, based on its governance work for DOT to 

date, the VIIC has taken the position that a private governance organization, without any 

government involvement (i.e., not under government contract, agreement or MOU), will lack 

sufficient authority to make all of the decisions and determinations necessary for appropriate 

system governance of the SCMS.271 The VIIC also has expressed other concerns about a purely 

private governance model, including what it views as lack of stakeholder voice, accountability 

and government oversight; antitrust risks; potentially increasing costs; and “massive liability 

exposure.”272 The VIIC seems open to exploring various PPP models involving minimal 

“authority” passed on by NHTSA via contract, grant, cooperative agreement, MOU, or other

agreement that would enable the SCMS Manager to conduct appropriate governance.

DOT will continue to use existing cooperative agreements with CAMP and the VIIC to 

further explore and develop SCMS governance models. Should NHTSA move forward with 

V2V regulatory action, additional research should include exploration of use of a private 

governance model (as the third option above), with some limited government involvement under 

 

270 In support of these principles, the VIIC cited the DOT June 2011 Governance Roundtable Proceedings (available

at http://ntl.bts.gov/lib/43000/43100/43129/GovRoundtableProceedingsFINAL_9_22_11_v4.pdf , with Section 2.1 

of the UNECE Guidebook on Promoting Governance in Public-Private Partnerships (2008). 271 VIIC Assessment of Key Governance Policy Considerations for a Connected Vehicle Cooperative Safety 

Communications System – Part 1, delivered to DOT on March 13, 2013, at 9. See Docket No. NHTSA-2014-0022. 

Of specific concern to the VIIC are lack of authority to: (1) “compel universal participation”; “set or enforce rules 

applicable to external users and participants”; and “compel[ ] vehicle owners to maintain the ir vehicles in 

compliance with security protocols.” VIIC, SCMS Organizational Policy Study, Interim Report, Dec. 11, 2012, at 

16-17. See Docket No. NHTSA-2014-0022. 272 Id.
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an agreement with the private entity, assuming the entity’s willingness to enter into such an 

agreement. This could facilitate stakeholder input into governance in the context of a privately 

owned/operated and governed SCMS, as this may be a variation on the private governance 

model that addresses some (albeit not all) of the VIIC’s concerns about, and makes more 

palatable to industry the prospect of a privately owned, operated, and governed SCMS.

1. Public model

Under a public governance model, NHTSA would directly house or procure the SCMS 

system required to support deployment of V2V technologies. It most likely would do so through 

one or more service contracts with entities to serve as the SCMS Manager and CME component 

entities. Whether run by NHTSA or by NHTSA service contractors, the IT infrastructure and 

related business processes would be governed by Federal law, as appropriate, including but not 

limited to the Federal Information Systems Management Act, the Privacy Act, the 

Administrative Procedure Act, and the Federal Tort Claims Act. To the extent not already 

determined by applicable Federal laws, governance of the SCMS system would be NHTSA’s 

direct responsibility, the specifics of which would be memorialized in NHTSA’s contracts or 

agreements with its service providers. Such contracts or agreements would need to include 

specific provisions to ensure adequate market access, privacy and security controls, data rights, 

reporting, and continuity of services. Stakeholder input into governance of the security system 

would need to comply with the Federal Advisory Committee Act.

The FAA’s air traffic control system is an example of a direct public governance model.

It has a statutory basis, is funded largely by Federal appropriations, and its ownership, control, 

and operation are subject to Federal laws and procedures. As part of the air traffic control 

system, the FAA has a service contract (one of many with different private entities supporting its 

operations) with a private entity to provide data communications services for the NextGen 

program (including provision of the IT infrastructure required for NextGen communications --

but without such infrastructure becoming Federally-owned). The contractor has a nonexclusive 

legal right to consolidate and sell the data generated by the NextGen communications system. To 

the extent that it does so, the FAA receives a credit against reimbursed costs. The contract 

contains other provisions implementing Federal oversight and control, including oversight over 

security and data rights.

Currently, we believe that NHTSA has sufficient legal authority (under the Vehicle 

Safety Act and the “necessary expense” doctrine) , albeit insufficient appropriations, to enter into 

contracts related to the operation of the Security System required to deploy V2V technologies, if 

NHTSA were to regulate the V2V technologies in vehicles. Arguably, direct Federal operation or 

operation via service contracts would be the most effective mechanisms to ensure appropriate 

security, privacy, and long-term, stable continuity of operations, thereby reducing some of the 

more significant risks stemming from deployment of V2V technologies via an FMVSS 

dependent on a security system not directly regulated by the agency. However, absent substantial 
200

new appropriations – which NHTSA has no plans to seek at this time – NHTSA lacks the 

resources to contemplate public ownership, control, or administration of a system the size and 

scope of the SCMS, as currently conceived. For this reason, DOT research to date has not fully 

explored a public governance model for the SCMS. Due to the current fiscal environment it does 

not seem plausible.

2. Public-private partnership model

Under a public-private partnership model, NHTSA would work with the private sector to 

form a Public Private Partnership (PPP) to operate and/or govern the security functions required 

to support deployment of V2V technologies. Depending on the scope of the agreement, the PPP 

could be limited to the SCMS Manager functions identified in the current CAMP/DOT security 

system model. Alternatively, the PPP could be responsible for owning, financing, and operating 

the Security System, as a whole, including the SCMS Manager and CME component entities. As 

yet another alternative, as discussed below, the PPP could be limited to forming a governance 

board of stakeholders to provide input, binding or not, to the SCMS owners/operators.

DOT and its stakeholders have identified multiple models of PPP entities to help inform 

our research on potential ownership, operation, and governance options for an SCMS. Examples 

include: publicly or privately owned utility models,273 which are complex, highly regulated, and 

require significant public resources to administer: the Internet Corporation for Assigned Names 

and Numbers, which operates pursuant to an Memorandum of Understanding with the 

Department of Commerce that retains in DoD unilateral oversight for some functions and some 

but not all liabilities;274 the End-of-Life Vehicle Consortium operated under MOU among the 

vehicle manufacturers, steelmakers, vehicle dismantlers, vehicle crushers, auto shredders, 

brokers, the environmental community, State representatives and the Environmental Protection 

Agency.275

Due primarily to a lack of current or foreseeable appropriations to support a PPP, DOT 

research to date has not fully explored development of a PPP governance model for the SCMS 

and, instead, has focused on a private model or ownership/operation and governance.

3. Private model

Consistent with our current resources, NHTSA has focused on working with stakeholders 

and DOT consultants to develop a viable model of private governance for the SCMS and its 

CME component entities. Ideally, the basis for the private oversight structure would be a 

 

273 Id. at 9-11. 274 Id. at 4-6. 275 Id. at 13.
201

coalition of CME component entities who, together, constitute and empower an SCMS Manager 

to decide on and enforce standards and processes applicable to the SCMS as a whole.

All organizations within the “industry,” or all organizations that make up different parts 

of the SCMS environment, could be represented. The coalition of SCMS “industry” participants, 

together, could decide on standards, codes of conduct, expectations, and other norms in order to 

maintain and protect communications security, appropriate user privacy, and required operational 

functions within the system, under the auspices of the SCMS Manager and/or another coalitiontype body. In addition, this group likely would decide on and participate in recommendations 

about resource management and costs for the industry and its governing body.

Many commercial industries today operate under this model of private governance, 

establishing private, industry-specific organizations to develop and enforce ethics, standards, 

code-making, and enforcement functions not specifically required by law. The largest benefit of 

this kind of governance structure is that it reduces the involvement of the government and 

therefore reduces the cost to the taxpayers for managing, administering, and enforcing rules 

within and across the CMEs, although the cost will be passed to the consumer at some point. It 

also provides more efficiency and flexibility in decision-making than typically is available in the 

context of a government or PPP model.

The positive and negative implications of a private governance structure include:

• Lower costs and more streamlined implementation/operational processes, due to the lack 

of Federal workplace regulations and processes

• Need for clear monitoring and enforcement standards and processes, potentially with an 

additional level of oversight or review/audit

• Need for agreements across jurisdictions, organizations, and areas of oversight so as to 

ensure smooth operations and reduced communications or collaboration challenges

The private model accommodates some limited Government involvement. Once a 

coalition or other private entity to serve as SCMS Manager is established voluntarily by a private 

SCMS “industry,”276 NHTSA could enter into an agreement with that governance entity to 

ensure that SCMS functions required for V2V safety are delivered by CME entity organizations 

in a way that is consistent with DOT’s Principles for a Connected Environment, discussed above

-- and that such services are made available to all market participants in a secure, ongoing, 

nondiscriminatory, and privacy-appropriate manner. Such agreement also would provide the 

 

276 SIGNIFICANT CAVEAT: This governance analysis hinges on DOT successfully reaching a consensus 

agreement with a willing collation of OEM or another market participant to serve as SCMS Manager or otherwise 

ensure provision of the security system necessary for deployment of V2V technologies.
202

SCMS, as a whole, with the assurance that its activities would be, and would be perceived to be, 

in accordance with those principles.

Assuming willingness by the private entity to enter into such an agreement with the 

Government, either NHTSA or JPO authority might be used to support a mechanism for 

stakeholder input into SCMS governance, formal or informal. This kind of DOT-funded 

“governance” board is similar to what DOT envisions for governance of the NAS-owned 

SHRP2277 databases: no Federal ownership or operation of the data but a group of interested 

stakeholders, including NHTSA and FHWA, on a governance board to establish high-level terms 

of access, security and privacy controls and similar aspects of operation.

Numerous real-world examples exist of organizations/systems in industries that selfgovern through internal, binding contracts and agreements. Typically, such private governance is 

grounded in oversight and inter-organizational practices and agreements that provide the 

governing organization with adequate legal authority to establish and enforce industry-wide 

standards and maintain strong centralized functions, when appropriate. Often industries subject 

to self-governance also are subject to governance by local, State or Federal entities. Examples 

include:

• Aeronautical Radio, Incorporated (ARINC), the sole licensee for the airline 

communications frequency, is an example of a private governance organization identified 

by the VIIC, funded by membership and sponsorship annual dues.278

 

277 The second Strategic Highway Research Program (SHRP 2) was authorized by Congress to address some of the 

most pressing needs related to the nation’s highway system: the high toll taken by highway deaths and injuries, 

aging infrastructure that must be rehabilitated with minimum disruption to users, and congestion stemming both 

from inadequate physical capacity and from events that reduce the effective capacity of a highway facility. These 

needs define the four research focus areas in SHRP 2: (1) the Safety area is conducting the largest ever naturalistic 

driving study to better understand the interaction among various factors involved in highway crashes—driver, 

vehicle, and infrastructure—so that better safety countermeasures can be developed and applied to save lives; (2) the 

Renewal area is developing technologies and institutional solutions to support systematic rehabilitation of highway 

infrastructure in a way that is rapid, presents minimal disruption to users, and results in long-lasting facilities; (3) the 

Reliability area is developing basic analytical techniques, design procedures, and institutional approaches to address 

the events—such as crashes, work zones, special events, and inclement weather—that result in the unpredictable 

congestion that makes travel times unreliable; and (4) the Capacity area is developing a web-based tool to provide 

more accurate data and collaborative decision-making in the development of new highway capacity in order to 

expedite the provision of that capacity while simultaneously addressing economic, community, and environmental 

objectives associated with new construction. SHRP 2 is administered by the Transportation Research Board of the 

National Academies under a Memorandum of Understanding with the Federal Highway Administration and the 

America Association of State Highway and Transportation Officials. For more information, see

www.trb.org/StrategicHighwayResearchProgram2SHRP2/Blank2.aspx (last accessed Jan. 30, 2014). 278 VIIC, SCMS Organizational Policy Study, Interim Report, Dec. 11, 2012, at 15-16. See Docket No. NHTSA2014-0022
203

• Payment Card Industry’s governance via an agreement to adhere the Payment Card 

Industry Data Security Standard. Compliance with the 12 requirements of PCI DSS is 

necessary for merchants to be able to accept cards bearing the logos of the major payment 

card brands. The PCI Security Standards Council maintains PCI DSS, but enforcement of 

the standard is the responsibility of individual payment brands. The ATM Industry 

Association (ATMIA) is an independent, non-profit trade association that supports 

members of the ATM sub-industry through advocacy and education. Although critical for 

doing business, agreement to the PCI DSS is voluntary.279

Other than enforcement of those aspects of governance embodied in any agreement 

between the SCMS Manager and NHTSA, and any input provided via NHTSA’s participation in 

a stakeholder board, as discussed above, under the private coalition model, NHTSA would play 

no further role in the self-governance of the SCMS “industry.” The rules and obligations of 

industry participants would therefore depend on the entities that constitute and subject 

themselves to governance by the organization. A slightly different, potentially less inclusive 

(with regard to decision making) private governance model would result if an individual entity in 

the ITS marketplace, rather than a coalition group, agreed to serve as system manager overseeing 

the CME entities required for V2V safety; an individual entity could be an academic, State, or 

private (for profit or non-profit) organization. Either private governance model could be 

supplemented by a stakeholder “governance board” to establish or suggest policies and practices 

for the SCMS Manager to apply system-wide, to the extent that the private CME 

owners/operators agree to consider or be bound by such input.

With a private system owner/operation, ultimately, the details of internal governance 

(like the details of internal organization) would be up to that private CME entity/entities – in 

particular, the entity serving as SCMS Manager -- and the Federal Government’s role would be 

limited to ensuring that entities honored the terms of their agreement with DOT or NHTSA, if an 

agreement exists. As noted above, that DOT agreement primarily would include a provision that 

the private SCMS’s delivery of security functions required for V2V communications would be 

consistent with DOT’s Principles for a Connected Environment, provide adequate market access, 

incorporate appropriate protection of privacy and security, and involve reporting and sufficient 

continuity of services obligations to ensure the long-term stability and availability of the SCMS.

However, as noted above, the private model could be supplemented with a stakeholder 

governance board to advise on governance issues that NHTSA or JPO likely could support under 

a cooperative agreement or grant for that limited purpose.

 

279 BAH SCMS Design and Analysis Report, at 35-36. See Docket No. NHTSA-2014-0022
204

While the private model possesses considerable benefits, it also carries certain risks that 

the Federal model does not. The primary risk of a purely private model involves continuity of 

SCMS function. With no Federal involvement, the party or parties owning and operating the 

SCMS theoretically could choose to stop doing so at some point. A V2V system needs an SCMS 

to function; if the SCMS owner/operator ceases to provide the security required for V2V 

communications, the V2V system will no longer work. Even with some amount of Federal 

involvement, it remains difficult to compel specific performance if the performing party chooses 

to stop performing. One option for minimizing the not insignificant risk associated with a private 

model, should NHTSA enter into an agreement with a private SCMS owners/operator, is to 

include certain contractual provisions in the agreement. NHTSA can structure the agreement so 

that the private SCMS owners/operator is required to provide sufficient notice of its intent to 

cease providing V2V security services and to continue operating the SCMS until NHTSA can 

identify another entity to assume operations, or so that the Federal Government receives 

liquidated damages in the event of non-performance. Of course, “lights out” also could be a risk 

under a Federal model if Congress suddenly withdraws funding after NHTSA establishes the 

SCMS. In any event, a thorough consideration of contingencies for risks such as this seems 

highly advisable.

4. Scope of the SCMS system governance

In order to define governance policy, it is first necessary to identify the SCMS functions 

that need governing in order to deploy V2V technologies, and why. Please note that there may be 

Federal, State, and local laws applicable to various areas discussed below as appropriate for 

governance. Where relevant, we have attempted to identify the applicable legal authority.

However, as used in this discussion, the term “governance” focuses primarily on those aspects of 

the SCMS and SCMS activities not already addressed by existing laws.

To set the stage for this analysis, following is a brief summary of the industry perspective 

on governance needs, as represented by the VIIC,

280 and of NHTSA’s somewhat different 

perspective.

a) The VIIC perspective

Pursuant to a cooperative agreement funded by DOT, the VIIC has provided to DOT a 

series of white papers summarizing their members’ consensus views on various policy issues 

relating to V2V technologies. Also pursuant to that agreement, the VIIC has provided policy 

support to CAMP in its development of the technical and organizational/operational designs for 

the SCMS. As detailed above, CAMP has designed and the VIIC views the SCMS as a collection

 

280 DOT funded the VIIC’s research specifically to obtain industry’s views on V2V policy issues such as privacy, 

liability, SCMS governance and data ownership.
205 

of functions consisting of multiple organizational groups, specifically, a central SCMS Manager 

and central and non-central CME component entities.281 Unlike DOT consultants, the VIIC does 

not regard as problematic a single CME entity conducting functions that are both central and 

non-central in nature, as long as select functions reside in separate legal entities. The VIIC sees a 

pressing need for a single SCMS Manager with governance authority over the CME component 

entities and the functions that make up the SCMS, listed above. 

The mission of the SCMS Manager would be to: 

 Set SCMS organizational structure 

 Establish operational rules and processes 

 Define means of separation of functions 

 Provide mechanisms for certification, audit, enforcement and adjudication 

 Establish funding mechanisms 

 Provide adequate risk management, and 

 Have ability to address cross-border issues 

The VIIC has indicated that certain key functional areas, both outside and inside the 

SCMS, require the oversight, control and consistency of governance, Table IX-3282

Table IX-3 VIIC Concept of Security Certificate Management System Functional Area Distribution 

Functions outside of the SCMS: Functions Within the SCMS: 

Performance requirements and standards (to be established 

by NHTSA FMVSS) 

Security system (SCMS) internal 

operations and management 

Rules of operation and maintenance 

Rules of use and access to the SCMS 

for devices beyond V2V safety 

Device certification and enforcement (under an FMVSS and 

the Motor vehicle Safety Act) 

Device security interoperability 

What messages and broadcast on what channels 

(FCC/NTIA/Spectrum Manager) 

Privacy 

Device communication interoperability 

(FCC/FMVSS) 

Device certification with the SCMS 

Spectrum Management (FCC/NTIA/Spectrum Manager) Cross-border acceptance and 

international harmonization 

Data access and ownership – usage, security and privacy* Oversight/administrative functions 

Liability Risk Management* Funding 

*According to VIIC but not NHTSA 

 

281 VIIC Assessment of Key Governance Policy Considerations for a Connected Vehicle Cooperative Safety 

Communications System – Part 1, at 16 (delivered to DOT on March 13, 2013). See Docket No. NHTSA-2014-0022. 

282 Id. at 10 et seq. 
206

The VIIC has suggested that the functional areas falling outside of the SCMS, listed 

above, are those that likely will be governed by an FMVSS, the Motor Vehicle Safety Act, a 

spectrum manager, or other standards or entities.283 The additional notes in parentheses 

identifying the likely sources of external governance outside of the SCMS that did not originate 

from the VIIC but were added by NHTSA for purposes of clarity.

b) NHTSA perspective

NHTSA generally agrees with the VIIC’s characterization of the functions that need 

governance outside of the SCMS, with two significant exceptions marked by asterisks in the left 

column of the VIIC chart above: data access and ownership, and liability. To the extent not 

already addressed by existing Federal, State, and local law, we see data access and ownership to 

be squarely within the scope of the SCMS’s governance of privacy and intellectual property/data 

rights through its Privacy Policies – not as an external function. Placement by the VIIC of 

access/ownership and privacy outside of the SCMS is, however, consistent with the VIIC’s 

previously-expressed position that data access/ownership and privacy should be the subject of 

new Federal legislation and regulation designed to implement stringent restrictions on access to 

and use of BSM data broadcast by OBE. The VIIC position is grounded in the OEMs’ concern 

that inadequate privacy protection will adversely affect consumer acceptance of V2V technology 

and, ultimately, new car sales. NHTSA understands that concern but believes privacy can 

adequately be protected through the SCMS.

A second area that NHTSA does not see as needing active or new forms of governance 

outside of the SCMS is that of liability/risk management. In our view, the liability of participants 

in the envisioned V2V warning system already is governed by existing Federal, State, and local 

laws and legal authority, including but not limited to those establishing tort/product liability for 

government and non-governmental entities and individuals.284 The VIIC and NHTSA agree that 

how risk is allocated within the SCMS would be a matter for internal governance under the 

auspices of the system manager function.

NHTSA also agrees with CAMP and the VIIC about the key functional areas within the 

SCMS that will require the oversight, control, and consistency of a sole, central internal 

governance structure. In our view, the critical SCMS functional areas that will need internal 

governance and management are:

• Organizational Structure/Ownership: requirements for functional separation/groupings

and expertise/viability requirements

 

283 Id. at 12. 284 Section X.
207

• Operational Policies and Processes: mechanisms for certification, audit, enforcement, 

and adjudication

• Interoperability: standards for device communications and security interoperability

• Security/Privacy Assurance: certificate policy, including physical, procedural, and 

technical controls

• Privacy/Data Ownership Policy: a policy applicable CME-wide that protects individual 

privacy and data that can be linked appropriately to an individual

However, we note that the latest SCMS design refers to the central internal management 

function as the “SCMS Manager.” For consistency, throughout this discussion we, too, use the 

term SCMS Manager to refer to the function that would undertake internal operations and 

management of the CME component entities by providing policy and technical standards for the 

entire CME “industry.” The SCMS Manager function could be carried out a number of different 

ways. As is often the case in large commercial industries, a volunteer industry consortium could 

take on this role. In other industries, or in public or quasi-public industries, a regulatory agency 

or other legal or policy entity often performs the central management role. In the context of the 

SCMS, we expect that a single legal/administrative entity will take on the SCMS Manager role –

but, as noted above, that entity could function with input from a “governance board” funded by 

DOT via a cooperative agreement or grant, assuming available funds, if the private SCMS 

Manager entity consents to accepting such input on an advisory or ideally a binding basis.
208

X. Legal Liability

A. Overview

Legal liability is a policy issue frequently identified by industry -- and to a lesser extent 

by other stakeholders -- as a potential impediment to deployment of V2V technologies. The 

Federal Government has multiple available tools to limit legal liability, when Congress deems it 

appropriate to do so. If NHTSA moves forward with regulating V2V technologies, the agency 

will need to work with the Department to determine whether to support liability limiting or 

sharing mechanisms that would limit the legal exposure of industry, some or all parts of the 

SCMS, or potentially other stakeholders. However, ultimately, it will be up to Congress to 

determine whether such liability limiting mechanisms are appropriate in the context of V2V 

communications.

The decision options currently under consideration by NHTSA involve safety warning 

technologies -- not control technologies.285 As discussed below, from a products liability 

standpoint, V2V safety warning technologies, analytically, are quite similar to on-board safety 

warnings systems found in today's motor vehicles. For this reason, NHTSA does not view V2V 

warning technologies as creating new or unbounded liability exposure for industry. The agency, 

therefore, does not see a current need to develop or advocate the liability limiting agenda sought 

by industry in connection with potential deployment of V2V technologies via government 

regulation.

One factor that will contribute to NHTSA's assessment of the degree to which liability 

could be an impediment to development of a private SCMS is the extent to which the primary 

and secondary insurance markets make insurance coverage available to CME entities. Another

factor will be the extent to which CME entities are able to limit their legal liability via terms of 

use or similar contractual mechanisms applicable to individuals or entities participating in the 

connected vehicle environment.

B. Industry’s liability concerns and solutions

Throughout the V2V research process, DOT has accessed information about the positions 

of industry members on various V2V policy issues two primary ways: (1) through a cooperative 

agreement between JPO and the VIIC designed specifically to obtain industry’s views on various 

 

285 To the extent that future regulatory action by NHTSA contemplates requiring safety control technologies, 

NHTSA will revisit the appropriateness of advancing liability limiting measures protective of industry and/or other 

stakeholders.
209

policy issues, and (2) through discussions with individual industry members. While the following 

discussion of liability references primarily the positions and views expressed by the VIIC, the 

concerns expressed informally by individual OEMs and manufacturers to DOT officials have 

been largely consistent with that of the VIIC. Not surprisingly, industry is worried that 

deployment of V2V technologies may increase its liability exposure.

The VIIC readily has acknowledged that manufacturers regularly address risk 

management as an integral part of designing and manufacturing vehicles for the real world.286

However, it has suggested that cooperative crash avoidance safety applications present an 

“unprecedented challenge to risk management.”287 VIIC’s position has been that “the design, 

development of ultimate deployment of DSRC-based V2X communications systems creates 

unique risk allocation concerns among the wide range of partisans (both public and private 

sector)” and that risk allocation is “further complicated by the introduction of aftermarket 

devices, the potential for system tampering/hacking, and the risk of unauthorized access to 

networks and to sensitive data.”288 As stated by VIIC, it may be difficult to determine who is 

liable for a V2V system failing to perform as the driver expected, due to the complexity of the 

system and the number of parties involved.289 The VIIC also has noted that a NHTSA regulation 

promulgated under the Safety Act would not provide industry with adequate risk management 

because such regulations do not expressly preempt common law tort liability.290

In support of its position, the VIIC has compared DSRC communications designed to 

enable low-latency safety applications to convenience services provided over commercial 

wireless networks.

291 It concluded that “the potential risk implications for low latency safety 

warnings are substantially higher than exist today for convenience services."292 The VIIC’s 

liability assessment seems to be based, in large part, on the expectation that there will be no 

contract allocating risk among individuals and entities involved in the V2V environment. In the 

context of convenience services, such contracts control the relative distribution of risk among the 

multiple entities involved in providing services. By contrast, as envisioned by CAMP and the 

VIIC, presumably participants in a mandatory V2V safety system would not be required to enter 

into contracts with the security or communications service providers or other participants. In the 

 

286 White Paper on Risk Management Issues, Vehicle Infrastructure Integration Program, VIIC Deployment 

Analysis and Policy Work Order #4, Task 13 General Policy Support, at 2 [Hereafter, “VIIC Risk Management 

White Paper”], delivered to DOT on 4/18/2012. See Docket No. NHTSA-2014-0022. 287 VIIC Risk Management White Paper, at 2. 288 Id., at 1. 289 Task 14 Aftermarket Device Research Addendum (06-30-2010 v3) p. 54, Nov. 8, 2011.[ Need Docket #] 290 VIIC, SCMS Organizational Policy Study, Interim Report, Dec. 11, 2012, at 2. See Docket No. NHTSA-2014-

0022

291 Risk Management White Paper, at 1. 292 Id.
210

VIIC’s view, there would be no contract, legal mechanism, or case law to provide courts with 

guidance on risk allocation.293

In addition to the lack of contractual limitations and legal precedent, other primary 

liability issues identified by the VIIC294 include:

• Whether and, if so, how V2V warning applications increase the risk of liability for 

OEMs, operators, and drivers;

• The need for Congress to put in place one or more legal mechanisms for distributing risk 

among OEMs, operators, drivers, and other public and private stakeholders;

• Whether V2V warning applications will change the way the legal system assesses driver 

versus equipment error; 

• Whether owners may be held legally accountable for shutting off or failing properly to 

maintain V2V warning systems; and

• Whether the human machine interface required for V2V warning systems will increase 

driver distraction in a way that will affect legal liability.

The VIIC has identified as examples of Federal liability limiting mechanisms preemption 

(explicit or implied), immunity (as with 911 services), indemnification (for Federal contractors),

and other types of limitations on damages or ways to allocate risk to government and away from 

industry (other examples of which are detailed in a risk assessment report prepared by the 

Dykema law firm for the VIIC295 under the JPO cooperative agreement).296 The VIIC also has 

noted that “the nature and extent of desired liability protections will depend on the governance 

model chosen and reasonably anticipated legal risks.”297 VIIC has asserted that the greater the 

involvement of the government, the less likely it is that the SCMS’s activities will be challenged 

or exposed to liability for harm to property or persons.

298 In discussions, both the VIIC and some 

specific industry members have tied their support for deployment of V2V safety technologies to 

the Federal Government’s willingness to put in place liability limiting mechanisms. However, 

NHTSA does not believe this is a uniform industry position, in that not all OEMs consider 

liability protection as a condition precedent to going forward with V2V implementation.

 

293 Id. 294 Id., at 2. 295 Dykema, Risk Assessment Report, under contract to VIIC (Policy work order, Task 6, Deliverable 1), Mar. 12, 

2009, at 38-65. [Hereafter, “Dykema Risk Assessment Report”]. See Docket No. NHTSA-2014-0022. 296 VIIC, SCMS Organizational Policy Study, Interim Report, Dec. 11, 2012, at 19. See Docket No. NHTSA-2014-

0022

297 Id. 298 Id., at 26.
211

C. Liability concerns specific to the SCMS 

Specifically with respect to the SCMS, the VIIC has indicated that it views liability risk 

management within the SCMS as a key functional area requiring internal governance.299 The 

VIIC identified the SCMS Manager as the entity with responsibility not only for governing

liability risk management within the SCMS but also for providing liability risk protections to all 

CME entities making up the SCMS.300 The VIIC has taken the position that the Federal 

Government will need to grant to the SCMS broad governance authority (through statute, 

Executive Order, regulation, contract, or other means) – possibly cross-border authority -- and 

has stated that the mechanism through which legal authority is conveyed could provide liability 

protections for central or non-central SCMS elements.301

D. Federal liability limiting mechanisms

The Federal Government has at its disposal a range of mechanisms to limit the liability of 

private and public entities and individuals, when Congress deems it appropriate. Some examples 

of liability limiting mechanisms include:

• Explicit/Implicit Preemption, e.g., under the Federal Motor Vehicle Safety Act;

• Contractual Indemnification via contract or agreement, e.g., indemnification for 

contractors providing hardware and software to update the FAA’s air traffic control 

system under its En Route Traffic Computer Replacement Program; Public Law 85-804, 

the indemnification authority primarily used by the Department of Defense;

• Statutory Immunity, e.g., Federal Volunteer Protection Act, extending immunity 

protections to volunteers affiliated with non-profits provided they do not receive 

compensation in excess of $500 per year;

• Capped Liability, e.g., Amtrak Reform and Accountability Act of 1997, limiting overall 

damages from passenger claims to $200 million from a single railway incident and 

explicitly authorizing passenger rail providers to enter into indemnification agreements; 

Oil Pollution Act of 1990, passed after the Exxon Valdez accident, making oil companies 

responsible only for the first $75 million of liability claims from businesses and 

organizations affected by a spill; and

• Risk Transfer, Insurance Pools, and Reinsurance Programs, e.g., Price-Anderson 

Act, providing for two-level insurance pool covering nuclear power industry; 

 

299 VIIC Assessment of Key Governance Policy Considerations for a Connected Vehicle Cooperative Safety 

Communications System -- Part 1, at 5 (Mar. 12, 2013). [Hereafter, “VIIC Governance Paper”]. See Docket No. 

NHTSA-2014-0022. 300 Id., at 15 and 20. 301 Id., at 19.
212

Commercial Space Launch Act of 1984, requiring insurance up to 500 million cap with 

500 million to 1.5 billion in coverage provide by Federal Government.

These are just a few examples of liability limiting or risk shifting mechanisms. Many 

such programs are hybrids created to address specific catastrophic risks or to encourage 

development and/or deployment of new technologies.

All such programs require Congressional approval. The question for NHTSA is whether 

public and private entities that may be involved in provision of V2V communications, including 

but not limited to the OEMs, will agree to move forward with deployment of V2V 

communications if DOT does not seek and Congress does not approve some form of liability 

limiting/risk sharing program.

E. NHTSA’s assessment of industry liability

Will industry concerns about liability be a stumbling block to regulation of V2V 

technologies? We think not – at least not to the dramatic extent that some industry stakeholders 

have suggested.

Under traditional product liability tort law theories,302 OEMs will be responsible if they

manufacture and sell a defective product that causes harm to a person or property.303 This 

includes liability for design defects, manufacturing defects, and defects due to inadequate 

warnings.304 According to one legal analysis, there are a number of different potential product 

liability claims that could be associated with V2V technologies.305 As stated above, the VIIC has 

suggested that it may be difficult to determine who is liable for a V2V system failing to perform 

as the driver expected, due to the complexity of the system and the number of parties 

involved.306

However, the V2V technology currently under consideration results in safety warnings -

not motor vehicle control. For this reason, ultimately, it is the driver who remains responsible for 

failing to avoid a crash. It will be difficult for a driver to prove that an accident would have been 

avoided had the V2V system functioned properly. Potential liability based on V2V defects, 

 

302 Product liability laws vary from State to State, but a good overview of the relevant common themes in State 

product liability tort law is set forth in the Dykema Risk Assessment Report, at 21-34. 303 Restatement (Third) of Torts Ch. 1 § 1. 304 Restatement (Third) of Torts Ch. 1 § 1. 305 The Dykema Risk Assessment Report identified four groups of likely product liability claims stemming from to 

V2V: (1) OEM failure to deploy V2V; (2) improper installation or location of technology; (3) failure to maintain 

OBE; and (4) claims associate with operation and use of OBE, including OBE failures and claims involving 

operator-OBE interaction. 306 Task 14 Aftermarket Device Research Addendum at 54 (06-30-2010 v3, Nov. 8, 2011). See Docket No. NHTSA2014-0022
213

therefore, will be limited substantially by lack of causation due to drivers’ roles in failing to 

avoid crashes.

A lawsuit also might allege that a crash was caused, in whole or in part, by a failure in the 

communications infrastructure supporting V2V (e.g., an RSE). However, as evidenced by the 

numerous lawsuits claiming that failure of a traffic light contributed to an accident, such cases 

typically are brought against public or quasi-public entities and not against vehicle 

manufacturers.307 For this reason, we would not expect alleged failures in V2V infrastructure to 

impact OEM liability in a significant way.

Significantly, V2V safety warnings are not very different in terms of application or 

interaction with the driver than on-board safety warning systems found in many of today’s motor 

vehicles. Under the existing product liability tort law framework, manufacturers have the ability 

to take steps to limit their legal liability stemming from such on-board systems through a variety 

of mechanisms (e.g., compliance with applicable safety standards, contractual indemnification by 

OBE suppliers, dispute resolution/arbitration clauses applicable to supplies and consumers308).

One important mechanism is provision by the OEM of adequate consumer warnings and 

instructions for using V2V equipment. Such consumer warnings and instructions would 

emphasize the limited role of V2V safety warning technology and explain the limitations of the 

system in the foreseeable operating environment.309 As specifically noted in the Dykema Risk 

Assessment Report:

This approach does not call for a new or unprecedented effort. Newer vehicle models 

currently on the market that are equipped with systems such as lane-departure warning, 

backover detection warnings, and forward vehicle detection typically follow this 

approach in carefully describing the operation and limitation of these systems.

We would expect that manufacturers would follow this same approach to limiting their 

potential liability in connection with V2V warning systems.310

F. NHTSA’s assessment of SCMS liability

Will industry concerns about liability be a stumbling block to creation and operation of a 

private SCMS "industry?" For the reasons discussed below, we think probably not – and 

certainly not to the extent suggested by the VIIC and certain members of the industry.

 

307 Dykema Risk Assessment Report, at 33. 308 Dykema Risk Assessment Report, at 34-38. 309 Dykema Risk Assessment Report at 35 (“these systems differ from traditional technologies because of the 

manner and degree of interdependence on systems outside the host vehicle (other vehicles, RSEs, communications 

systems) and also because they may be affected by roadway, environmental, and other variables over which the 

OEM has little or no control”).

310 Id.
214

As discussed elsewhere in this report, to date, NHTSA has focused on a private model of 

SCMS governance that would not involve Federal funds or a Federal grant of formal legal 

authority to the SCMS or SCMS Manager -- but instead would result from the CME entities 

themselves agreeing to “self-governance” by a central SCMS Manager pursuant to binding 

contracts or agreements. Such industry self-governance by an SCMS Manager likely would

involve the SCMS Manager establishing minimum insurance requirements and/or negotiating, on 

behalf of members, for system-wide insurance coverage. The SCMS Manager also might work 

with the CME entities to determine the appropriate distribution of liability for harm. However, 

the SCMS Manager would not necessarily be the entity responsible for providing liability 

protection to individual CME entities, whether central or non-central, as has been suggested by 

the VIIC. Unless the SCMS Manager worked with the CME entities to distribute risk among 

participants in a way that provides indemnity to some entities, the agency presumes that 

individual CME entities would carry liability insurance sufficient to ensure adequate coverage, in 

accordance with the insurance requirements established by the SCMS Manager.

The agency also anticipates that any contract or agreement between NHTSA and the 

SCMS Manager and/or SCMS entities would be limited primarily to ensuring adequate system 

security and privacy, periodic reporting, and ready access to information need by NHTSA to 

investigate and recall defective vehicles or V2V equipment. Additionally, at this time NHTSA 

does not see the need for a formal grant of legal authority to a private SCMS, either with or 

without some form of contractual liability limitation.

As discussed above, the V2V technology under consideration results in safety warnings -

not motor vehicle control – and, ultimately, it is the driver who remains responsible for failing to 

avoid a crash. For this reason, it will be difficult for a driver to prove that an accident would have 

been avoided had the SCMS security system functioned properly. Potential liability based on 

failures in the SCMS, therefore, will be limited substantially by lack of causation due to drivers’ 

roles in failing to avoid crashes. It also is not clear to the agency why an SCMS Manager could 

not require that individuals and entities participating in an SCMS agree to terms of use that 

would limit the liability of the SCMS and its component entities, either explicitly or via the same 

type of instructions and explanations of system limitations that the OEMs would use to limit 

liability.

Additionally, the automotive industry seems to have significant incentives to help stand 

up and operate several elements of the SCMS, as currently designed, including the RA and 

SCMS Manager. As the only outward facing component of the SCMS, the RA is critical to the 

ability of individual OEMs to maintain control over its customer relationships. As the entity 

charged with establishing and enforcing policies and procedures applicable to all CME entities 

making up the SCMS, the SCMS Manager presumably will promulgate policies directly 

implicating the financial interests of OEMs and other manufacturers, such as liability distribution 

and intra-CME fees (i.e., the costs to motor vehicle and device manufacturers of obtaining 

certificates and certificate-related services (e.g., device type certification and bootstrapping)).
215

While the organizational structure of the SCMS will need to be consistent with anti-trust laws 

and sound conflict of interest principles, the VIIC’s governance deliverables to date consistently 

have reflected industry’s interest in having a strong voice in SCMS governance (which, in the 

context of the CAMP SCMS design, means a strong voice in the operation of the SCMS 

Manager). Industry’s voice in governance cannot be assured unless it plays a significant role in 

standing up and operating a private SCMS.

Nevertheless, the agency believes that it is premature to take a position on the need for 

liability limiting mechanisms applicable to some or all CME components of the SCMS in order 

to encourage the establishment and operation of a private SCMS to provide security for V2V 

communications. As noted by the VIIC, the appropriateness of such liability limiting/risk sharing 

measures will turn on the constitution and governance of the SCMS. Another factor affecting 

NHTSA’s assessment of whether liability could be a stumbling block to development of a private 

SCMS will be the extent to which the primary and secondary insurance markets will make 

insurance coverage available to CME entities.
216

XI. Preliminary Cost Estimates of V2V Implementation

A. Overview of preliminary estimated V2V costs and benefits

The preliminary estimates explored in this and the following sections are based on 

currently emerging, prototype V2V technologies and existing data. The agency would expect 

these estimates to be revised when more advanced technologies and additional data are available 

for inclusion in an analysis. This and the following sections on benefits and cost-effectiveness 

are considered a minimal analysis of three potential scenarios with current, prototype V2V 

technology. The agency would need to conduct a more comprehensive regulatory impact 

analysis if there was a need to support any such action.

This section details the process of how the agency estimated preliminary costs for 

potential V2V technology deployment. The following section, Section XII, describes the 

preliminary benefit analysis.

The preliminary cost and benefit estimates are provided for three pre-determined 

technology implementation scenarios. These estimates provide a wide range of cost and benefits 

of a potential V2V implementation. The cost in this analysis comprises four categories: vehicle 

equipment, fuel economy impact, communications costs, and SCMS. Together, we estimate that 

the total cost per vehicle to the consumer for each vehicle will be approximately $341 to $350 in 

2020 (across the 3 percent to 7 percent discount rates and three scenarios). This amount is 

projected to decrease over time to an approximate range of $209 to $227 by 2058. Of the four 

cost categories, the initial vehicle component cost is estimated separately for new vehicles and 

old vehicles. The component cost is $329 per new vehicle in 2020, and it will decline 

progressively to $186 to $199 in 2058. The fuel economy impact is estimated to be $9 to $18 per 

vehicle. The communications costs range from $3 to $13 per vehicle, with an average cost of 

$8.30 to $8.50. The component cost (i.e., aftermarket safety devices) per old vehicle range from 

$160 to $387. The SCMS costs range from $1 to $6 per vehicle with an average of $3.14. The 

SCMS cost will increase over time due to the need to support an increasing number of vehicles 

with the V2V technologies.

The total preliminary annual costs (the sum of the four categories of costs) of the V2V 

system fluctuates year after year but generally show a declining trend. The estimated total annual 

costs range from $0.3 to $2.1 billion in 2020 with the specific costs being dependent upon the 

technology implementation scenarios and discount rates. The costs peak to $1.1 to $6.4 billion 

between 2022 and 2024, and then they gradually decrease to $1.1 to $4.6 billion.
217

B. Discussion of V2V preliminary cost estimates

Based on the agency’s preliminary assessment, the total annual costs of the V2V system 

will vary substantially from year to year. In addition to the on-board equipment (OBE) costs of a 

V2V system (i.e., the components that need to be installed on a vehicle to support the V2V safety 

applications operating in the system), there are also costs for fuel economy impacts, the SCMS, 

and communication between the SCMS and OBEs. These cost estimates are highly influenced by 

the technology implementation pace. Therefore, the agency used three different implementation 

scenarios (i.e., the rate at which new vehicles and aftermarket devices are purchased each year) 

to illustrate the potential total costs and the annual impact of establishing a V2V system. These 

three scenarios range from an aggressive implementation schedule that includes aftermarket 

devices and 100 percent implementation for new vehicles in three years, to a relatively slower 

implementation schedule that does not have aftermarket devices and with a maximum of 25 

percent of full implementation. Across the three scenarios and two discount rates (3 percent and 

7 percent), the estimated total costs rise from $0.3 to $2.1 billion in 2020 to a total of $1.1 to 

$6.4 billion in 2022, and gradually decrease to a relatively stable level of $1.1 to $4.6 billion.

Breaking down those annual cost estimates, NHTSA currently estimates, based on our 

preliminary information, that the on-board equipment necessary to support the V2V safety 

applications would cost $329 per vehicle in 2020, with the possibility that these costs will 

decrease over time as manufacturers gain experience producing this equipment (a phenomenon

known as the “learning curve”). Given the various sales scenarios considered, we believe that the 

price per vehicle could be as low as $260 in 2022 and $186 in 2058, as discussed in more detail 

below.

In addition to the cost of purchasing/installing the V2V equipment, there are fuel 

economy costs due to the weight of the V2V equipment. The agency estimated that V2V 

equipment will increase each vehicle’s total weight by approximately 3.45 pounds.

Consequently, it will increase fuel costs by between $9 and $12 for passenger cars over the 

lifetime of the vehicle, and $11 to $18 for light trucks.

The next cost category is the secure communications cost which is the cost of ensuring 

secure communications between vehicles and the SCMS and among the SCMS operations. For 

the first 3 years, based on our assumptions about certificate issuance and delivery, no 

communications will occur to renew certificates. Further, due to the low overall V2V penetration 

rate among the operational vehicles, the agency believes that the probability of misbehavior is 

extremely low and thus the need for a secure communication is not critical. There are, therefore, 

no communication costs for the first three years. In year 4, the average per-vehicle cost to pay for 

communication is estimated to be $8.58 to $10.74, with the price potentially as low as $3.37. At 

its peak, the per-vehicle cost increases to $12.39 to $12.97, with an average fee that could be 

charged to vehicles sold from year 4 through the next 37 years ranging from $8.30 to $8.50.
218

The final cost is that of the SCMS itself, which will ensure that vehicles will be able to 

distinguish trustworthy message sources from those that are not, and, thereby, ensure that the 

V2V system operates most effectively. We anticipate that the initial and ongoing cost of this 

SCMS can be covered with a one-time fee of $3.14 per new vehicle sold. In other words, 

supporting the functions of the SCMS would add an additional $3.14 to the cost of each vehicle 

sold.

In summary, supporting the functions of the SCMS and communications would add an 

estimated additional $11.44 to $12.64 to the average cost of each vehicle sold.

Table XI-1 Summary of Preliminary Costs per Vehicle

Cost category Amount in dollars

Vehicle Equipment Costs $329 in 2020, decreasing to

$186 to $199 in 2058

Fuel Economy Impact $9 - $18

Security Credentials Costs $3.14

Communications Costs $8.30 - $8.50

Total Costs $341 to $350 in 2020, decreasing to

$209 - $227 in 2058

C. Projected vehicle equipment costs

To fully evaluate the vehicle equipment costs, we first estimate the costs for the 

following potential system configurations.

• Original Equipment Manufacturer:

o Full V2V system installed in new passenger vehicles (passenger cars and light 

trucks)

• Aftermarket:

o Retrofit: connects to the vehicle’s data bus, sends and receives BSM, and 

provides advisories/warnings

o Self-contained: does not connect to the vehicle’s data bus and only uses a wire 

to get power from the vehicle, sends and receives BSM, and provides 

advisories/warnings

o Vehicle Awareness Device: uses a wire to get power from the vehicle, sends 

out but does not receive BSM, and does not provides advisories/warnings

Second, we consider three technology sales scenarios that represent potential rates at 

which these V2V systems can be adopted into the vehicle fleet. Finally, we apply our knowledge 

of learning (the potential savings that manufacturers can realize due to their experience 

producing the equipment), based on the three sales scenarios, to show what potential final 

equipment costs can be.
219

1. OEM devices

For V2V systems installed on vehicles as original equipment, our preliminary estimates

are based on confidential information provided by two suppliers. Relying on that information, 

NHTSA estimates that the cost to install the supplier equipment into the vehicle will result in a

per-vehicle cost to the consumer of $342.80 ($327.13 + $15.67) in 2012 dollars. As shown in 

Table XI-2, below, we anticipate that the equipment at the supplier level will cost $216.79, while

the installation will cost $10.38. After accounting for the retail price equivalent of 1.51, which 

includes the additional costs necessary before the product reaches the consumer, and also for the 

reduction in costs due to the current installation rate of GPS units (meaning that if GPS is already 

present on a vehicle, the addition of V2V technology does not require another GPS unit), we 

estimate the increase in per-vehicle cost will be $329.14 in 2020. We further explain our 

estimates for the supplier costs, installation costs, and GPS market penetration in separate 

sections below.

We anticipate that manufacturers and suppliers will realize cost savings over time due to 

additional experience in manufacturing V2V safety equipment; however, any potential cost 

savings due to this additional experience are not included in cost tables until after these effects 

are discussed in the section titled “Learning,” below.

Table XI-2 Summary of Likely Costs in Year 1 for New Vehicles (2012 dollars)

Variable Costs311 Consumer Costs312

Supplier Costs $216.79 $327.13

Installation Costs $10.38 $15.67

Minus Current GPS Installation $9.20 $13.89

Total $217.97 $329.14

a) Variable costs to OEMs

As shown in the “Total” row in Table XI-3, below, our current preliminary estimate is 

that the V2V equipment that suppliers provide to OEMs will cost $216.79.

As discussed in Section V.B.2, we assume that two DSRC radios and two DSRC 

antennas are necessary: One DSRC to send and receive the BSM, and a second to handle security 

aspects of receiving certificates, the certificate revocation list, etc. The supplier cost estimate of 

$130 for 2 DSRC transmitters and receivers is composed of $70 for the first DSRC and $60 for 

the second. The $10 reduction in cost for the second DSRC was based upon the assumption that 

 

311 “Variable costs,” in the table, refer to the direct cost – that is, the cost of the parts and materials – to the 

manufacturer to include this technology in a vehicle.

312 “Consumer costs” refer to the variable costs plus the fixed costs that the manufacturer incurs and passes forward 

to the consumer.
220

the two DSRCs would be packaged together, thereby resulting in lower labor in assembling this 

combined package at the supplier, as well as lower parts costs to package them together rather 

than individually. No such assumption was made for the antenna, since these have to remain 

physically separate in order to avoid interfering with each other.

Table XI-3 Likely Supplier Costs to OEM

Component Weight313 Cost

(in lb.) (2012 dollars)

DSRC Transmitter/Receiver (2) 0.65 130

DSRC Antenna (2) 0.44 10

Electronic Control Unit 0.55 45

GPS 14

GPS Antenna 0.22 4

Wiring 1.20 9

Displays 0.17 4.79

Total 3.23 216.79

Our information on the variable costs to OEMs, when they are purchasing supplies, is 

based on data received from two suppliers in response to a voluntary request for cost information 

sent to eight suppliers of V2V equipment. In order to help ensure consistent production 

estimates, we asked the suppliers to prepare their cost estimates based upon the assumption of 

high-volume production (i.e., meaning at least 250,000 sales per make/model), in order to model 

the expected production that would result if, sometime in the future, the agency required V2V 

and if all light vehicle sales were thus affected. This assumption helped ensure consistent 

estimates across suppliers who responded, since low volume sales result in very high initial 

prices, and if each responding supplier had picked a different volume of sales, the responses 

would not have been easily comparable. Again, assumptions regarding the learning curve will be 

applied later in the analysis.

We made several adjustments to the information we received from the two suppliers to 

arrive at the above estimates. First, the agency has changed some of its assumptions since 

requesting information from these suppliers (e.g., we now believe that two DSRC radios and two 

DSRC antennas are necessary, rather than one DSRC radio and one DSRC antenna). Second, the 

suppliers provided estimates relating to costs of equipment they supplied, but these estimates did 

 

313 Because this table is the first time we break out the costs of the individual pieces of in-vehicle V2V equipment, 

we also use this table to roster the weight of each of the individual pieces as well as the cost of each of the individual 

pieces. See Section XI.C.1.b) below for discussion of the impacts to consumer benefits of increasing vehicle weight.
221

not necessarily include costs for driver warnings for the safety applications that would use V2V, 

nor did they include labor and wiring necessary for the OEM to install the equipment into the 

vehicle. The information from the suppliers was thus incomplete for our current purposes, and 

more assumptions were needed in order to provide a more complete estimate of costs.

We also assumed that all vehicles would already have the FCW application in them by 

the time V2V was required in vehicles, given that the agency anticipates counting the costs and 

benefits for that application as part of a separate regulatory effort.

314 Thus, additional costs for 

displays and wiring to displays were not assumed for FCW for purposes of this analysis, 

meaning that the preliminary costs (and benefits) associated with requiring V2V technology are 

slightly lower (albeit only $1-$2) than they would have been without this assumption.

b) Preliminary Consumer costs

The costs in Table XI-3 reflect the preliminary estimated costs that the OEM pays to the 

supplier to obtain these components. However, they do not reflect the cost of these systems to 

consumers. Table XI-4 provides preliminary consumer costs for these supplier parts. To obtain 

consumer costs, the costs to the OEM for each variable are multiplied by 1.51 to estimate a retail 

price equivalent (i.e., consumer cost). The agency uses the 1.51 markup to represent fixed costs 

(research and development, selling and administrative costs, etc.), as well as OEM profits, 

transportation costs, and dealer costs and profits. Additional costs to consumers (e.g., installation 

costs) are estimated separately and further discussed later.

Table XI-4 Preliminary Consumer Costs (for just supplier parts) Per Vehicle (2012 dollars)

Component Consumer Cost

(2012 dollars)

DSRC Transmitter/Receiver (2) 196.3

DSRC Antenna (2) 15.10

Electronic Control Unit 67.95

GPS 21.14

GPS Antenna 6.04

Wiring 13.59

Displays 7.24

Total 327.13

 

314 This assumption may change. If NHTSA does not require FCW in a regulatory action prior to any V2V 

regulatory action, the costs of benefits of FCW may, at least in part, be attributed to V2V.
222

c) Additional Detail on Preliminary Display Costs

A further breakdown of costs that are already included in Table XI-3 and Table XI-4 is 

provided in Table XI-5 below, where additional detail on our estimates for weight and costs of 

displays are shown. Cost information gathered for displays include both manufacturer-produced 

and supplier-provided displays, as well as different types of displays (e.g., display lights, 

malfunction lights) that can be used by the safety applications to inform drivers of potential 

dangers identified by V2V communications. One such display, a heads-up display (i.e., one 

displayed on the windshield in the driver’s field of vision), is a more expensive system, as shown 

in the cost tear-down results for two heads-up display systems (see Table XI-5 below).

Table XI-5 Preliminary Estimates of Display Costs (2012 dollars)

Weight (lb.) Variable Costs Consumer Costs

Five display lights315 .05 $1.00 $1.51

Malfunction light316 .01 $1.29 $1.95

Light bar .20 $2.50 $3.78

Total .26 $4.79 $7.24

Info. not used

Heads-up display Volvo S8317 .17 $6.91 $10.43

Heads-up display Ford Taurus318 .16 $12.67 $19.13

Warnings can be presented to the drivers via different modalities (e.g., auditory, visual, 

haptic) and for our analysis, the following assumptions and inclusions were made:

• Auditory Displays: We did not include any cost for audible warnings at this time, 

based on the assumption that any audible warnings required for a V2V system would 

use existing audible warning equipment already in the vehicle at that point. If more 

refined warnings were to be required, that would add costs.

• Visual Displays: We assume very simple visual display lights for five applications, 

including EEBL, DNPW, BSW/LCW in the A-pillar or side view mirror (one display 

for both, but one on each side), and LTA. Wiring to these displays is considered 

separately. We assume a much more complex light bar for IMA (like one used in a 

 

315 Five display lights is an assumption for purposes of analysis. 316 Cost and Weight Analysis of Advanced Frontal Airbag Systems (Final Report, Volume 1, Docket number

NHTSA-2011-0066-0001). See www.regulations.gov/#!documentDetail;D=NHTSA-2011-0066-0001 (last accessed 

Jan. 29, 2014).

317 NHTSA FCWS Final Report, at 61/103 (May 16, 2012). See

www.regulations.gov/#!documentDetail;D=NHTSA-2011-0066-0011 (last accessed Jan. 29, 2014). 318 Id., 49
223

V2V demonstration vehicle that would be situated along the top of the dash next to 

the windshield and run up the A-pillar a little), that would attract the driver’s eyes 

toward the direction of the encroaching car.319 We also assume that a malfunction 

light would be required to tell you that the V2V system is not working and you should 

have your vehicle serviced.320

• Haptic Displays: It is also possible that some manufacturers might choose a haptic 

display. Even though the agency has no cost estimates for haptic displays, we believe 

haptic displays would typically be more costly than the displays we have included in 

this analysis.

d) Preliminary Installation cost estimates

The main installation cost is labor, but there are also some costs for materials used in the 

installation of the vehicle equipment (e.g., minor attachments such as brackets or plastic tie 

downs to secure wires). In the table below, estimates for installation costs are separated into 

“Material Costs” (for the minor attachments), “Labor Costs,” and “Variable Burden” (i.e., other

costs that are not direct labor or direct material used in the part, but are costs that vary with the 

level of production, such as set-up costs, in-bound freight, perishable production tools, and 

electricity). We estimate that the variable cost to OEMs to install the V2V equipment is $10.38 

and that the cost to consumers will be $15.67 given the 1.51 RPE (See Table XI-6, below). Note 

that the weight of the installation materials is assumed to be 0.1 pounds.

Table XI-6 Preliminary Installation Cost Estimates (2012 dollars)

Part Material

Cost

Labor

Cost

Variable

Burden

Total

Variable

Total

Consumer 

Cost

DSRC Transmitter/Receiver 0.03 1.25 0.81 2.10 3.17

DSRC Antenna 0.03 0.10 0.07 0.20 0.30

Electronic Control Unit 0.02 1.78 1.15 2.95 4.45

GPS 0.03 0.10 0.07 0.20 0.30

GPS Antenna 0.03 0.10 0.07 0.20 0.30

Wiring 0.18 0.88 0.57 1.63 2.47

Five Displays + Malfunction Disp. 0.00 0.61 0.39 1.00 1.51

Light Bar 0.03 1.25 0.81 2.10 3.17

Total 0.36 6.07 3.94 10.38 15.67

 

319 Some manufacturers might choose to use a heads-up display system for V2V warnings, but the agency does not 

consider it necessary at this time, and it has therefore not been included for purposes of the current analysis. See 

Section XI.C.1.c) for further heads-up display costing information. 320 The agency notes this would be a minimal approach to malfunction indication and that other, more explicit, 

malfunction warnings could potentially be developed.
224

Generally, the ideal source of information for installation costs is a cost teardown study.

However, we do not have a teardown study for V2V parts, in part because there are no 

production-volume systems yet to analyze: it is difficult to tear down something that does not 

exist. Thus, we examined a similar installation cost-estimation teardown analysis. Installation 

costs were taken from a 2012 report titled “Cost, Weight & Lead Time Analysis of Lane 

Departure Warning Systems and Lane Keeping Systems Technology Associated with Passenger 

Vehicles,” by Lieberman & Associates.321 While the parts are not the same, we believe that the 

process for installing these parts would have similar material, labor, and variable burden costs. 

The cost estimates in this report are in 2011 dollars, so they were multiplied by the GDP deflator 

(115.338/113.369 = 1.0178) to bring them up to 2012 dollars.

Specifically, in this report, costs are estimated for installing back-up systems (e.g., a 

camera, ECU, displays) into six different make/models of vehicles. While the system examined 

in the Lieberman & Associates report contains different components from the V2V system (e.g., 

the V2V system uses a DSRC radio instead of a camera), we believe that the installation burden 

for these components is similar. With both systems, manufacturers receive these components 

from suppliers and are installed using similar tools.

In addition to using the cost estimates from the Lieberman study, a few assumptions were 

made in our analysis. For wiring, we assumed a variable labor cost of $21.14.322 We also 

assumed that these new wires would be combined with other wiring harnesses, so the 

incremental cost would be the time to identify and hook up the wires, at 10 seconds per wire to 

hook up both ends and with a total of 15 separate wires that would need to be installed (seven for 

displays and malfunction lamp and eight between the two DSRC radios, two DSRC antenna, 

GPS, GPS antenna, amplifier, and ECU).

e) Current GPS installation rate

While the supplier costs and the installation costs are both costs that are incurred in order 

to install the components necessary to support V2V safety applications, many vehicles are 

already being equipped with GPS units. For those vehicles, the GPS component of the V2V 

system is not a cost that is attributable to the V2V system, since the current information available 

 

321 Docket No. NHTSA-2011-0066-0033. See www.regulations.gov/#!documentDetail;D=NHTSA-2011-0066-

0033. Available at 

www.regulations.gov/contentStreamer?objectId=09000064811e9b8c&disposition=attachment&contentType=pdf

[Note: There is a discrepancy in the title of this report, one version of which omits the word “Weight.”]

322 Production Occupations, 51-2099 Assemblers and Fabricators, Motor Vehicle Manufacturers (Bureau of Labor 

Statistics, May 2012). See www.bls.gov/oes/current/oes512099.htm (last accessed Jan. 28, 2014).
225

to the agency indicates that navigation-grade GPS units are sufficient for the V2V safety 

applications.

For MY2011, NHTSA estimates that about 50 percent of the new light vehicle fleet has

GPS (and a GPS antenna) in their vehicle (see Table XI-7 below). This estimate is based on: (1) 

information about vehicles with navigation systems, which is contained in Wards Automotive 

Yearbook 2012 that has MY2011 data on factory-installed equipment such as navigation (NAV); 

and (2) assumptions about OEM Automatic Collision Notification systems (like OnStar), which 

have GPS as part of the system. An estimated 18 percent of MY2011 light vehicles have 

navigation systems. In addition, a high proportion of BMW, Ford, and GM vehicles have ACN, 

and other manufacturers (Toyota and Hyundai) have similar systems. However, we do not have 

information on what percent of their vehicles are covered now. It is nevertheless likely that more 

than 50 percent of the new light vehicle fleet already have GPS, and would not need to spend 

additional money on GPS for V2V. This estimate of the current market penetration of GPS 

systems is, therefore, subtracted from the total costs of equipping all vehicles with V2V safety 

applications in this analysis. However, if the data indicate that more advanced GPS systems are 

necessary, then we would need to revisit these cost assumptions.
226

Table XI-7 Estimated Percentage of GPS in the New Vehicle Fleet

Passenger Cars LTV TOTAL

MAKE NAV 

%

NAV + 

ACN 

EST.

MAKE NAV 

%

NAV + 

ACN 

EST.

MAKE NAV 

%

NAV + 

ACN EST.

BMW 22% 100% BMW 39% 100% BMW 31% 100%

CHRYSLER 24% 24% CHRYSLER 24% 24% CHRYSLER 24% 24%

FORD 5% 80% FORD 14% 80% FORD 11% 80%

GM 7% 90% GM 18% 90% GM 14% 90%

HONDA 12% 12% HONDA 38% 38% HONDA 25% 25%

HYUNDAI 8% 8% HYUNDAI 7% 7% HYUNDAI 8% 8%

JAGUAR 100% 100% JAGUAR 100% 100%

LAND 

ROVER

84% 84% LAND 

ROVER

84% 84%

MAZDA 6% 6% MAZDA 35% 35% MAZDA 15% 15%

MERCEDES 54% 54% MERCEDES 66% 66% MERCEDES 61% 61%

MITSUBISHI 8% 8% MITSUBISHI 14% 14% MITSUBISHI 10% 10%

NISSAN 15% 15% NISSAN 39% 39% NISSAN 24% 24%

PORSCHE 35% 35% PORSCHE 37% 37% PORSCHE 36% 36%

SAAB 10% 10% SAAB 10% 10%

SUBARU 6% 6% SUBARU 41% 41% SUBARU 28% 28%

SUZUKI 6% 6% SUZUKI 0% 0% SUZUKI 5% 5%

TOYOTA 8% 8% TOYOTA 24% 24% TOYOTA 15% 15%

VW 10% 10% VW 48% 48% VW 14% 14%

VOLVO 35% 35% VOLVO 35% 35% VOLVO 35% 35%

TOTAL 11% 36% TOTAL 23% 59% TOTAL 18% 49%

f) Summary of new vehicle V2V weight and cost estimates

Table XI-8 summarizes the variable and consumer costs for original equipment 

manufacturers for the first year. Costs are assumed to decrease in years after the initial year 

based on the learning curve.

Table XI-8 Summary of Cost Estimates in Year 1 for New Vehicles

(2012 dollars)

Weight (lb.) Variable Costs Consumer Costs

Supplier 3.23 $216.79 $327.36

Installation 0.36 $10.38 $15.67

Subtotal 3.59 $227.17 $343.03

Minus Current GPS Installation 0.14 -$9.20 -$13.89

Total 3.45 $217.97 $329.13
227

2. Aftermarket devices

Preliminary costs are estimated for the three possible aftermarket V2V systems described 

in Section XI.C: Retrofit, Self-contained, and Vehicle Awareness Device (VAD).

The same two suppliers provided cost estimates for these three types of aftermarket 

devices. NHTSA asked them to provide estimates assuming both that they were sold 

individually, and in groups of 1,000 units to retailers or to other large purchasers. NHTSA 

developed likely estimated costs for these three types of aftermarket devices, using these 

estimates and other NHTSA estimates based on the same rationales used previously to estimate 

new vehicle costs. The next three tables show the estimated consumer costs.

Basic assumptions used in each of these estimates are:

• For aftermarket devices sold individually, we assumed a markup factor of 1.5 from 

variable costs to consumer costs; 

• For aftermarket devices sold as an order of 1,000 or more products, we assumed a 

markup factor of 1.3 from variable costs to consumer costs;

• That the learning curve will apply to aftermarket devices also, since their main 

components will be the same as the OEM components of DSRC transmitter/receiver and 

antenna.

Table XI-9, Table XI-10, and Table XI-11 provide the estimated consumer component 

costs and weight for all three aftermarket device types. These are just equipment costs and do not 

include the costs of installing the equipment into used vehicles.
228

Table XI-9 Estimated Consumer Cost of Aftermarket Equipment – Retrofit Device (2012

dollars)

Component Weight Cost Per Unit for

(in lb.) 1 Unit 1,000 Units

DSRC Transmitter/Receiver (2) 0.65 $144 $124.8

DSRC Antenna (2) 0.44 15 13

Electronic Control Unit 0.55 67.5 58.5

GPS 0 21 18.2

GPS Antenna 0.22 6 5.2

Wiring 0 15 13

Displays 0 22.5 19.5

Total 1.86 291.00 252.20

Table XI-10 Estimated Consumer Cost of Aftermarket Equipment – Self-Contained Device 

(2012 dollars)

Component Weight Cost Per Unit for

(in lb.) 1 Unit 1,000 Units

DSRC Transmitter/Receiver (2) 0.65 $114 $98.8

DSRC Antenna (2) 0.44 15 13

Electronic Control Unit 0.55 67.5 58.5

GPS 0 21 18.2

GPS Antenna 0.22 6 5.2

Wiring 0 12 10.4

Displays 0 10.5 9.1

Total 1.86 246.00 213.20
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Table XI-11 Estimated Consumer Cost of Aftermarket Equipment – Vehicle Awareness 

Device (2012 dollars)

Component Weight Cost Per Unit for

(in lb.) 1 Unit 1,000 Units

DSRC Receiver 0.325 $52.5 $45.5

DSRC Antenna 0.22 7.5 6.5

Electronic Control Unit 0.55 0 0

GPS 0 16.5 14.3

GPS Antenna 0.22 4.5 3.9

Wiring 0 0 0

Displays 0 0 0

Total 1.32 81.00 70.20

a) Installation of aftermarket equipment

We believe that a trained technician is likely to be needed to install aftermarket 

equipment properly, since, as learned during the Safety Pilot Model Deployment, it is not so easy 

to determine where to attach antennas on the vehicle to ensure their effectiveness.323 Typical 

installation times would depend on the type of aftermarket equipment. For this analysis we 

estimated one hour for a VAD, one hour and fifteen minutes for a self-contained device, and one 

hour and 30 minutes for a retrofit device. These time estimates were derived from installation 

times from the Safety Pilot Model Deployment. We also assume that a dealership would be the 

typical place where aftermarket devices could be installed. We estimate that the average charged 

wage rate at a dealership is about $90 per hour;324 installation costs would likely be different if 

the devices were installed somewhere else.

b) Summary of aftermarket cost estimates

Table XI-12 presents preliminary consumer costs for Aftermarket in year 1, including 

both equipment cost and installation costs. The equipment costs will be affected by the learning 

curve, but installation costs (which are just labor) will not be affected by the learning curve.

 

323 Somewhere near the center of the roof, near the center of the vehicle appears to be the ideal location for the 

antenna to be able to pick up GPS and to talk to each other. The angle of the antenna is also important for receiving 

and appropriately transmitting information. This becomes difficult to determine when the shape of the roof of each 

make/model is different.

324 Based on Service Repair Facility Average Hourly Labor Rates. See

www.mechaniconduty.com/MapGraphic_email.pdf (last accessed Jul. 14, 2013). These appear to be repair rates 

from a 2009 phone survey of rates charged in particular cities, one per state. No national estimate was provided.

Thus, this is a rounded number considering that we expect repair rates in rural areas to be less and rates for 2012 to 

be higher than the survey results.
230

Table XI-12 Aftermarket Consumer Cost Estimates for Year 1 (2012 dollars)

Equipment Installation Total

Retrofit 252.20 135 387.20

Self-contained 213.20 112.5 325.70

VAD 70.20 90 160.20

3. How the preliminary projected vehicle equipment cost estimates were developed

a) Technology implementation scenarios

As mentioned above, we assume that the costs of the equipment needed to support V2V 

safety applications will decrease over time due to learning (the ability of manufacturers to realize 

cost savings due to their experience manufacturing the product). Thus, the costs that were 

estimated without including learning in the earlier sections will decrease over time if learning is 

considered. Because the effect that learning has on equipment prices is based on the cumulative 

production of the system (i.e., the total number of systems that have been produced since the 

system first became available for sale), we need to know what the projected sales of these 

systems will be in the future.

For the purposes of this analysis, we examined three scenarios of future V2V technology 

sales/implementation using MY2020 as the base vehicles that first have the technology. Scenario 

1 presents a relatively aggressive technology implementation schedule that includes the 

installation of aftermarket devices. These aftermarket installations are assumed to be made on the 

existing relatively recently-sold model year (i.e., MY2015-2021) vehicles, but these aftermarket 

installations are not applied until year 2022 for a subsequent 5-year time period.

Scenario 2 presents a slower pace of technology implementation than that in Scenario 1. 

Furthermore, Scenario 2 does not have aftermarket device installation. Scenario 3 presents the 

slowest implementation and lowest among the three scenarios. Scenario 3 not only does not 

include the aftermarket device, its implementing rate also reaches only to a maximum of 25 

percent as opposed to the 100 percent for Scenarios 1 and 2. These scenarios were all based on 

the projected future new vehicle sales developed by the agency. The projection starts at 

approximately 17 million per year in 2020 and increases to 20 million in 2050, remaining flat at 

the 2050 level thereafter. This projection is based on historic R.L. Polk registration data and 

vehicle sales from 1973 to 2012 using a linear regression statistical process.

The following summarizes the three scenarios. We note that the dates selected here are 

simply assumptions made for the convenience of this analysis, and reflect no judgment by the 

agency on timing or phase-in requirements.

(1) Scenario 1:

• 35 percent -70 percent-100 percent vehicle equipment phase-in starting in MY2020

• 100 percent installation of two safety applications for those with vehicle equipment 
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• Aftermarket deployment for MY2015-2021 vehicles (applicable vehicles)

o Starting 2022 and continuing for a total of 5 years 

o 5 percent of applicable vehicles for 2022 and 2023

 For example, for year 2022, applicable old vehicles include the survived 

MY2015-2019 vehicles, 65 percent of the survived MY2020 vehicles, and 30 

percent of the survived MY2021 vehicles. Five percent of these vehicles 

would be equipped with an aftermarket device

 For year 2023, the applicable old vehicles include 95 percent of those 

applicable old vehicles that were defined for year 2022 and would survive in 

year 2023.

o 10 percent of applicable vehicles for 2024-2026

o The estimated number of aftermarket sales for the 5 implementation years in this 

scenario are: 

 4.70 million in MY2022,

 4.37 million in MY2023,

 8.09 million in MY2024,

 7.06 million in MY2025, and

 6.11 million in MY2026.

• ASD and VAD are assumed to have an equal penetration rate each year. 

(2) Scenario 2 

• 35 percent-70 percent-100 percent vehicle equipment phase-in starting in MY2020

• 50 percent installation of two safety applications for MY2020-2022 vehicles that have 

vehicle equipment, 60 percent for MY2023, 70 percent for MY2024, 80 percent for 

MY2025, 90 percent for MY2026, 100 percent for MY2027 and later. 

• No Aftermarket deployment

(3) Scenario 3 

• 5 percent vehicle equipment for MY2020, 15 percent for MY2021, 25 percent for 

MY2022 and newer vehicles 

• 100 percent installation of two safety applications for those vehicles that have vehicle 

equipment

• No Aftermarket deployment

In order to keep preliminary costs consistently applied, when we summarize costs, 

aftermarket costs will be applied in the year that the aftermarket equipment is purchased even 

though it will not line up with the model year. For example, in 2023, we assume that aftermarket 

equipment will be purchased for a certain percentage of MY2015 through 2021 vehicles. That 

cost is spent in calendar year 2023, and will look like it is spent on MY2023 vehicles in the 

summary costs. The preliminary benefits will be applied by model year, since scrappage (i.e., the 
232

scrapping of discarded objects) is dependent upon model year, not when aftermarket equipment 

is purchased. This has a very small impact on overall costs by model year and only affects 

Scenario 1.

Table XI-13 below shows the number of sales of V2V equipment in new vehicles by 

model year (starting in 2020) for the three scenarios. As described earlier, Scenarios 1 and 3 

assumed that the V2V equipment would already have the IMA and LTA applications. Scenario 2 

has a separate rate for V2V equipment and applications.

Table XI-13 V2V Technology Sales Assumptions in New Vehicles (Millions of Vehicle)

Year Model Year Scenario 1* Scenario 2 

Equipment

Scenario 2 

Applications

Scenario 3*

1 2020 5.96 5.96 2.98 0.85

2 2021 11.94 11.94 5.97 2.56

3 2022 17.21 17.21 8.61 4.30

4 2023 17.32 17.32 10.39 4.33

5 2024 17.41 17.41 12.19 4.35

6 2025 17.56 17.56 14.05 4.39

7 2026 17.65 17.65 15.89 4.41

8 2027 17.78 17.78 17.78 4.45

9 2028 17.94 17.94 17.94 4.49

10 2029 18.05 18.05 18.05 4.51

11 2030 18.22 18.22 18.22 4.56

12 2031 18.37 18.37 18.37 4.59

13 2032 18.50 18.50 18.50 4.63

14 2033 18.61 18.61 18.61 4.65

15 2034 18.79 18.79 18.79 4.70

16 2035 18.97 18.97 18.97 4.74

17 2036 19.14 19.14 19.14 4.79

18 2037 19.31 19.31 19.31 4.83

19 2038 19.47 19.47 19.47 4.87

20 2039 19.66 19.66 19.66 4.92

21 2040 19.88 19.88 19.88 4.97

22 2041 20.17 20.17 20.17 5.04

23 2042 19.51 19.51 19.51 4.88

24 2043 19.62 19.62 19.62 4.91

25 2044 19.72 19.72 19.72 4.93

26 2045 19.83 19.83 19.83 4.96

27 2046 19.94 19.94 19.94 4.99

28 2047 20.05 20.05 20.05 5.01

29 2048 20.16 20.16 20.16 5.04

30 2049 20.27 20.27 20.27 5.07
233

31 2050 20.38 20.38 20.38 5.10

32 2051 20.38 20.38 20.38 5.10

33 2052 20.38 20.38 20.38 5.10

34 2053 20.38 20.38 20.38 5.10

35 2054 20.38 20.38 20.38 5.10

36 2055 20.38 20.38 20.38 5.10

37 2056 20.38 20.38 20.38 5.10

38 2057 20.38 20.38 20.38 5.10

39 2058 20.38 20.38 20.38 5.10

*for both equipment and safety applications

b) Learning

As stated earlier, the preliminary cost estimates we listed above for originally-equipped 

V2V systems and aftermarket systems do not take into account the potential cost savings that 

manufacturers will realize over time. As we show in the following paragraphs, the effect of 

learning can lead to a significant reduction in the costs over time. If we use any of the technology 

sales scenarios described in the previous section (i.e., the differences between them would be 

slight) and assume that V2V equipment production begins in 2020 with a price of $329, the costs 

can range from $249 to $273 in 2022, and $185 to $199 in 2058. The estimated effect of learning 

to prices for aftermarket devices would decrease by 12 percent in 5 years, from $387 to $341 for 

a retrofit device, $326 to $287 for the self-contained device, and $160 to $141 for a VAD.

D. Projected fuel economy impact – fuel costs for increased weight

In addition to the cost of the equipment itself, the new equipment on vehicles will 

increase the vehicle weight. Since the increase in weight is relatively small, the increased weight 

will have only a small impact on the fuel economy of the individual vehicles on which the V2V 

equipment is installed. Nevertheless, over the lifetime of these vehicles, this impact on fuel 

economy will create a cost for society. Our preliminary estimates indicate that (depending on the 

discount rate) the fuel economy impact on passenger cars will be between $9 and $12 over the 

lifetime of the vehicle. For light trucks, we believe the impact will be a cost of $11 to $18 over 

the lifetime of the vehicle.

The impact of added weight on lifetime fuel economy is a function of mileage, survival 

probability (i.e., the percentage of the vehicle fleet that will not be scrapped due to an accident), 

the price of gasoline, the change in vehicle fuel economy due to the added weight, and the 

discount rate chosen to express lifetime impacts in their present value. A sample calculation for 

passenger cars is:
234

Equation XI-1 Projected Fuel Economy Impact Calculation

∑=

+ −

37

1

.8 [( * )/( /( 1)) * *.80 ( * )/ *.80] * n

n n n n pn dn V S w w fe V S fe

Where:

n = Year

V = Vehicle miles traveled

S = Survival probability

w = Baseline vehicle weight

i = Incremental weight from adding V2V – 3.45 pounds

fe = Baseline EPA fuel economy

.80 = Factor to derive on-road fuel economy from EPA fuel economy

p = Fuel price

d = Mid-year discount factor

Each of the aforementioned variables is determined by different sources.

1. Fuel price and estimated miles per gallon

The projected price of gasoline was taken from the Energy Information Administration

Annual Energy Outlook 2013 early release. This source enables us to project the likely price of 

fuel between now and 2057. In our cost estimates, fuel taxes are excluded since these are a 

transfer payment and not a cost to society. Gasoline prices and baseline fuel economy levels are 

projected to increase steadily throughout the time period, which means that the impact of the 

additional weight due to installation of V2V systems will change with every model year.

However, unlike with fuel prices, we do not have baseline fuel economy estimates past 

2025. Thus, estimates of the impact on fuel prices over the lifetime of the model year were 

examined for 2020 and 2025. For years beyond 2025, we assume that vehicles will have the 

same baseline fuel economy and weight as the vehicles from MY2025. The baseline miles per 

gallon figures for passenger cars and for light trucks are shown in Table XI-14. These estimates 

reflect a weighted average based on standards in effect for those years.
235

Table XI-14 Estimated Miles per Gallon (MPG) Values

2020 Passenger Cars Light Trucks

Baseline mpg on EPA test 45.1 32.8

Baseline weight (lb.) 3240 4397

2025

Baseline mpg on EPA test 52.1 37.6

Baseline weight (lb.) 3240 4397

2. Vehicle miles traveled and survivability

NHTSA uses VMT by age of vehicle and survivability tables to model the retirement of 

older vehicles as time passes and to estimate the impact of fuel economy changes over the 

lifetime of a model year. Both VMT and survivability data differ between passenger cars and 

light trucks.

325

3. Incremental weight from V2V equipment

In addition to receiving preliminary information on the vehicle equipment costs (as 

discussed above) from the confidential business information submissions by suppliers, we also 

received information on how much the V2V equipment is likely to weigh. As discussed in Table 

XI-3, above, the V2V equipment is likely to weigh approximately 3.23 pounds. In addition (as 

shown in Table XI-15), we estimate that the warning display components and installation 

materials will weigh approximately 0. 36 (= 0.26 + 0.1) pounds. Thus, our current estimate is 

that the V2V equipment necessary to support the V2V safety applications will increase the 

vehicle weight by 3.59 pounds. Taking into account the reduction of GPS, the net increase in 

weight is estimated to be 3.45 pounds. The increased weight is the same for both passenger cars 

and light trucks.

 

325 The survival rates (see Table A-6) were derived using the 1997-2010 R.L. Polk, National Vehicle Population 

Profile (NVPP). The methodology for deriving these survival rates was published in NHTSA’s technical report

“Vehicle Survival and Travel Mileage Schedules,” Office of Regulatory Analysis and Evaluation, NCSA, Jan. 2006 

(Docket No. NHTSA-2005-22223-2218). See www.regulations.gov/#!documentDetail;D=NHTSA-2005-22223-

2218 (last accessed Jan. 29, 2014). Polk’s NVPP is an annual census of passenger cars and light trucks registered for 

on-road operation in the United States as of Jul 1 each year. Survival rates were averaged for each vehicle age and 

up to 30 years. A polynomial model was fitted to these data using regression analysis to establish the relationships 

between age and the proportion of cars or light trucks surviving to that age.

For vehicle miles traveled, data from the 2009 National Household Travel Survey (NHTS) was used for 

this analysis. Approximately 300,000 vehicles were included in the 2009 NHTS to estimate the average number of 

miles driven by household vehicles at each vehicle age. An earlier survey, 2001 NHTS, was used in the 2006 NCSA

technical report cited above.
236

Table XI-15 Summary of Incremental Vehicle Weight Due to V2V Equipment

Category Weight

V2V Equipment Weight 3.23 lb.

Warning Display Weight 0.26 lb.

Installation Materials 0.10 lb.

Minus Current GPS Installation -0.14 lb.

Total Incremental Weight 3.45 lb.

4. Summary of fuel economy impact

Based on all the above information (i.e., on vehicle miles traveled, survivability, 

projected fuel prices, projected fuel economy, and estimated increased weight), we believe that 

the impact on fuel economy will be as follows. For MY2020 passenger cars, we estimate that 

there will be a $12 increase in fuel used over the lifetime of the vehicle at the 3 percent discount 

rate, and $9 at the 7 percent discount rate. For MY2020 light trucks, we estimate that there will 

be an $18 increase in fuel used over the lifetime of the vehicle at the 3 percent discount rate, and 

$11 at the 7 percent discount rate. See Table XI-16, below.326

Table XI-16 Impact of weight increase on fuel economy over the lifetime of the model year 

vehicle (per vehicle cost for 3.45 lb. increase)

MY2020 Passenger Cars Light Trucks

3% Discount Rate $12.38 $18.56

7% Discount rate $9.51 $11.90

MY2025

3% Discount Rate $11.76 $17.70

7% Discount rate $9.04 $11.36

It appears that the improvement in fuel economy from 2020 to 2025 results in a decrease 

in the fuel costs, even though there is an increase in the price of fuel during the time period.

While we do not have estimates of fuel economy levels or average baseline weights of vehicles 

in the fleet past MY2025, we will assume that the impact of the weight increase on fuel economy 

will stay relatively constant over the time frame.

E. Preliminary system communication costs

The DOT’s Intelligent Transportation Systems Joint Program Office contracted Booz 

Allen Hamilton to perform a cost estimate for the communication costs. BAH provided the 

 

326 We have not calculated any improvements to fuel economy that may result from potential V2V and V2I 

applications. As briefly discussed in Section II.B.5, however, the agency expects there will be V2I mobility 

applications that provide fuel economy benefits. These benefits would be likely to significantly exceed these costs.
237

following report: “Communications Data Delivery System Analysis for Connected Vehicles: 

Revision and Update to Modeling of Promising Network Options.”327 In addition, BAH provided 

a Microsoft Excel file, titled “Cost Model for Communications Data Delivery System (CDDS),”

that lays out the cost estimates (based on preliminary information) in a spreadsheet format, 

which allowed NHTSA to make changes to assumptions as needed and calculate costs

accordingly.

328 This report takes the BAH technical report and focuses on the cases we feel are 

most reasonable, and presents them in a more plain language format. The next several paragraphs 

lay out the assumptions behind these estimates.

When a V2V-equipped vehicle is on the road, it will give a computerized message 

stating, “I am here, this is how fast I’m going, and so on . . . You can trust me.” That last part of 

the message, where the vehicle says “You can trust me,” is important. At the same time, the other

vehicle’s V2V system will be listening for the message, and it needs to know that the message is 

from a good source. In order to meet the agency’s security needs, BAH assumed that PKI will be 

used.

As part of PKI, each vehicle is given a set of digital certificates, and the certificates 

broadcast by the device are assumed not to contain codes that could uniquely identify a vehicle 

like a license plate would. These anonymous certificates were assumed to last for only 5 minutes, 

so even if someone wanted to track a device by its certificate with sophisticated and expensive 

equipment, it would be even more difficult to do so for longer than 5 minutes, when the vehicle 

starts using a completely different certificate. This makes the system harder to break into and 

makes it very hard to track vehicles.

Also, under the current security model,329 every vehicle’s V2V system would keep a list 

of “misbehaving” certificates that it encounters. While the approach to misbehavior has not been 

decided, one method could be that any time bad V2V information is sent, due to an error or due 

to intentional human tampering, the certificate tied to that bad V2V data would be recorded and 

later uploaded when the vehicle transmits data to the SCMS. This way, the SCMS that handles 

the certificate knows which vehicle is misbehaving, and is able to put together a list of all the 

certificates that vehicle currently has available. Then, when vehicles connect to the system, they

will be warned about these misbehaving vehicles with a list of certificates to avoid trusting. That 

list is called the Certificate Revocation List.

 

327 BAH CDDS Final Report. See Docket No. NHTSA-2014-0022. 328 Cost Model for Communications Data Delivery System (CDDS) (Excel File) at Docket No. NHTSA-2014-0022. 329 As discussed in Section IX, NHTSA plans to continue researching security options, including those that may be 

significantly less costly due to decreased reliance on burdensome distribution of CRLs.
238

Assuming a PKI system is used and based on the preliminary security system design used 

in this report, communications between the OBE and to the SCMS or “phone home” include the 

following activities.

• UPLOAD - a request for new certificates

• DOWNLOAD - new certificates

• UPLOAD - a misbehavior report

• DOWNLOAD – a full/partial CRL

• and conduct other data functions or system updates

The next several paragraphs detail the cost factors for these communication activities.

1. Certificate revocation list 

The CRL is a list created by the SCMS that identifies vehicles that are sending out 

messages that are misbehaving. These vehicles could be sending out messages that erroneously 

alert drivers of other vehicles, either intentionally or from misbehaving sensors. BAH has 

outlined several ways by which vehicles may be added to the CRL, as presented below.330

• Administrative revocation, which would be based on a pre-determined set of criteria,

not based on actual misbehavior. For example, vehicles that are formally retired, or 

otherwise determined to be removed from the system for non-misbehaving reasons, 

could make up entries on the CRL.

• Vehicles that observe other vehicles distributing obviously erroneous messages report 

those vehicles. These observations would be based on plausibility checks that would 

verify if the message content made physical sense.

• All vehicles report any received message that results in a positive application action 

(i.e., any message that provides an alert to the driver and a commensurate action). For 

example, if an in-vehicle application issued a warning to the driver based on a 

received message, that message would be sent to the Misbehavior Authority (MA).

This approach would identify as misbehaving vehicles that were emitting messages 

that passed plausibility checks but were potentially erroneous to the extent that they

were causing a large number of warnings.

• Vehicles randomly select received messages to send to the MA, and the MA would 

seek to identify trends and patterns from the randomly sampled messages.331

 

330 BAH CDDS Final Report at 47 at Docket No. NHTSA-2014-0022 331 Unless the sampling rate is high, the overall effectiveness of this approach is uncertain. If the misbehavior rate is 

1% (maximum assumed level), and the sample rate is 1%, the n this approach will, on average, detect 0.01% of the 

misbehaving vehicles, assuming the detection process is 100 percent effective. If the sample rate is higher, the n the 

sampling process will represent a greater data load than the CRL.
239

• It is also possible that a vehicle could self-report if it determines that it is not 

operating properly, and this might also result in a revocation.

BAH has outlined several problems that could arise as a result of misbehaving messages. 

If a message is received from a vehicle that is on the CRL, that message is ignored. However, if 

it is not on the CRL, the message would need to be checked for misbehavior. BAH has outlined 

the responses to these scenarios.332

• The result of receiving a message from a legitimate, non-misbehaving vehicle will 

depend on the vehicle situation.

o If the data in the message indicates a danger, then the vehicle warning system will 

take positive action (warn the driver).

o If the data in the message indicates no danger, then the system will take no action 

(no warning will be issued).

• The result of receiving a message from a misbehaving vehicle that is not on the CRL and 

which passes the plausibility tests will also depend on the vehicle situation.

o If the data in the message indicates a danger, then the system will take positive 

action (warn the driver).

o If the data in the message indicates no danger, then the system will take no action 

(no warning will be issued).

Attacks on the CRL have been considered by BAH. The BAH CDDS final report

recognizes four types of attackers.

333

• A1 (Clever Outsider): A talented engineer and/or cryptographer who does not possess 

any inside knowledge.

• A2 (Knowledgeable Insider): An insider who possesses detailed knowledge about the 

system (security and non-security related) and has access to its specifications.

• A3 (Funded Organizations): An organization that has access to substantial resources 

and furthermore possesses the capabilities of attacker A2.

• A4 (Certificate Authority insider): An insider who possesses detailed knowledge 

about the system and has access to confidential information at the CA level. A4 is an 

insider at the CA and as such compromises the root of trust of the V2V 

communication system.

o Because it is the CA’s responsibility to guard against such an attacker, A4 

is considered out of scope.

 

332 BAH CDDS Final Report at 49 at Docket No. NHTSA-2014-0022 333 BAH CDDS Final Report, at 51 at Docket No. NHTSA-2014-0022
240

Finally, BAH referenced a DOT report that identified two primary security risks:334

• Attacks on the user/risks to safety and user acceptance: these attacks are aimed at 

users and directly impact user safety and indirectly impact system acceptance.

• Attacks on the communications system/risks to privacy: these attacks could either 

(1) track the location and driving routes of a person; (2) cause the a vehicle to be 

falsely reported for misbehavior, causing a valid driver to be removed from the 

system.

Other types of attacks, such as cyber-attacks across the entire vehicle fleet, have been 

considered but not yet addressed. These attacks will be addressed at a later date.

For the Communications Data Delivery System (CDDS), CAMP and BAH have made 

several considerations regarding design and implementation. CAMP has considered a twophased deployment strategy, with the first phase being “initial deployment” and the second phase 

being “full deployment.” Initial deployment refers to the first three years of SCMS 

implementation. The key distinction between the two phases is that in the initial deployment 

stage, “communications between devices and SCMS will not be generally available...” 335

because the communication network will not be established.

Initial deployment is assumed to last for three years, and requires that OBEs on newly 

manufactured vehicles download a three-year batch of certificates. These batches would include 

reusable, overlapping five-minute certificates valid for one week. The term “overlapping” in this 

context refers to the fact that any certificate can be used at any time during the validity period. 

The batches would be good for one week and at this point are assumed to be around 20 

certificates per week, which equates to 1,040 for one year of certificates. As the frequency of the 

certificate download batch changes for full deployment, the number and therefore size of the 

certificate batches also changes accordingly.336

Certificate Updates – the download frequency of certificates at full deployment has yet to 

be determined. However, BAH did consider download size. For option 1, the largest download 

would be 3,000 certificates (for any frequency of downloads), and the largest download for 

 

334 An Approach to Communications Security for a Communications Data Delivery System for V2V/V2I Safety: 

Technical Description and Identification of Policy and Institutional Issues (FHWA, Nov. 2011) at

http://ntl.bts.gov/lib/43000/43500/43513/FHWA-JPO-11-130_FINAL_Comm_Security_Approach_11_07_11.pdf

(last accessed Jan. 29, 2014). 335 BAH CDDS Final Report, at 22 at Docket No. NHTSA-2014-0022. 336 BAH CDDS Final Report at 15 at Docket No. NHTSA-2014-0022.
241

option 2 would be 6,000 certificates (with a three-year download). BAH also considered 2-year 

downloads.

Misbehavior Detection – the BAH preliminary cost analysis assumed that the device 

would perform a plausibility check on incoming messages. If the message is deemed 

implausible, the device would report it as misbehaving. This report would then be checked by the 

Misbehavior Authority of the SCMS, which would revoke the misbehaving vehicle’s certificates 

if the report was deemed to be accurate.

Certificate Revocation and Certificate Revocation List – the revocation process has not 

yet been finalized. The BAH analysis assumed that any devices that are misbehaving would be 

added to the CRL, which would be sent to the OBE at regular intervals. After certificates expire, 

they would be removed from the CRL.

Internal Blacklist – This would be used by the SCMS to make sure that an OBE asking 

for new certificates is not on the revoked list. If a vehicle or device is on the list, no certificate 

updates will be issued.

2. Alternative communication systems

Two definitions are needed to prevent confusion among terms:

• Roadside Equipment (RSE) – refers to communication equipment on the side of the 

road designed to receive and send communications between vehicles and the SCMS 

regarding certificates, CRL, etc.

• Infrastructure Equipment (I) – refers to equipment on curves or at intersections 

designed to communicate information about the road or whether a light is green or 

red, etc. to a vehicle.

For system design specifications, BAH considered three network protocols, cellular, 

hybrid, and DSRC for the CDDS. The three protocols are based on different combinations of 

network technology that may be used by the CDDS.

• Cellular. This protocol would use an almost-all cellular network for the 

communications between the SCMS and the OBE on the vehicle. BAH also included 

an option to use satellite communication for a way to distribute the CRL. However, 

satellite communication is even more expensive than cellular, and was not considered 

further. BAH also noted that this protocol does not use RSE. It uses DSRC for V2I (if 

the infrastructure already has the DSRC antenna in it) and V2V safety 

communications.

• Cellular/Wi-Fi/DSRC - Hybrid. The second protocol would use combinations of 

more technologies – OBE, RSE, cellular, and satellite. DSRC and Wi-Fi would be 
242

used when beneficial, while cellular technology would be the most used. It also uses 

DSRC for V2V and V2I communications.

• DSRC. The third protocol would use no cellular technology, and uses DSRC for V2V 

communications and for OBE to SCMS communications through RSE.

BAH concluded that both the cellular and hybrid protocols, the latter of which included 

cellular as an option, would not meet the recommend security level for the purposes of the study.

Additionally, it was determined that any estimated costs to bring these two options to the 

required security requirements were not considered. More discussion on the estimated costs for 

the three network protocols is addressed later in this section.

3. System requirements/network options

This section will discuss in more detail the technology considered and the requirements 

that BAH assumed the system must meet. As previously mentioned, the BAH research 

considered three protocols for the CDDS. While the cellular and hybrid protocols were deemed 

not to meet the security requirements necessary for the system, this section will still discuss 

cellular, Wi-Fi, satellite, and DSRC technologies.

DSRC is a technology that provides local, low latency network connectivity. It allows 

nearly instant network connections and broadcast messaging that requires no network 

connection. BAH stated in its report that DSRC cannot support a full CRL update (assuming a 

large fleet of vehicles with a misbehavior rate of 0.1 percent) if the vehicle passes an RSE at 

more than a few miles per hour. In order for a vehicle to receive a full CRL update, it must 

therefore pass by more than one RSE per day, and any update process would have to support 

incremental updates. BAH suggested that a typical system would require 40 seconds to complete 

a full CRL update, and a vehicle would only be in the footprint for 14 seconds in the absence of 

congestion. However, the DSRC technology would be able to support incremental updates.

Of course, any DSRC protocol requires RSE to connect to. In order to determine how 

many RSE would appear to be optimal for DSRC communications, BAH considered three types 

of deployment options for “CRL” and “no CRL” scenarios. Deployment of RSEs was considered 

on three different types of roads: secondary roads, interstate highways, and National Highway 

System roads. Each type is defined by BAH as the following:337 Secondary roads refer to 

collector roads, State highways, and county highways that connect smaller towns, subdivisions, 

and neighborhoods. Interstate highways are the network of freeways that make up Dwight D. 

Eisenhower National System of Interstate and Defense Highways. The NHS roads are the 

collection of interstate highways, principal arteries, strategic highways, major network 

connectors, and intermodal connectors. The usage of NHS roads (with 19,749 sites) was deemed 

 

337BAH CDDS Final Report, at 27. See Docket No. NHTSA-2014-0022.
243

the most logical because it achieves greater coverage than the interstate option (with 8,880 sites) 

while also requiring fewer RSE than secondary roads (with 149,434 sites) to achieve the same 

coverage, as shown below in Figure XI-1.

Figure XI-1 Coverage of RSE by Road Type

BAH used spatial optimization and information from the 2009 National Household 

Transportation Survey (NHTS) to estimate the required number of RSE to achieve the desired 

amount of coverage. As shown, NHS roads are the most realistic scenario, though secondary 

roads could achieve more coverage given more resources. Ultimately, the NHS road deployment 

method was deemed to be the most realistic.

Cellular technology was also considered for the CDDS system. Cellular systems are very 

common throughout the nation and are continuing to expand. In particular, the advancement of 

LTE (long-term evolution) technology is helping to deliver larger amounts of data to cellular 

users more quickly. However, BAH stated that this is less effective when a user is moving, and 

that the data rate for LTE is often much lower than what is theoretically possible. Although LTE 

would be able to support the full download of CRL due to the expansiveness of cellular 

networks, there are areas where cellular networks are not available, and coverage can experience 

dead spots at times. Another issue that may arise is the fact that any LTE system may suffer from 

capacity issues in any area that has many LTE users. Though cellular could potentially be a 

viable option for coverage, the BAH research concluded that cost and security issues make it an 

unrealistic option for the CDDS.
244

Wi-Fi technology supports wireless connectivity and generally higher data rates. The 

main drawback of Wi-Fi is its design for stationary terminals. Though Wi-Fi offers higher data 

rates than other options, it does not work nearly as well with moving terminals. In addition, any 

vehicle that enters the Wi-Fi hotspot must give its MAC (media access control) address and 

obtain the MAC address of all other vehicles in the hotspot before it can send communications. 

Though it uses the same basic radio system as DSRC, DSRC eliminates the need for users to 

gather MAC addresses before communication. In general, this means that Wi-Fi cannot support 

data exchanges with vehicles moving at road speeds. The costs and security risks associated with 

cellular also apply to Wi-Fi.

Satellite radio, or Satellite Digital Audio Radio Service (SDARS), uses satellites to 

provide digital data broadcast service. SiriusXM claims the following coverage capability.

338

• 3,717,792 mi2 (9,629,044 km2

) of “seamless” nationwide coverage (approximately 

98% of the U. S. land mass)

• 200 miles (322 km) off-shore coverage

• Comparison with terrestrial radio coverage of 50-100 miles (80-160 km)

However, BAH suggested that SDARS could not support the download of a full CRL 

because the download time would be longer than the average trip. If an incremental system is 

used, however, it could support updates. The costs and security risks associated with cellular also 

apply to satellite.

BAH considered misbehavior rates at three levels: 1 percent, 0.5 percent, and 0.1 percent. 

There is no way to accurately predict the misbehavior rate. The capabilities of the system to 

deliver the required amount of data to vehicles on a daily basis can be influenced by a change in 

the misbehavior rate and its influence on the size of the CRL. In a heavy data-requirement 

scenario (1 percent annual revocation rate, 3 year certificate lifetime, CRL updated daily), the 

BAH analysis estimated that the system would need to be able to deliver 150 MB of data to each 

vehicle every day. This could lead to a significant difference in costs if using commercial 

services such as cellular instead of DSRC. Because of the potential of significant cost increases 

due to data volume, BAH considered three ways to reduce CRL distribution communication 

load.

1. Balance certificate lifetime with CRL size. When certificates expire, there is no need 

for them to be retained on the CRL. As a result, reducing the lifespan of certificates 

would also reduce the size of the CRL.

 

338 SiriusXM Web site. See www.siriusxm.com/whatissiriusxm (last accessed Jan. 29, 2014).
245

2. Eliminate redundancy in the distributed CRL. If a vehicle can observe and report its 

own misbehavior, it would be able to stop transmitting messages and would be 

ignored by other vehicles without needing to check the CRL.

3. Incremental CRL updates. Theoretically, a vehicle would only need to download the 

changes to the CRL since its last update, rather than the entire CRL each time. A 

vehicle driven every day would only have to receive a single day’s worth of updates. 

However, if a car has not been driven in a longer period of time, the update will be 

larger, and will be susceptible to receiving bad messages until it is fully updated, 

though the small size of the updates would likely mean that these vehicles could be 

updated quickly.

a) Transmission method

There are many communication systems that could be used to update the on-board 

equipment on a vehicle. This includes using DSRC, Wi-Fi, satellite, and cellular. Each one 

requires its own special antennae on the OBE in order to work.

By using the RSE, small base stations could be set up that would allow the vehicles to 

“phone home” using DSRC, but in order to make sure that the V2V system can constantly be 

listening for safety component update related communications, a separate DSRC antenna will be 

used exclusively for communicating updates. We also assume a separate DSRC and antennae 

will be used for communication when vehicle talk to other vehicles and send the basic safety 

message. 

An alternative would be to install a Wi-Fi, cell, or satellite receiver that does the 

communication part of the work. In this case, the major factors that affect the cost are the capital

needed up front to install the RSE, and the continuing fixed costs to make sure that they are 

running correctly.

b) Cost model

The cost model has to take into account a lot of choices based on preliminary information 

on how the V2V equipment can update itself, what needs to be updated, and how often it needs 

to update itself. BAH has developed a cost model that relies on a set of assumptions to estimate 

costs for 40 years. Unless otherwise stated, all cost calculations have been made with the 

assumptions from Table XI-17.
246

Table XI-17 Cost Assumptions

Component Current Assumption Choice

OBE Deployment Scenario Technology Sales Scenario 1

Discount Rate 0%

Certificate Option Option 2

Certificate Phase-In Period 3 years

CRL Type Full CRL

Misbehavior Rate 0.10%

Cellular Data Price $4.00/GB

Cellular Component Cost on 

the Vehicle

$10.00

Fraction of Data Shifted from 

Cellular in Hybrid

67%

RSE Phase-In Period (Years) 15 years

# Nationwide RSEs 19,750

RSE Replacement Cost $22,719

RSE Life 15 years

Below, the preliminary costs of each protocol are broken down. For cellular and hybrid

we include the cost of OBE to allow the system to receive and transmit either through cellular or 

Wi-Fi. For the DSRC option the cost of OBE (DSRC) has already been accounted for in a 

previous cost section.

The costs of an OBE for cellular are estimated at $10, the cost for Wi-Fi is estimated at 

$2 per vehicle, and the OBE costs for a satellite system are estimated at $20. The total OBE costs 

for cellular are $10 per vehicle, and for hybrid are $12 to cover both cellular and Wi-Fi.

Table XI-18 OBE Subcomponent Cost Estimate

Included in:

OBE 

Subcomponents

Cost Cellular Hybrid DSRC

Cellular $10 1 1

Wi-Fi $2 1

Satellite $20 0 0 0

Total Cost $10.00 $12.00 $0.00
247

c) Cellular

Using cellular technology for the CDDS yields two primary cost drivers. The first is an 

estimated $10 per vehicle for cellular capability to be added to new vehicles and the second is 

the communication cost for cellular data. At $4.00/gigabyte,

339 data prices for cellular based

system such as the CDDS end up being very high. Table XI-19 below shows total estimated 

costs for using a cellular protocol.

Table XI-19 Total Estimated Costs - Cellular

Cellular

Costs

Year 1 Year 10 Year 20 Year 30 Year 40

RSE $0 $0 $0 $0 $0

OBE $171,592,000 $214,975,560 $250,550,574 $263,808,243 $269,308,171

Cellular Data $0 $444,704,378 $1,088,849,075 $1,398,075,958 $1,607,213,512

Satellite $0 $0 $0 $0 $0

Total $171,592,000 $659,679,938 $1,339,399,649 $1,661,884,202 $1,876,521,682

d) Hybrid

The hybrid protocol uses both cellular technology and opportunistic use of Wi-Fi

networks. The estimated data costs using this protocol are lower for cellular, but total estimated 

costs still remain high, as shown in Table XI-20.

Table XI-20 Total Estimated Costs - Hybrid

Hybrid Costs Year 1 Year 10 Year 20 Year 30 Year 40

RSE $0 $0 $0 $0 $0

OBE $205,910,400 $257,970,671 $300,660,689 $316,569,892 $323,169,805

Cellular Data $0 $148,234,793 $362,949,692 $466,025,319 $535,737,837

Satellite $0 $0 $0 $0 $0

Total $205,910,400 $406,205,464 $663,610,380 $782,595,212 $858,907,642

As indicated in the table, the estimated cellular communication costs are lower for this 

protocol than a pure cellular protocol, but the OBE costs are higher due to the increased per-OBE 

cost which would need to contain Wi-Fi capability. For the cellular approach, each OBE is 

estimated to cost $10, but in the hybrid approach, each OBE is estimated at $12. The hybrid

approach offers an interesting alternative to the pure cellular approach, but total costs remain 

high. As a result, it is a less attractive option than DSRC.

 

339 BAH CDDS Final Report, Table 37 at 86 at Docket No. NHTSA-2014-0022
248

e) DSRC

DSRC communications are allowed by the installation of RSEs on highways. The DSRC 

protocol option has total estimated costs that are much lower than the other two protocol designs, 

as shown in Table XI-21.

Table XI-21 Total Estimated Costs – DSRC

DSRC Costs Year 1 Year 10 Year 20 Year 30 Year 40

RSE $0 $135,137,904 $177,681,184 $177,681,184 $177,681,184

OBE $0 $0 $0 $0 $0

Cellular Data $0 $0 $0 $0 $0

Satellite $0 $0 $0 $0 $0

Total $0 $135,137,904 $177,681,184 $177,681,184 $177,681,184

The only cost driver for using the DSRC protocol is the installation of RSEs on 

highways. There is no usage of cellular, Wi-Fi, or satellite data, and as a result costs are much 

lower. RSE costs are broken down below in Table XI-22. There are three costs relating to RSEs. 

The initial installation cost is estimated at $8,839 per site. It is assumed that each site would have 

to be replaced 15 years later, and there is an annual recurring maintenance cost of $7,482 per 

site.

At this point, we assumed that RSEs will get a linear phase-in over 15 years. For the first 

three years, there will be no RSE installations. We assume that the initial vehicles will be sold 

with 3 years of certificates and they will not need updates until the end of year 3. In addition, 

there will be so few vehicles on the road with DSRC that a CRL will not be particularly valuable, 

and there will be little need to communicate a CRL. The work is therefore divided into 15 parts. 

For the first three years, no RSE will be installed; during year four, 4/15ths of the RSEs will be 

installed; and 1/15 of the RSEs will be installed every year after that, until by year 15, all RSEs 

in the design will be installed. Assuming full deployment, the estimated number of necessary 

RSEs would be 19,750. That number of RSEs would be able to cover 74 percent of the nation’s 

population every day.

Table XI-22 Road Side Equipment Cost Estimates

Average Costs per RSE Cost

Average One-Time Cost $8,839

Average Regular Replacement Cost $22,719

Average Annually Recurring Cost $7,482

If we examine just the likely communication costs on a per-vehicle basis, the cellular 

communication costs grow significantly over time as the number of vehicles that must be 

communicated with grows. Costs per vehicle are shown in Table XI-23.
249

Table XI-23 Communication Data Cost Estimate per Vehicle

Cellular Data Cost per Vehicle Year 10 Year 20 Year 30 Year 40

Cellular $2.58 $4.04 $4.57 $4.90

Hybrid $0.86 $1.35 $1.52 $1.63

DSRC $0.00 $0.00 $0.00 $0.00

The RSE per vehicle costs in each technology sales scenario were calculated in Table 

XIII-1 in Appendix A. It is assumed that these costs would be paid for at the time the vehicle is 

purchased or at the time the aftermarket equipment was purchased. Because 4/15ths of the RSEs

are assumed to be installed in year 4 and RSEs would be replaced every 15 years, the 

replacement costs are higher in year 19 and year 34. Total costs increase over time for a number 

of years because more RSEs are working and they encounter maintenance costs.

Table XI-24 provides the total preliminary costs for each communication protocol. As 

indicated in the table, the costs using the DSRC protocol are considerably lower than costs under 

the other two protocols. Furthermore, DSRC communication is believed to meet security 

requirements, thus it becomes a realistic choice for CDDS.
250

Table XI-24 Total Communication Cost Estimates per Year by Scenario

Cellular Hybrid DSRC

Year 1 $172 M $206 M $0 M

Year 2 $218 M $262 M $0 M

Year 3 $221 M $265 M $0 M

Year 4 $316 M $332 M $186 M

Year 5 $366 M $346 M $86 M

Year 6 $430 M $365 M $96 M

Year 7 $453 M $326 M $106 M

Year 8 $518 M $352 M $115 M

Year 9 $587 M $379 M $125 M

Year 10 $660 M $406 M $135 M

Year 11 $735 M $435 M $145 M

Year 12 $811 M $464 M $155 M

Year 13 $886 M $492 M $165 M

Year 14 $959 M $519 M $175 M

Year 15 $1,031 M $546 M $184 M

Year 16 $1,100 M $573 M $169 M

Year 17 $1,166 M $598 M $148 M

Year 18 $1,228 M $621 M $148 M

Year 19 $1,286 M $643 M $252 M

Year 20 $1,339 M $664 M $178 M

Year 21 $1,390 M $683 M $178 M

Year 22 $1,439 M $703 M $178 M

Year 23 $1,468 M $708 M $178 M

Year 24 $1,502 M $721 M $178 M

Year 25 $1,533 M $732 M $178 M

Year 26 $1,561 M $744 M $178 M

Year 27 $1,586 M $753 M $178 M

Year 28 $1,612 M $763 M $178 M

Year 29 $1,638 M $773 M $178 M

Year 30 $1,662 M $783 M $178 M

Year 31 $1,684 M $791 M $163 M

Year 32 $1,702 M $798 M $148 M

Year 33 $1,718 M $803 M $148 M

Year 34 $1,734 M $809 M $252 M

Year 35 $1,748 M $814 M $178 M

Year 36 $1,761 M $818 M $178 M

Year 37 $1,772 M $822 M $178 M

Year 38 $1,869 M $856 M $178 M

Year 39 $1,876 M $859 M $178 M

Year 40 $1,877 M $859 M $178 M
251

f) CRL type

BAH found that one input assumption was “highly uncertain and highly impactful on the 

... cost analysis.” That input is the type of Certificate Revocation List. By choosing a different 

type of CRL update to the V2V device, you can significantly change the cost to keep devices 

safely updated. The two types of CRL update that BAH considered were “Complete Daily CRL”

update and “Incremental Daily CRL” update. For the first option, Complete Daily CRL, the 

entire list is downloaded to the vehicle every day. In the Incremental Daily CRL, only the 

changes made to the list are downloaded. Thus, somewhere close to only 1/365 (0.27 percent) of 

the Complete CRL needs to be downloaded daily for the Incremental CRL update. Because the 

Complete Daily CRL downloads are always much bigger than the Incremental Daily CRL 

download, the Complete Daily option costs more than the Incremental CRL. Since the 

Incremental Daily CRL cost would be almost as low as having no CRL at all, rather than 

speculate on the small increment in cost, the cost estimates presented here include two options: 

Full CRL and No CRL, describing the extreme cases of how much the CRL will cost. These 

CRL download costs only apply to cellular and hybrid. We assume that there is no cost for 

DSRC with RSE because there are no anticipated per transmission costs associated with DSRC 

communication, as compared to the other communication mediums used in cellular and hybrid. 

Total estimated costs per year are further broken down in Table XI-25 below. There are 

no communication costs in the first three years in the DSRC with RSE option. The cellular and 

hybrid (cellular and Wi-Fi) options have costs in the first three years due to OBE costs.

Table XI-25 Total Cost Estimates Comparing Full CRL to No CRL in Millions (2012 

dollars)

Total costs Year 1 Year 10 Year 20 Year 30 Year 40

Cellular No CRL 172 M 215 M 251 M 264 M 270 M

Cellular Full CRL 172 M 660 M 1339 M 1662 M 1877 M

Hybrid No CRL 206 M 258 M 301 M 317 M 323 M

Hybrid Full CRL 206 M 406 M 664 M 783 M 859 M

DSRC With RSE No/Full CRL 0 M 135 M 178 M 178 M 178 M

4. Communication costs conclusions

Of the three scenarios considered, the DSRC with RSE ended up being the most 

economically viable as well as allowing for the most security. While cellular and hybrid show 

some merits, the costs and security concerns that they hold make them generally less attractive 

options for the CDDS. The implementation of a DSRC system, however, will take time. A 15 

year phase-in plan has been assumed to be necessary for the RSEs, but other options may be 

considered. In addition, decisions on how to implement ideas such as an incrementally updating 

CRL must be further analyzed.
252

F. Security credentials management system cost modeling

Beyond the costs of the vehicle equipment and the fuel economy impact of that 

equipment (due to increased weight), we need to account for the costs of services that support the 

V2V system for the vehicle fleet. In addition to the cost of ensuring that the different elements of 

the V2V system are able to communicate, discussed above, another such cost is for the SCMS. 

The main function of the SCMS is to ensure that the communications from vehicles to other

vehicles are authentic and can be trusted. Additional information on the SCMS is found in 

Section IX.

1. Preliminary projected costs for SCMS

In estimating the costs for the SCMS, we anticipate that a fee of approximately $3.14 per 

vehicle could support the SCMS for all three scenarios. This fee would most likely be a one-time 

fee incorporated into the purchase price of a new vehicle or aftermarket equipment. The fee 

collected from the new vehicle or aftermarket sales each year would support the operations of the 

SCMS for that year. The operation of the SCMS in the next year would be supported by the fees 

collected from the new vehicle or aftermarket sales for that year.

We arrived at the conclusion that a fee of $3.14 per new vehicle sold can support the 

SCMS by first estimating the costs of the SCMS for each year (beginning in 2020—our tentative 

first year for implementing the V2V system). This annual cost varies over time (with the first 

year being the least costly) because additional infrastructure is needed to support an increasing 

number of vehicles as V2V technology penetrates the fleet. We estimate the cost to support the 

SCMS ranges from $5 to $36 million in year 2020, whereas we estimate the cost to range from 

$23 to $93 million in year 2058. However, the currently available information indicates that the 

average annual cost for the SCMS over this span of 39 years (2020 to 2058) is $60 million. We 

anticipate that this average annual cost could be covered by a $3.14 fee collected along with the 

purchase of each new vehicle.

In order to understand the costs of the SCMS, we need to first define the components of 

the SCMS and how they interact with each other. The SCMS is made up of defined 

“components” that all have specified jobs and contribute to the operation of the SCMS function 

for V2V, including the components that make up the current system design to enable privacy 

while meeting system security needs. Details regarding the current system design and its 

components are found in Section IX.B.

a) Scenarios and assumptions used in developing preliminary projected costs

This analysis of costs is based on the latest SCMS design specifications (current as of 

January 2014) developed collaboratively with NHTSA and CAMP. These specifications 

establish parameters that the SCMS would likely need to meet in order to accomplish the 

aforementioned goals. It is important to note that these specifications are not finalized and could 
253

change. The following is a discussion of the assumptions that we are currently using for the 

purposes of estimating the potential costs of the SCMS.

(1) Technology Sales Scenario Assumptions

For the purposes of calculating the preliminary potential costs of the SCMS in this 

section, we will be using the same three technology implementation scenarios that we used to 

calculate Vehicle Equipment Costs, above. As a reminder, the three scenarios all based on a 

projected vehicle sale that starts at 17.04 million in 2020 and increase to 20.38 million in 2050. 

The sales stay flat at the 2050 level afterwards. These scenarios are briefly summarized as 

follows.

• Scenario 1: OBE on new vehicles with 35 percent-70 percent-100 percent phase-in 

starting in MY2020 with aftermarket devices

• Scenario 2: slower OBE implementation than that specified in Scenario 1, no aftermarket

• Scenario 3: the slowest OBE implementation among the three scenario and the rate would 

not reach the 100 percent level as did other two scenarios, no aftermarket

(2) Certificate issuance assumptions

For this analysis, we are assuming that a new vehicle will receive a three-year batch of 

reusable, overlapping five-minute certificates valid for one week.340 The term “overlapping” in 

this context refers to the fact that any certificate can be used at any time during the validity 

period.341 Key implications of this design are as follows:

• Certificates do not expire unless they are used, or the week ends. They are not time 

sensitive.

• Depending on the number of certificates designated for one week, they will be reused an 

uncertain number of times with no predetermined order.

• The certificate batch size may be 3,000, which is based on a set of approximately 20 

certificates being used per week. Thus, the 3,000 certificate batch size would cover three 

years’ of use before requiring certificate updates.

• There may be some discretion about how many certificates will be designated for a oneweek period. This would be based on the choice of the user, OEMs, or SCMS 

owners/operators. However, the current assumption is 20 certificates per week.342

 

340 Security Credentials Management System (SCMS) Design and Analysis for the Connected Vehicle System 

(Booz Allen Hamilton, Inc., Dec. 2013, at 14). See Docket No. NHTSA-2014-0022 341 Id. 342 Id.
254

Afterwards, each vehicle will receive updates with two years of certificates at two year 

intervals.

We note that the variable that can cause the largest changes in overall cost is the 

frequency of certificate downloads. The final decision on this variable has not been made, and 

costs could change in the future based in large part on this variable.

(3) Hardware/software assumptions

Another important cost driver is the fact that hardware and software need to be refreshed 

every five years in order to keep the SCMS function equipped with the latest security 

capabilities. This assumption has been included in the cost estimates, which show an increase in 

costs every five years.343

(4) Location assumption

The estimates are based on Richland, WA, as the baseline for all functions, in order to be 

consistent with the BAH cost model.344 BAH identified cost factors for Richland, WA, as well as 

Denver, CO; Chicago, IL; San Antonio, TX; Washington, DC; and Gastonia, NC. Richland was 

chosen as a baseline given the spread of costs for the area and used to produce an initial

calculation of cost for the purpose of the SCMS cost analysis.

b) Annual total preliminary cost for the SCMS

In order to estimate the cost per new vehicle sold, we first need to estimate the cost of the 

entire SCMS. This cost is different for each year because the number of vehicles operating with 

V2V capabilities will increase over time. When the number of these vehicles increases, the 

SCMS will need to support the functions of the additional vehicles with an increased capacity to 

be able to generate and issue security certificates. Table XI-26, below, shows the likely cost 

needed to support each SCMS function. Each column (labeled 0, 10, 20, 30, 40) show the costs 

for the SCMS function in that year. For example, the PCA will cost $5,541,402 in Year 0 to 

operate. However, that same function will cost $7,196,135 to operate in Year 10. The last row in 

Table XI-26 shows the total cost of the entire SCMS in each of those years. All of these costs are 

undiscounted. The costs in Table XI-26 also assume that vehicles are being sold at the rate 

described in “Technology Sales Scenario 1.” In other words, we are assuming an increasing sales 

volume (beginning at 17 million in 2020, and rising to approximately 20 million thereafter 

starting in 2050).

 

343 Id., at 106. 344 Id.
255

Table XI-26 Undiscounted Cost Estimates per Component for Selected Years, Scenario 1, 

Two Year Downloads

Component Year

0 10 20 30 40

PCA $5,541,402 $7,196,135 $11,948,687 $16,281,686 $20,257,673

RA $6,671,907 $7,755,342 $13,636,463 $19,206,293 $24,471,619

LA $4,918,141 $5,644,934 $9,964,652 $14,117,090 $18,048,462

MA $3,546,999 $3,757,398 $5,514,098 $7,256,497 $8,815,887

LOP $1,320,948 $1,829,286 $3,434,603 $5,201,161 $6,214,164

ECA $4,079,230 $4,167,392 $4,167,392 $4,167,392 $4,167,392

Intermediate CA $4,184,493 $4,024,319 $7,940,176 $11,856,033 $15,689,120

Root CA $1,609,923 $1,592,732 $1,592,732 $1,592,732 $1,592,732

DCM $4,061,098 $4,507,122 $4,507,122 $4,507,122 $4,507,122

SCMS Manager $323,330 $679,564 $679,564 $679,564 $679,564

Total Cost $36,257,471 $41,154,224 $63,385,488 $84,865,570 $104,443,733

The preliminary costs are generally driven by new hardware, software, facilities, and full 

time equivalent positions (FTEs). However, the costs do not rise in a linear fashion because new 

hardware and software is necessary at regular intervals (i.e., every 4 to 5 years). Thus, the costs 

in the first year and in every fifth year are noticeably higher in the estimates than in other years 

as a result. In these years, the total costs increase by a fairly significant margin but then decrease

again in the next year. However, when we average the costs of the entire SCMS over this 40-year 

period, the estimated annual cost based on preliminary information for the SCMS is $59 million.

We note that the cost estimates above are subject to change given the uncertainty 

surrounding the functions of various aspects of the SCMS. The most notable uncertainty is the 

Misbehavior Authority (MA). As described above, this function is responsible for detecting 

misbehavior (i.e., systems that are not broadcasting accurate information) and publishing CRLs 

to notify other participants in the V2V environment that they should not trust the information 

from those sources. At this point, it is unclear how the SCMS will perform this function. Thus, it 

is unclear whether the cost estimates for this function are accurate. At the moment, we have 

based it on estimations of hardware, software, facilities, and employee needs according to current 

specifications. We intend to update our cost estimates for this function (as well as others) as the 

details of those functions become more definite in the future.

c) Cost methodology for component functions of the SCMS

In order to arrive at the annual and total preliminary cost estimates for the entire SCMS, 

we had to examine the costs for each component function of the SCMS. While this report does 

not present the calculations for each component function, we have selected an illustrative 
256

example to communicate the methodology that we used to arrive at the estimates for each 

component. Table XI-27 below shows the annual cost for the Pseudonym Certificate Authority 

(PCA) function in each of five different years (2020, 2030, 2040, 2050, and 2060). Table XI-27

also shows the different types of expenditures needed to support the PCA and how each is 

anticipated to change over time.

Table XI-27 Undiscounted Cost Estimate of PCA for Selected Years, Scenario 1, Two Year 

Downloads

PCA Year

Cost Category 0 10 20 30 40

Hardware Purchase $615,472 $1,500,762 $1,968,620 $2,141,499 $2,203,241

Hardware, O&M $0 $107,850 $179,301 $206,833 $220,324

Software Purchase $2,311 $7,801 $10,729 $12,642 $12,854

Software, O&M $0 $905 $1,585 $1,993 $2,314

Facilities: Initial Cost $1,037,695 $1,620,582 $1,894,360 $2,115,775 $2,115,775

Facilities: Annual $0 $72,310 $122,241 $145,169 $159,464

FTEs: Total Costs $3,885,925 $3,885,925 $7,771,850 $11,657,775 $15,543,700

Total Cost $5,541,402 $7,196,135 $11,948,687 $16,281,686 $20,257,673

2. Funding the SCMS

For such a system, there must be a cost to the user. In the case of the SCMS function, we 

assume that the user will have to pay a cost for their use of the SCMS system upfront, when a 

new vehicle is purchased (i.e., the cost of the SCMS becomes part of the new vehicle purchase 

price). While other payment methods are possible, it seems that including the cost of the SCMS 

in the price of the new vehicle or the price of aftermarket devices is the easiest way to ensure 

payment for (and continued participation in) the system. Other payment methods (e.g., monthly 

fees) may discourage users from participating in the V2V environment. If this happens, the 

number of on-the-road vehicles that are communicating will be reduced, and the effectiveness of 

the V2V system will consequently decrease. The agency emphasizes, however, that it will 

consider this issue further going forward as new information becomes available.

G. Conclusion of preliminary V2V implementation cost estimates

When considering all four parts of this preliminary cost analysis (vehicle equipment, fuel 

economy impact, SCMS, and communications costs), we estimate that the total costs to the 

consumer for each new vehicle will be approximately $341 - $350 (across the 3 percent to 7 

percent discount rates) in 2020. We note that over time this amount will decrease to 

approximately $209 - $235 in 2058 (when considering the discount rates and the three sales 

scenarios), due in large part to cost reductions that manufacturers will realize as they gain more 

experience manufacturing V2V vehicle equipment (learning). We note the total costs will 

decrease over time even though certain costs will increase over time. While the SCMS costs will 

increase over time due to the need to support an increasing number of vehicles, these costs are 
257

small in comparison to the vehicle equipment costs. Thus, the effect of manufacturer learning in 

reducing the costs over time substantially outweighs cost increases such as the SCMS.

Preliminary costs are summarized mainly on a model year basis. For new vehicle sales, 

costs for the V2V system occur when the vehicle is sold. For fuel economy impacts, costs are 

discounted back to present value - when the vehicle is sold. For SCMS and communication costs, 

costs are assumed to be charged when the vehicle is sold to cover these costs that would occur in 

the same calendar year as the model year when it is sold. Thus, the assumption is that at the time 

the vehicle is sold, the price of the vehicle is increased to pay for what is needed in that year. The 

estimated costs per vehicle for the SCMS (ranging from $1 to $6 per vehicle) and 

communications (ranging from $3 to $13 per vehicle) are relatively low.

For aftermarket sales, costs occur when the aftermarket equipment is sold, which is not 

the same as the model year of the vehicle for which it has been purchased. Thus, the calendar 

year of the assumed sale is when aftermarket costs are added to the model year sales to get total 

costs for the model year. Here again, costs for SCMS and communication could be charged at the 

point of sale.

Because of the large number of variables affecting the costs of the V2V system, the 

preliminary total annual costs of the system fluctuates substantially from year to year. The total 

costs for new vehicles (over three sales scenarios and two discount rates) rise from $0.3 to $2.1 

billion dollars in 2020 to $1.1 to $6.4 billion in 2022, before decreasing slowly to a relatively 

stable level of $1.1 to $4.6 billion.

To put the costs into perspective, we compared the passenger car costs over time in the 

four cost categories, using the 3 percent discount rate. The OEM costs are 95 percent of total 

costs initially, then decreasing slowly to 88 percent of total costs as the learning curve takes 

effect and other costs increase. The fuel costs (at around 5 percent) are typically higher than the 

communication costs (at around 4 percent) and the SCMS cost stay in the 1 to 2 percent range 

over the years.

H. Economic practicability

Under the Safety Act, standards set by NHTSA must be practicable. One criteria of a 

practicable standard is that it is economically feasible (i.e., compliance with the standard is not 

so burdensome [costly] so as to create a significant harm to a well-established industry). If a 

standard is deemed to be economically infeasible, it can be considered impracticable by a court. 

Therefore, the economic feasibility of V2V will need to be considered when deciding whether to 

mandate V2V. Our analysis is based on the information on potential costs for a V2V system that 

has been collected so far by the agency, even while recognizing that the information is 

preliminary and that additional information will come to light as the agency moves forward.
258

Although no V2V system currently exits other than in prototype form, we have attempted 

to make a preliminary estimate of costs to implement such a system based on available 

prototypes and projections about system deployment. Based on those costs, it appears likely that 

any standards to require elements of the V2V system will be economically practicable. We 

emphasize that these estimates are subject to substantial amendment as more information is 

acquired and any plan for implementation gains greater clarity. NHTSA and DOT will be 

constantly attentive to options that may reduce these costs. More important, these projected costs 

are best thought of as the price for a new and important element of the nation’s transportation 

infrastructure and should be considered jointly with the safety and other benefits the system 

would bring as discussed in the next section.
259

XII. Preliminary Effectiveness and Benefits Estimates of V2V 

A. Analysis of preliminary benefits of V2V technology

The agency estimates the system crash avoidance and crashworthiness effectiveness by 

comparing crash rates and the injury probabilities of vehicles with and without V2V technology. 

The agency focused its evaluation on IMA and LTA, the two applications currently considered to 

be exclusively enabled by V2V technology. To correspond with the cost estimates, benefits were 

also estimated for the three technology implementation scenarios described in the cost section.

Based on the estimation methodologies described in this section, the agency estimates 

that IMA would help drivers avoid 41 to 55 percent of target intersection crashes345 and reduce 

the severity of intersection crashes by an average of 1.17 mph delta-V.

The agency estimates that LTA would prevent 36 to 62 percent of left turn crashes. LTA 

is considered to have no impact on mitigating the severity of the left turn crashes that cannot be 

avoided. Therefore, the crashworthiness effectiveness for LTA is assumed to be zero in this 

analysis.

We therefore estimate that IMA and LTA together would prevent a maximum of 413,000 

to 592,000 crashes, save 777 to 1,083 lives, and reduce 191,000 to 270,000 MAIS injuries under 

the fast technology implementation plan specified in Scenario 1.

Under Scenario 2, a slower implementation pace than Scenario 1, IMA and LTA would 

also accrue the maximum benefits as in Scenario 1. The primary difference between these two 

scenarios is that Scenario 1 would achieve other levels of benefits (e.g., 70 or 90 percent of the 

maximum benefit) 2 to 3 years earlier than would Scenario 2. 

Under Scenario 3, the slowest implementation pace among the three, which only reaches 

25 percent of the full implementation level, IMA and LTA would accrue at most 6 percent of the 

maximum benefits achieved by Scenarios 1 and 2. The disparity in benefits demonstrates that in 

order to realize the full potential of V2V technology, achieving full implementation over time is 

critical.

1. Analysis overview

Preliminary cost and benefit estimates vary with the V2V safety device implementation 

strategy. As stated in the cost section, the agency used three scenarios to examine the variation of 

 

345 The result of adding 15 – 24 percent for PCP-S and 26 - 31 percent for PCP-M.
260

the cost and benefit estimates and to understand the impact of various technology 

implementation schedules on the costs and benefits. The first scenario represents the most

aggressive V2V implementation scenario among the three, while the third one represents the 

slowest and lowest implementation schedule among the three. The detailed description of these 

implementation scenarios are provided above in Section XI.

As stated earlier, the preliminary benefit estimates are for IMA and LTA only. The 

agency intends to examine the benefits of other safety applications -- FCW, BSW/LCW, and 

DNPW – when sufficient data are available to estimate their effectiveness.

The preliminary benefit estimates presented in this report include (1) the maximum 

undiscounted annual benefits (in terms of fatalities and injuries reduced and crashes avoided) 

when all passenger vehicles can communicate with each other, and (2) the undiscounted annual 

benefits for calendar years 2020 to 2058.

The benefits of a V2V safety application depend upon three primary components:

• The target population that would be impacted by the application, 

• The system effectiveness of the application in preventing the crash (crash 

avoidance) and/or mitigating the severity of the crash (crashworthiness), and 

• The probability that involved vehicles can communicate with each other

(communication probability).

Of these three components, communication probability would vary with the number of 

V2V-equipped vehicles entering into the market each year. Therefore, at a given year i of a V2V 

implementation, the benefits of an application can be noted as:

Equation XII-1 Benefits Estimation Calculation

Bi = TP * Ea * Ci + TP * (1 – Ea) * Ew *Ci

Where, Bi = the benefit for year i

TP = the target population

Ea = the crash avoidance effectiveness of an application

Ew = the crashworthiness effectiveness of an application

Ci = the communication rate.

The target population (TP) includes crashes, fatalities, injuries, and property damaged 

only vehicles (PDOV, vehicles that only incur property damage and none of their occupants 

incur an injury). Effectiveness (Ea and Ew) of a safety system is derived by comparing crash rates 
261

and injury rates for vehicle with and without the system. The effectiveness can be represented by 

the generalized formula:

Equation XII-2 Effectiveness Calculation

Where, Pwith = crash rate (or injury rate for crashworthiness) for vehicle with the 

system

Pwithout = crash rate (or injury rate for crashworthiness) for vehicles without the 

system.

For crash avoidance, the effectiveness (Ea) takes into account both the reduction in 

exposure to conflict and the probability of a crash when a conflict occurs.

The communication rate (Ci) is the probability that two passenger vehicles can 

communicate with each other, which means that it depends on the number of vehicles that have

V2V, and is consequently different depending on the technology implementation scenarios.

Besides Ci, the benefit process represented by Equation XII-1 is identical for all implementation 

scenarios; meaning the other variables in the equation remain the same (e.g., the target 

population). The next sections discuss in greater detail the implementation scenarios and the 

three primary factors in determining benefits: target population, and effectiveness, and 

communication rates.

2. Technology implementation scenarios

Restated here for convenience, following is a basic summary of the three potential 

technology deployment scenarios used for the cost and benefits analysis in this report. Additional 

information on these scenarios is found in Section XI.C.3.a). As previously noted, the dates 

selected here are simply assumptions made for the convenience of this analysis, and reflect no 

judgment by the agency on timing or phase-in requirements.

a) Scenario 1

• 35 percent-70 percent-100 percent vehicle equipment phase-in starting in MY2020

• 100 percent installation of two safety applications for those with vehicle equipment 

• Aftermarket deployment for MY2015-2021 vehicles (applicable vehicles)

o Starting 2022 and continuing for a total of 5 years 

o 5 percent of applicable vehicles for 2022 and 2023

 For example, for year 2022, applicable old vehicles include the survived 

MY2015-2019 vehicles, 65 percent of the survived MY2020 vehicles, and 30 

percent of the survived MY2021 vehicles. Five percent of these vehicles 

would be equipped with an aftermarket device.
262

 For year 2023, the applicable old vehicles include 95 percent of those 

applicable old vehicles that were defined for year 2022 and would survive in 

year 2023.

o 10 percent of applicable vehicles for 2024-2026

o The estimated number of aftermarket sales for the 5 implementation years in this 

scenario are: 

 4.70 million in MY2022

 4.37 million in MY2023

 8.09 million in MY2024

 7.06 million in MY2025

 6.11 million in MY2026

• ASD and VAD are assumed to have an equal penetration rate each year. 

b) Scenario 2 

• 35 percent-70 percent-100 percent vehicle equipment phase-in starting in MY2020

• 50 percent installation of two safety applications for MY2020-2022 vehicles that have 

vehicle equipment, 60 percent for MY2023, 70 percent for MY2024, 80 percent for 

MY2025, 90 percent for MY2026, 100 percent for MY2027 and later. 

• No Aftermarket deployment

c) Scenario 3 

• 5 percent vehicle equipment for MY2020, 15 percent for MY2021, 25 percent for 

MY2022 and newer vehicles 

• 100 percent installation of two safety applications for those vehicles that have vehicle 

equipment

• No Aftermarket deployment

3. Target population for V2V technology

The target population includes crashes, fatalities, injuries, and property-damage-only 

vehicles (PDOV) that are vehicles that only incur property damage and none of their occupants 

incur an injury. Although the preliminary benefit estimate is only for the IMA and LTA safety 

applications, the target population for FCW and LCW and for heavy vehicles is also provided 

here to offer a comprehensive illustration of the potential safety impact that could result from the 

V2V-based safety applications.
263

Overall, the agency used an average of 2010 and 2011 CDS and FARS data to determine 

that there are approximately 5.37 million police-reported crashes annually in the United States346

involving approximately 32,683 fatalities and 4.29 million MAIS347,348 1-5 injuries. Of these 

crashes, 3.34 million crashes involving two or three passenger vehicles349 would be impacted by 

the V2V-based safety applications. These crashes account for 62.3 percent of the total crashes.

Crashes not included in the 3.34 million are (a) 1.5 million single-vehicle crashes and 

230,000 crashes that involved motorcycles, since these crashes are not expected to be benefited 

by V2V-based safety applications, (b) about 60,000 crashes where four or more vehicles were 

involved as they could involve more complicated and less clear interactions between vehicles 

and require further evaluation, and (3) about 240,000 crashes where heavy vehicles

350 were 

involved, because the agency is only evaluating passenger vehicle351 crashes at this time and 

plans to address crashes involving heavy vehicles in a later decision. However, the V2V-based

applications would affect 3.59 million crashes (66.9% of the total crashes) if heavy-vehicle 

crashes were included.

352

To identify the target crash population for a specific V2V-based application, the agency 

starts with the 37 pre-crash scenarios as described in Section III.A. The target population for an 

application is categorized into major scenarios where the application might perform differently. 

The following describes the major scenarios for intersection crashes (affected by IMA and LTA), 

rear-end crashes (FCW), and lane change/merge crashes (BSW/LCW).

• Intersection crashes for IMA and LTA

o turn-into path into same direction or opposite direction (i.e., “turn-into path, 

initial opposite direction” crashes are crashes where one involved vehicle is 

making a left turn at the intersection and the other vehicle is traveling straight 

through the intersection from the opposite direction)

 

346 Based on 2010-2011 NASS-GES and FARS data. 347 MAIS (Maximum Abbreviated Injury Scale) represents the maximum injury severity of an occupant at an 

Abbreviated Injury Scale (AIS) level. AIS ranks individual injuries by body region on a scale of 1 to 6: 1=minor, 

2=moderate, 3=serious, 4=severe, 5=critical, and 6=maximum (untreatable).

348 GES and FARS only record the police-reported crash severity scale known as KABCO: K = fatal injury, A = 

incapacitating injury, B = non-incapacitating injury, C = possible injury, O = no injury. These KABCO injuries the n 

were converted to MAIS scale through a KABCO-MAIS translator. The KABCO-MAIS translator was established 

using 1982-1986 NASS (old NASS) and 2000-2007 Crashworthiness Data System (CDS). Old NASS and CDS 

recorded both KABCO and MAIS scales thus enabling us to create the KABCO-translator. 349 Passenger-vehicle-to-passenger-vehicle and passenger-vehicle-to-heavy-vehicle account for 4.5 percent 

(241,000). 350 Heavy vehicles include trucks and buses with GVWR greater than 10,000 pounds. 351 Passenger vehicles include passenger cars, vans, minivans, sport utility vehicles, and light pickup trucks with 

gross vehicle weight rating (GVWR) 10,000 pounds or less. 352 Passenger-vehicle-to-passenger-vehicle and passenger-vehicle-to-heavy-vehicle account for 4.5 percent 

(241,000).
264

o straight cross passing

• Rear-end crashes for FCW

o Lead vehicle stopped (LVS) 

o Lead vehicle moving at a slower speed or was accelerating (LVM) 

o Lead vehicle decelerating (LVD) 

• Lane change/merge crashes for BSW/LCW have been defined as crashes where a 

vehicle made a lane changing/merging maneuver prior to the crash

Note that “intersection” in this analysis included intersection, intersection-related, 

driveway/alley, and driveway access areas. Rear-end crashes does not include crashes where the 

lead vehicle made a lane change/merge pre-crash maneuver. Furthermore, crashes involving 

alcohol, vehicle failure, and loss-of-control are also excluded, because we assumed that V2Vbased safety applications would not produce an effective response by the driver under these 

conditions.353 For the preliminary benefit analysis, the agency focused only on IMA and LTA.

FCW was not included in the benefits estimation because of the significant overlap with radarbased FCW systems; BSW/LCW and DNPW were also not included because insufficient data 

exists at this time to assess their effectiveness.

Table XII-1 shows crash statistics for the four safety applications. As shown, annually

there are 2.94 million crashes with 2,669 fatalities and 1.07 million MAIS 1-5 injuries that could 

be addressed by these four V2V safety applications. In addition, about 4.05 million PDOV 

crashes could also be addressed. Of these, 1.04 million crashes, 1,932 fatalities, 450,000 MAIS 

1-5 injuries, and 1.28 million PDOVs could be impacted by IMA and LTA. Separately, IMA 

could impact 760,000intersection crashes and thus the 1,637 associated fatalities and 

300,000MAIS 1-5 injuries. LTA could impact 280,000 crashes and the associated 295 fatalities 

and 150,000 MAIS 1-5 injuries. 

 

353 Crash scenarios were excluded based on the criteria that an impaired driver would be required to react, and the 

fact of their impairment would likely lead them not to react as required.
265

Table XII-1 Safety Target Population for FCW, LCW, IMA, and LTA - Passenger 

Vehicles354

FCW 

(LVS)

FCW 

(LVM

)

FCW 

(LVD)

FCW 

TOTAL

IMA LTA IMA, & 

LTA 

TOTAL

LCW GRAND 

TOTAL

Crashes 946,668 167,807 329,510 1,443,985 757,195 283,503 1,040,698 458,506 2,943,189

PDOC355 641,153 113,407 225,797 980,357 472,694 150,530 623,224 362,688 1,966,269

Injury 305,515 54,400 103,713 463,628 284,501 132,973 417,474 95,818 976,920

Fatality 161 234 47 442 1,637 295 1,932 295 2,669

MAIS 1-5 

Injuries

342,516 63,350 117,425 523,291 303,987 150,674 454,661 94,430 1,072,382

PDOVs[1] 

in PDOC

1,321,417 233,732 465,367 2,020,516 974,223 310,242 1,284,465 747,500 4,052,481

Figure XII-1 provides a graphical breakdown of crashes and the process as discussed 

previously for deriving the target population for benefits estimation. The potential target 

population as shown is where heavy vehicle crashes are considered. The graphical breakdown

begins with the total annual number of police-reported crashes of 5.37 million, and ends with the 

target crashes of 1.04 million for IMA and LTA.

 

354 Source: 2010-2011 GES and FARS. 355 Property-damage-only crash.
266

Figure XII-1 V2V Benefits Estimation Target Population (Annual) Breakdown

B. Effectiveness of the V2V safety applications

The system crash avoidance and crashworthiness effectiveness is determined by 

comparing crash rates and the injury probabilities of vehicles with and without V2V. Since V2V 

is an emerging technology and is not in production, a statistical analysis of vehicles with and 

without the technology using real-world crash data was not feasible. Instead, the agency 
267

developed a computer simulation model, Safety Impact Methodology (SIM),

356 and a laboratory 

driver simulator (MiniSim), to estimate the effectiveness and then the preliminary benefits of 

V2V-based safety application technologies, specifically, IMA and LTA.357 Therefore, these two 

sources are the basis for estimating the crash avoidance and crashworthiness values.

1. Safety Impact Methodology - SIM

In order to obtain a crash warning using V2V technology, two V2V-equipped vehicles 

need to interact during a potential crash situation – if a V2V-equipped vehicle interacts with a 

non-V2V-equipped vehicle in a potential crash situation, no warning is to be expected, because 

the non-equipped vehicle would produce no BSM for the equipped vehicle to recognize and 

respond to. To be able to estimate the effectiveness of advanced crash avoidance technology 

such as V2V, NHTSA developed a methodology that uses available data and computer 

simulation,358 extending current estimation capabilities and enabling V2V technology to be 

“exposed” to more conflict situations to make up for the lack of crashes in the real-world crash 

databases. This allows the agency to better comprehend the crash avoidance potential and the 

performance criteria of the V2V technology prior to the technology’s actual deployment.

The “Safety Impact Methodology” or “SIM” estimates safety benefits in terms of the 

number of crashes avoided using the estimated effectiveness of the safety applications to avoid 

crashes. These estimates are obtained using the following set of equations:

Equation XII-3 Number of Crashes Avoided Calculation

Number of Crashes Avoided = Number of Target Crashes × Application Effectiveness

The application effectiveness is estimated based on the following equation:

Equation XII-4 Application Effectiveness Calculation

Application Effectiveness = 1 – Exposure Ratio × Crash Prevention Ratio

 

356 Safety Impact Methodology (SIM): Application and Results of the Advanced Crash Avoidance Technologies 

(ACAT) Program (Funke, Srinivasan, Ranganathan, and Burgett, June 2011, Paper Number 11-0367, 22nd 

International Technical Conference on the Enhanced Safety of Vehicles). See wwwnrd.nhtsa.dot.gov/pdf/esv/esv22/22ESV-000367.pdf (last accessed Jan. 29, 2014). 357 The agency examined 50 intersection or left turn across path crashes from the NASS data base for which we had 

EDR information from both vehicles involved. Thus, we knew the velocity and brake activation of both vehicles 

from 5 seconds to 1 second before the crash. These analyses were used to determine that the SIM results did match 

very well with real crashes.

358 For an overview of this methodology, see supra note 354.
268

Where:

Equation XII-5 Exposure Ratio Calculation

Exposure Ratio (ER) = 

And

Equation XII-6 Crash Prevention Ratio Calculation

Crash Prevention Ratio (CPR) =

The Exposure Ratio (ER) is the measure of change a safety application may have on 

drivers being exposed to conflict.359 In other words, V2V safety applications may change driver 

behavior such that a driver can better anticipate a potential conflict and adjust such that the 

conflict does not occur. The change to drivers’ exposure to conflicts is obtained from field 

observations (not simulated in SIM) during a field operational test, usually over an extended 

period of time. However, it may be difficult to quantify the exposure to conflicts with and 

without the safety application with any statistical significance due to relatively short test time 

periods (a driver’s adaptation to a safety application usually takes longer than the 3 to 24 weeks a 

driver [subject] experiences the safety technology in the context of the current research). In 

recognition of this difficulty, a conservative estimate of the ER parameter is set to one for 

purposes of the present analysis, meaning that there is no difference in exposure to driving 

conflicts whether the V2V application is present or not.

The Crash Prevention Ratio (CPR) equation accounts for whether or not a vehicle will 

crash with another vehicle in a driving conflict as a result of the first vehicle’s crash-avoidance 

action, such as braking to stop. It is estimated using a SIM computer-based simulation. The 

SIM’s primary duty in relation to estimating the CPR is to mimic, as close to real-world as 

possible, the actual conditions, interactions, and performance of the driver, vehicle, and safety 

application of target driving conflicts corresponding to major pre-crash scenarios. This 

simulation uses input data from national crash databases; driver, vehicle, and V2V safety 

application performance data from naturalistic field operational tests (Safety Pilot Model 

Deployment); track tests; and related driver, vehicle, or safety application evaluation studies.

Outputs of the tool consist of the number of crashes avoided and impact speed reduction that can 

 

359 Driving conflicts correspond to the kinematics of the target pre-crash scenarios. An exposure to a driving conflict 

is counted when the movements of the host vehicle and the principal other vehicle match the configuration of the 

driving conflict and the two vehicles are on a crash course if a crash avoidance action is not taken by either vehicle.
269

be translated into harm reduction, including savings in crash comprehensive costs and decreases 

in the number of persons injured at different levels of the MAIS.

To support the calculation of the CPR by the SIM, the simulation component needs to 

generate data on crashes both with and without the V2V safety applications. A 2010 report by 

Ford, Volvo, and UMTRI developed an approach to generating such data by using field trials to 

create a number of driving scenarios that are relevant to the technology/safety application in 

question, but may or may not lead to a crash.360 Each scenario is evaluated without the V2V 

safety application, and then the same scenario can be evaluated again with the application in 

place. Each scenario comprises a number of “conflicts” generated using a Monte Carlo361

approach, where a conflict is a specific driving situation (e.g., vehicle traveling at 50 mph detects 

a lead vehicle that is stopped 200 feet away) that would fall under the pre-crash scenario in 

question (e.g., lead vehicle stopped). Each conflict can be evaluated for whether a crash is 

avoided or does occur. If a crash is avoided, benefits are estimated based on the number of 

fatalities and injuries that are avoided. If a crash would occur, benefits are estimated in relation 

to reductions in fatalities and injuries due to possible mitigation of crash impact. A change in 

crash impact is measured by the change in velocity, delta-V, which can be translated into 

changes in fatalities and injuries. For this exercise, a similar approach was implemented into the 

SIM. Figure XII-2 illustrates the structure of the SIM developed to estimate V2V safety 

application benefits.

 

360 Advanced Crash Avoidance Technologies (ACAT) Program – Final Report of the Volvo-Ford-UMTRI Project: 

Safety Impact Methodology for Lane Departure Warning – Method Development and Estimation of Benefits

(Gordon et al., Oct. 2010, Report No. DOT HS 811 405). See

www.nhtsa.gov/Research/Crash+Avoidance/ci.Office+of+Crash+Avoidance+Research+Technical+Publications.pri

nt (last accessed Jan. 29, 2014). 361 A Monte Carlo simulation is a problem solving technique that builds models of possible results by substituting a 

range of values – a probability distribution – for any factor that has inherent uncertainty. It then calculates results 

over and over, each time using a different set of random values from the probability functions. Depending on the 

uncertainties and the ranges specified for them, a Monte Carlo simulation could involve thousands or tens of 

thousands of recalculations before it is complete. Monte Carlo simulation produces distributions of possible outcome 

values.
270

Figure XII-2 SIM Logic and Structure

Severity

Reduction

Crash 

Prevention

With System

Without System

Pre-Crash

Scenarios

Driver 

response to 

conflict

Vehicle 

response to 

driver

Kinematic

vehicle-to-vehicle 

interaction

Driver 

response to 

conflict

Driver 

response to 

system

System 

detection

System 

response

Collision

Impact 

scenario

Crashes 

avoided

Crashes 

avoided

Outcome

(fatality, injury)

Outcome

(fatality, injury)

Collision

No

No

Yes

Effectiveness Effectiveness

Yes

Crash

Data

Benefits Benefits

With

W/O

Kinematic

vehicle-to-vehicle 

interaction

Vehicle 

response

Driver/Vehicle/System 

Performance Data

System 

Specifications

The SIM V2V benefit estimation process used here began with the generation of precrash scenarios using crash statistics from the National Automotive Sampling System General 

Estimate System (NASS-GES) that compiles crash data from a nationally-representative sample 

of police-reported motor vehicle crashes of all crash types. From each scenario, specific conflicts 

(a combination of driver, vehicle, and scenario characteristics) were generated using probability 

distribution-based historical data and Safety Pilot Model Deployment data.362 The distributions 

used to generate the specific conflicts included safety system performance (system activation), 

driver reaction time, braking level, and the vehicle speed/distance-to-collision distributions. The 

distributions of various characteristics support the use of a Monte Carlo approach that was used 

to run thousands of conflicts that were then evaluated with and without the safety application. 

The results from these conflict evaluations -- crashes, crashes avoided, or crashes mitigated --

were summarized, leading to system effectiveness and harm reduction ratios for the different 

scenario/safety application combinations. The effectiveness and harm reduction ratios for each 

scenario/safety application were then applied to the target population for each scenario to 

estimate the level of benefits that may result from each safety application. The collective benefits 

from the evaluated safety application provide a total estimate of benefits that can then be

compared to the estimated cost for the V2V system.

 

362 Each specific conflict is a single event with only the vehicles involved in the conflict included in the simulation.

Unintended consequences (e.g., a crash caused by avoiding a crash) that involve other non-conflict vehicles are not 

captured through the simulation.
271

Although the SIM can generate both effectiveness and benefit estimates, only the 

effectiveness outcome was used in this analysis due to some refinement to the target populations 

that would not be considered in the SIM. The process of deriving the system effectiveness for a 

safety application can be briefly summarized by the following steps:

(1) Derive the initial effectiveness for various pre-crash scenarios and speed ranges (from 

SIM or MiniSim)

(2) Derive the overall effectiveness for each pre-crash scenario by calculating the weighted 

effectiveness of initial effectiveness over all speed ranges

(3) Derive the system effectiveness by calculating the weighted effectiveness of pre-crash 

scenario effectiveness over all pre-crash scenarios

(4) Derive the final system effectiveness by multiplying the overall effectiveness by a factor 

to take into account situations that were not addressed by SIM and MiniSim.

For crashworthiness, the effectiveness Ew of an application is the effect of delta-V

reduction on crash severity for those crashes that cannot be avoided by the safety application,

where delta-V is the recorded change in velocity experienced during a crash.363 Ew was estimated 

by MAIS injury level. As stated earlier, SIM was used to generate crash impact speed 

distributions separately for the baseline and treatment groups. These speed distributions were 

used as the proxy for delta-V to estimate Ew. SIM groups the impact speeds into 16 intervals. 

The first interval is from 0 to less than 3 mph, noted as [0, 3), with 3 mph increment for the 

subsequent intervals until 46 mph. Impact speeds of 47 mph and higher were aggregated into the 

last interval notes as 47+ mph. SIM treats all involved vehicles with equal mass. Therefore, half 

of the impact speed is a substitute for delta-V of the crash. Furthermore, the mid-point of each 

interval was used to calculate the average delta-V for each pre-crash scenario. The sum of the 

products of the mid-points and their corresponding percent of distributions derives the average 

delta-V for that specific pre-crash scenario. Then, applying the percent of real-world crash 

distribution to the average delta-V derives the weighted average delta-V for a target crash type.

MAIS injury probability curves were used to locate the MAIS injury probabilities at the 

weighted average delta-V level both for control and treatment group. The effectiveness for a 

MAIS level can be noted as:

 

363 The vehicle resultant change in velocity, commonly referred to as simply resultant delta-V, is the primary 

description of crash severity in most crash databases. “Estimating Crash Severity: Can Event Data Recorders 

Replace Crash Reconstruction?” For additional information, see

www.nhtsa.gov/DOT/NHTSA/NRD/Articles/ESV/PDF/18/Files/18ESV-000490.pdf (last accessed: January 29, 

2014).
272

Equation XII-7 MAIS Effectiveness Calculation

Where, Ew = MAIS effectiveness 

Pt = injury probability for the treatment group

Pc = injury probability for the control group

The following summarizes the process for deriving Ew. A detailed description of the 

process is contained in each of the following sections dedicated to specific applications.

(1) Derive the delta-V distribution for each of the pre-crash scenarios for baseline (i.e., 

without V2V) and treatment groups (with V2V).

(2) Derive an average delta-V for each scenario for the baseline and treatment groups

(3) Derive the weighed delta-V for all scenarios combined

(4) Derive injury probability curves

(5) Estimate the MAIS injury probabilities at the weighted average delta-V level using injury 

probability curves

In the following sections dedicated to specific safety applications, the process of deriving 

crash avoidance and crashworthiness effectiveness will be discussed in detail.

2. Driving Simulator Study - MiniSim

MiniSim is a driving simulator in a controlled laboratory environment, which was used 

for evaluating IMA and LTA applications in avoiding crashes. Drivers were recruited to drive 

three IMA and two LTA pre-crash scenarios. These drivers are divided into baseline (no IMA or 

LTA warning given) and treatment (IMA or LTA warning given) groups. The crash avoidance 

effectiveness (Ea) is derived from the crash rates and reaction times of these two groups. 

A total of 144 drivers successfully completed the IMA study. Table XII-2 shows the 

experimental design and breakdown of these drivers in this study.

364 These drivers were equally 

divided into three groups of 48 for each of the three driving conditions listed above. Within a 

group, 24 drivers received an alert (treatment group) and 24 did not (baseline group). Each group

is equally divided among three age groups (18 to 24, 40 to 50, and 60 or older) and by gender 

 

364 Summary Report for a Simulator Study of Intersection Movement Assist (IMA) and Left Turn Assist (LTA) 

Warning Systems (Balk, Sept. 2013, Turner-Fairbank Highway Research Center, Internal Report). See Docket No. 

NHTSA-2014-0022. 
273

(i.e., male and female) as seen in Table XII-2. Each driver experienced only one of the three 

driving conditions.

Table XII-2 Breakdown of Drivers in IMA Study

Alert 

Condition

Age 

(Years)

Gender Driving Condition

PCP-M PCP-S 

Left

PCP-S 

Right

Baseline 

(No Alert)

18-24 Male 4 4 4

Female 4 4 4

40-50 Male 4 4 4

Female 4 4 4

≥ 60 Male 4 4 4

Female 4 4 4

Subtotal 24 24 24

Treatment 

(Alert)

18-24 Male 4 4 4

Female 4 4 4

40-50 Male 4 4 4

Female 4 4 4

≥ 60 Male 4 4 4

Female 4 4 4

Subtotal 24 24 24

Total 48 48 48

The MiniSim design for IMA is for drivers to experience one of three driving conditions 

at a four-way intersection.

1. The driver approaches the intersection with a green light and another vehicle approaches 

from the left (PCP-M)

2. The driver approaches the intersection with a stop sign and another vehicle approaches 

from the left (PCP-S)

3. The driver approaches the intersection with a stop sign and another vehicle approaches 

from the right (PCP-S)

In all conditions, the driver is traveling at 45 mph toward the intersection and attempting

to drive straight through the intersection. Just before the driver crosses into the intersection, the 

approaching vehicle, obscured by a stationary large truck, appears coming from the 

perpendicular/lateral side at a constant speed of 45 mph. If no attempt to apply the brakes was 

taken by the driver participating in the study, the vehicles would crash in 3.3 seconds.
274

The MiniSim design for LTA is for drivers to experience one of two driving conditions 

while making a left turn at an intersection.

1. The driver had a green light and could make the turn without stopping (LTAP/OD-M)

2. The driver had a red light initially and had to stop, and then made a left turn when the 

light turned green (LTAP/OD-S)

In both conditions, the driver and an approaching vehicle approach each other from 

opposite directions. As soon the driver started to initiate the left turn and exceeded 6 mph in 

speed, the approaching vehicle appeared behind the stopped truck, traveling forward at a 

constant speed of roughly 45 mph. If no action was taken by the driver, the two vehicles would 

crash in about 3.3 seconds. 

A total of 96 drivers were recruited for LTA. These drivers were evenly divided into two 

groups of 48 each and were further evenly divided into baseline and treatment.

3. Injury probability curves

Injury probability curves predict the probabilities of MAIS injuries based on delta-V. 

These curves were derived from 2000-2011 CDS data. CDS is a nationally-representative 

sampling system of passenger vehicle crashes where at least one passenger vehicle was towed.

CDS was used because it is the only nationally-representative crash database that collects both 

delta-V and MAIS. A logistic model is the base for developing these curves. The logistic model 

predicts the probability of MAIS injuries that would occur at a specific delta-V level. The 

dependent variable of the model is MAIS+ injury severity which is dichotomy. The value is 0 

when an injury is less than a certain MAIS level and 1 if an injury is equal to or greater than that 

MAIS level. Delta-V is the independent variable. 

The derived MAIS+ injury probability curves for a delta-V level “x” thus have the form:

Equation XII-8 MAIS+Injury Probability of Risk

Where, a = 0.092845, b = -1.14421 for MAIS 1+

a = 0.13527, b = -4.51842 for MAIS 2+

a = 0.16851, b = -6.33516 for MAIS 3+

a = 0.17329, b = -7.77703 for MAIS 4+

a = 0.18588, b = -9.35528 for MAIS 5+

a = 0.19471, b = -11.70930 for fatality
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The probability for certain injury level is simply the difference of two MAIS+ 

probabilities. In other words, , , and etc.

4. Crashworthiness effectiveness by MAIS 

For calculating the injury reduction rates, the delta-Vs produced for the baseline and 

treatment were input into the MAIS+ formula. Table XII-3 presents the process. As shown, given

a reduction on delta-V by 1.17 mph, IMA would mitigate MAIS 1 injuries by 6 percent, MAIS 2 

injuries by 16 percent, and MAIS 4 injuries by 50 percent. Note that at the delta-V level of 8.17 

and 7.00 mph levels, the probabilities of having MAIS 3+ injuries are small. Therefore, the 

probability estimation for MAIS 3, MAIS 4, MAIS 5, and fatality might have a greater variation 

for these injury levels.

Table XII-3 Probabilities of MAIS Injuries and Injury Reduction Effectiveness

Injury 

Severity

Probability Injury 

Severity

Probability Injury

Reduction

Rate

Baseline

(8.17 mph)

Treatment

(7.00 mph)

Baseline

(8.17 mph)

Treatment

(7.00 mph)

MAIS 1+ 0.405 0.379 MAIS 1 0.373 0.352 0.06

MAIS 2+ 0.032 0.027 MAIS 2 0.025 0.021 0.16

MAIS 3+ 0.007 0.006 MAIS 3 0.005 0.005 0.00

MAIS 4+ 0.002 0.001 MAIS 4 0.002 0.001 0.50

MAIS 5+ 0.000 0.000 MAIS 5 0.000 0.000 0.00

Fatality 0.000 0.000 Fatality 0.000 0.000 0.00

Source: 2000-2011 CDS

5. Effectiveness of Intersection Movement Assist - IMA

a) IMA Crash Avoidance Effectiveness (Ea)

The effectiveness for IMA was estimated based on two major pre-crash scenarios 

employed in the design of the MiniSim: (1) perpendicular crossing path, with the driver stopping 

and then proceeding and another vehicle approaching from either the right or the left without 

stopping (PCP-S) and (2) perpendicular crossing path, with the driver approaching the 

intersection without stopping and another vehicle approaching from the left without stopping

(PCP-M). The drivers’ measured brake reaction time and brake deceleration level collected 

during the study from both the baseline and treatment MiniSim groups were then used as inputs

into SIM to derive effectiveness values for various speed ranges for these pre-crash scenarios.

(1) Crash Avoidance PCP-S Crash Scenario

For the PCP-S crash scenario, MiniSim data was used to simulate crash outcomes for five 

different traveling speed ranges for an approaching vehicle under three separate distances 

between the driver (of the vehicle that stopped at the intersection and then proceeded) and the 

point where the driver’s vehicle would make contact with the approaching vehicle. The 

following sections describe this process.
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(a) Crash Distribution by Vehicle Speed

The agency developed a series of five bins to create a crash distribution by vehicle speed. 

For this evaluation, the approaching vehicle speed ranges evaluated were: [10, 25), [25, 35), [35, 

45), [40, 55), and 55+ mph where the pair symbol [x, y) represents that the speed is at least x 

mph but less than y mph, and the plus symbol x+ represents that the speed is x mph and higher. 

The driver speed identified for this scenario is between 0 to 9 mph, to represent a vehicle stopped 

and then proceeding into the intersection. The agency developed the crash distribution shown in 

Table XII-4 by using these identified speed ranges as parameters in the SIM tool’s Monte Carlo 

analysis.

Table XII-4 Percent of Crash Distribution* by Approaching Vehicle Traveling Speed (pi)

Driver Vehicle 

Speed

Approaching Vehicle Travel Speed (mph)

(mph) [10, 25) [25, 35) [35, 45) [45, 55) 55+

[0 , 10) 11.89% 9.88% 8.76% 2.95% 1.05%

*served as weight for calculating weighted effectiveness; already adjusted for unknown speed

Source: 2010-2011 GES

(b) Vehicle to Vehicle Distances Evaluated

The distance between the driver and approaching vehicle evaluated were: 3-5 meters, 4 

meters, and 5-8 meters. Furthermore, the simulation was further refined by the impact location of 

the approaching vehicle, i.e., the left or right side of the vehicle, based on the percentages 

identified in Table XII-5.

Table XII-5 Percent of Impact Location*

Left Side Impact 53.12%

Right Side Impact 46.88%

*served as weight for calculating weighted effectiveness; already adjusted for unknown speed

Source: 2010-2011 GES

(c) IMA PCP-S Effectiveness Calculation

The IMA PCP-S scenario thus encompassed 30 initial effectiveness values, given 5 speed 

ranges * 2 vehicle impact locations * 3 separating distances. The weighted effectiveness for all 

five speed ranges and impact locations was calculated for each separating distance. This 

weighted effectiveness was then applied to the percentage of PCP-S crashes that occur in all 

IMA crashes to calculate the weighted effectiveness (Ea) using the following mathematical 

formula:
277

Equation XII-9 IMA PCP-S Crash Effectiveness Calculation

Where, Ea = weighted effectiveness

R = proportion of PCP-S right side impact

Pi = proportion of PCP-S in speed range i, with i=1 for [10,25) and 5 for 50+ mph

= effectiveness for speed range I for right side impact.

= effectiveness for speed range I for left side impact.

Table XII-6 provides the 30 effectiveness values calculated for using this methodology:

Table XII-6 SIM Estimated Initial Effectiveness ( and )

Separating Remote Vehicle Travel Speed (mph)

Distance (m) [10 , 25) [25, 35) [35, 45) [45, 55) 55+

Left Side

3-5 0.71 0.66 0.64 0.56 0.45

4 0.81 0.78 0.66 0.55 0.41

5-8 0.70 0.67 0.53 0.43 0.32

Right Side

3-5 0.70 0.70 0.64 0.59 0.48

4 0.83 0.79 0.70 0.59 0.44

5-8 0.73 0.65 0.56 0.47 0.35

(d) Summary of IMA PCP-S Effectiveness

The agency did not employ all of these initial effectiveness estimates in developing our 

ultimate estimate of IMA effectiveness in the PCP-S scenario. Instead, we focused on two crash 

distributions that best reflected our understanding of current and future system capabilities in 

real-world situations. Using the two distribution results in estimating a range of effectiveness that 

reflects the current limitation of the current prototype (but does not limit the potential impact that 

IMA could have on the target population it could address).

The first distribution does not include the crashes that occur between 10 to 24 mph, [10,

25), because current prototype IMA designs (like those used in the Safety Pilot model 

deployment) do not issue warnings unless one of the interacting vehicles is traveling at or above 

25 mph. This means that the effectiveness of IMA is treated as 0 for these crashes in the first 

distribution. The second distribution, on the other hand, includes the [10, 25) speed interval, in 
278

order to reflect our expectation that future improvements to IMA will allow the application to 

operate down to 10 mph.

Using these two distributions reduced the initial set of 30 effectiveness values to a total of 

3 weighted effectiveness values (as shown in Table XII-7, the agency estimates IMA would 

avoid 15-24 percent of PCP-S crashes), which we used for benefits estimation.

Table XII-7 Weighted IMA Effectiveness (Ea) for PCP-S Crash Scenario

Separating Distance

3-5 meters 4 meters 5-8 meters

Low 0.15 0.16 0.15

High 0.23 0.24 0.24

The three weighted effectiveness values were later combined with the weighted crash 

avoidance effectiveness (Ea) for the PCP-M crash scenario, discussed below, to derive the final 

effectiveness for IMA.

(2) Crash Avoidance PCP-M Crash Scenario

For the PCP-M crash scenario, as for the PCP-S crash scenario, data generated by the 

MiniSim study was used as input to the SIM. The PCP-M evaluation is slightly more 

straightforward than for PCP-S for two reasons: first, PCP-M involves both vehicles moving, and 

second, PCP-M only involves the “other vehicle” approaching the driver from the left. As a 

result, the full range of vehicle speeds apply to both the driver and the approaching vehicle, and 

no accounting for vehicle impact side or vehicle to vehicle distance is evaluated.

(a) Crash Distribution by Vehicle Speeds

The same series of five bins ([10, 25), [25, 35), [35, 45), [40, 55), and 55+ mph) were 

used to develop a crash distribution by vehicle speed as for the PCP-S crash scenario, but since 

all five speed range bins are considered applicable and evaluated for both the driver and 

approaching vehicles, 25 crash distribution values result instead of the 5 values for PCP-S. 

Table XII-8 Percent of Crash Distribution* by Approaching Vehicle Traveling Speed (pi) 

Driver Vehicle 

Speed

Approaching Vehicle Travel Speed (mph)

(mph) [10 , 25) [25, 35) [35, 45) [45, 55) 55+

[10 , 25) 13.01% 11.00% 10.76% 3.50% 0.78%

[25, 35) 5.23% 3.80% 1.87% 0.85% 0.10%

[35, 45) 3.43% 1.09% 1.73% 0.58% 0.07%

[45, 55) 1.29% 0.37% 0.44% 0.65% 0.10%

55+ 0.41% 0.03% 0.24% 0.07% 0.07%

*served as weight for calculating weighted effectiveness; already adjusted for unknown speed

Source: 2010-2011 GES
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(b) IMA PCP-M Effectiveness Calculation

Using the same effectiveness calculation method as that for PCP-S, a total of 25 initial 

effectiveness values were generated by the SIM for the IMA PCP-M scenario. The reader will 

remember that in PCP-M, we did not consider vehicle impact side or vehicle separating distance, 

so the 25 initial effectiveness values reflect only the interactions of the two vehicles depending 

on their speed.

As discussed above for PCP-S, the initial effectiveness for the cell “driver vehicle speed 

[10, 25),” “approaching vehicle speed [10, 25)” was not used (i.e., treated as 0) for the 

effectiveness calculation given current system limitations that cause IMA not to activate below 

25 mph. This cell is therefore shaded gray in Table XII-9. The wide range illustrates the 

uncertainty concern on the inherent computation variations including those from SIM, MiniSim, 

and GES sampling errors.

Table XII-9 SIM Estimated Initial Effectiveness (Ea)

Driver 

Vehicle Speed

Approaching Vehicle Travel Speed (mph)

(mph) [10 , 25) [25, 35) [35, 45) [45, 55) 55+

[10 , 25) 0.47 0.51 0.55 0.57 0.60

[25, 35) 0.41 0.50 0.56 0.59 0.63

[35, 45) 0.43 0.54 0.60 0.63 0.67

[45, 55) 0.46 0.58 0.63 0.66 0.69

55+ 0.49 0.62 0.66 0.67 0.69

(c) Summary of IMA PCP-M Effectiveness 

Using the same methodology as the PCP-S crash scenario, the agency developed a 

weighted estimated effectiveness of 26 to 31 percent for IMA when a driver is involved in the 

PCP-M crash scenario. However, the agency again notes that the lower bound of effectiveness 

reflects the current prototype design of IMA, where a warning is issued when the driver is 

traveling above 25 mph. As mentioned above, it is anticipated that future tuning of the IMA 

application would allow it to operate at speeds as low as 10 mph.

(3) IMA Crash Avoidance System Effectiveness

The overall IMA system effectiveness is calculated by combining the effectiveness 

values of the PCP-S and PCP-M crash scenarios. This is possible because the weighted 

effectiveness values for these crash scenarios took into account the corresponding crash 

proportion for each scenario. Therefore, the overall system effectiveness is simply the sum of 

these two weighted effectiveness rates.

Based on the combination of the IMA PCP-S and PCP-M effectiveness values, the 

agency estimates IMA has the potential to help drivers avoid 41 to 55 percent of intersection 
280

crashes.

365 In other words, the agency estimates that by providing a warning that an intersection 

crash is about to occur, drivers will avoid 41 to 55 percent of all target IMA intersection crashes.

b) IMA Crashworthiness Effectiveness (Ew)

The crashworthiness effectiveness (Ew) for IMA was developed using crash impact speed 

distributions generated by the SIM. As discussed in Section XII.B.1, these crash impact 

distributions were used as the proxy for delta-V distributions. Additionally, injury probability 

curves for this analysis were derived as described in Section XII.B.3

(1) Crashworthiness PCP-S Crash Scenario

Estimates for the IMA Crashworthiness PCP-S scenario were developed based on 15 

crash conditions for each impact location – left or right side (i.e., approaching vehicle traveling 

speeds, left and right impact locations, three separating distances). These 15 conditions were 

simulated using the SIM tool to produce delta-V distributions for both the baseline and treatment 

groups for comparison. Details for each distribution are shown in Table XIII-2 and Table XIII-3, 

respectively.

Table XII-10 shows the average delta-Vs that were derived by multiplying the delta-V by 

its corresponding distribution percentage.

Table XII-10 Derived Average Delta-V (mph) by Simulated Crash Conditions

Separating Baseline Treatment

Distance Approaching Vehicle Speed (mph) Approaching Vehicle Speed (mph)

(Meter) [10, 

25)

[25, 

35)

[35, 

45)

[45, 

55) 55+ [10, 25) [25, 35) [35, 45) [45, 55) 55+

Left Side Impact

3-5 4.01 5.80 6.94 7.63 7.74 3.63 5.29 6.19 6.87 6.85

4 3.95 5.38 6.68 7.54 7.50 3.58 4.91 6.26 6.77 6.92

5-8 3.97 4.90 5.45 5.93 6.06 3.37 4.1 4.72 6.4 5.79

Right Side Impact

3-5 5.78 6.98 7.68 7.72 5.29 6.19 6.87 6.85

4 4.12 5.50 6.60 7.93 7.57 3.58 4.91 6.26 6.77 6.92

5-8 3.77 4.27 4.95 5.44 5.18 3.37 4.1 4.72 6.4 5.79

Applying the crash distribution based on approaching vehicle traveling speed categories 

shown in Table XII-11 to the average delta-V provides the average delta-V for PCP-S crash 

scenarios.

 

365 The result of adding 15 – 24 percent for PCP-S and 26 - 31 percent for PCP-M.
281

Table XII-11 Traveling Speed Distribution*

Approaching Vehicle Speed (mph)

[10 , 25) [25, 35) [35, 45) [45, 55) 55+

0.3091 0.2568 0.2277 0.0767 0.0273

*used as weight to calculate the delta-V level for an average PCP-S

As shown in Table XII-12, the average delta-V ranged from 4.16 to 4.95 mph for baseline 

crashes (without V2V) and 3.82 to 4.50 mph for treatment crashes (with V2V). This tells us that 

when a driver is stopped at an intersection, decides to go, and has a crash, the difference in the 

delta-V of that crash with or without a V2V warning is relatively small. The real benefit of V2V 

relates to the go/no go decision, and avoiding the crash by V2V warning the driver of the 

impending crash and the driver deciding not to go into the intersection.

Table XII-12 Delta-V for an Average PCP-S Crash

Separating Distance Baseline Treatment

3-5 4.53 4.08

4 4.95 4.50

5-8 4.16 3.82

(2) Crashworthiness PCP-M Crash Scenario

For the IMA PCP-M crash scenario, the process of deriving the delta-V for an average 

PCP-M crash is similar to that for PCP-S. The only difference between the two is the simulated 

crash conditions. There were 25 conditions for PCP-M, representing the combinations of five 

drivers and five approaching vehicles. Table XII-13 and Table XII-14show the parallel process

to the PCP-S crash scenario for generating an average crash delta-V for a PCP-M crash.

Table XII-13 Derived Average Delta-V (mph) by Simulated Crash Conditions

Host Baseline Treatment

Vehicle Approaching Vehicle Speed (mph) Approaching Vehicle Speed (mph)

Speed [10, 25) [25, 35) [35, 45) [45, 55) 55+ [10, 25) [25, 35) [35, 45) [45, 55) 55+

[10, 25) 7.73 7.73 7.75 7.77 7.83 5.36 5.84 6.25 6.42 6.82

[25, 35) 12.68 12.75 12.87 12.96 13.1 8.52 9.74 10.48 10.85 11.5

[35, 45) 16.21 16.45 16.67 16.86 17.21 11.62 13.51 14.51 15.07 15.94

[45, 55) 19.41 19.93 20.33 20.57 21.05 14.97 17.63 18.85 19.53 20.52

55+ 21.38 22.09 22.51 22.74 23.04 18.28 21.34 22.35 22.81 23.2
282

Table XII-14 Traveling Speed Distribution*

Host Vehicle Approaching Vehicle Speed (mph)

Speed [10 , 25) [25, 35) [35, 45) [45, 55) 55+

[10, 25) 21.16% 17.89% 17.50% 5.69% 1.27%

[25, 35) 8.51% 6.18% 3.04% 1.38% 0.16%

[35, 45) 5.58% 1.77% 2.81% 0.94% 0.11%

[45, 55) 2.10% 0.60% 0.72% 1.06% 0.16%

55+ 0.67% 0.05% 0.39% 0.11% 0.11%

*used as weight to calculate the delta-V level for an average PCP-S

As shown in Table XII-15, the delta-V for a baseline PCP-M is estimated to be 10.43 

mph and for a treatment PCP-M is about 8.06 mph. IMA would reduce the crash severity by 2.37 

mph. Thus, when both vehicles are moving before an intersection crash, and the crash still 

occurs, providing a V2V warning does reduce the delta-V of the crash by a noticeable level of 

2.37 mph on average.

Table XII-15 Delta-V for an Average PCP-M Crash

Baseline Treatment

Delta-V (mph) 10.43 8.06

c) IMA Crashworthiness System Effectiveness

For IMA crashes as a whole, i.e., PCP-S and PCP-M combined, the average delta-V for 

IMA crashes is the weighted average of individual delta-Vs for PCP-S and PCP-M. Of the IMA 

crashes, PCP-S comprised about 38.97 percent of the crashes and PCP-M comprised 61.03 

percent of the crashes. Applying these factors to the corresponding individual delta-V shown in 

Table XII-12 and Table XII-15 derives the average delta-V for IMA crashes. For the baseline 

IMA crashes, the average delta-V is about 8.17 mph and 7.00 mph for a treatment IMA crash.

IMA would reduce the severity of IMA crashes by an average of 1.17 mph delta-V.

The average delta-V of 8.17 mph and 7.00 mph for the baseline and treatment IMA 

crashes were then input into the injury probability curves to assess the probability that a person 

would receive a certain level of MAIS injuries. The resulting probabilities for the baseline and

treatment groups were used to estimate the reduction rate (i.e., crashworthiness effectiveness) for 

each of MAIS level.

6. Effectiveness of Left Turn Assist - LTA

a) LTA Effectiveness Analysis Overview

LTA is designed to assist the driver of the left turning vehicle in deciding whether to 

proceed with a left-turn maneuver at an intersection. LTA is not expected to influence the 

movement of an approaching vehicle. As such, LTA is considered to have no impact on 
283

mitigating the severity of the LTA crashes that cannot be avoided and no crashworthiness 

effectiveness is estimated for LTA in this analysis.

The effectiveness of Left Turn Assist, Ea for LTA, is based on the MiniSim results from 

96 volunteer drivers. For each condition, half of drivers experienced an alert (the treatment 

group) and half did not (the control group). Therefore, for each group, only one set of 

effectiveness was used for each of the LTA pre-crash conditions.

b) LTA Crash Scenarios

LTA target crashes were categorized into two pre-crash scenarios that correspond to the 

crash design of MiniSim:

• Left Turn Across Path, Opposite Direction: an approaching vehicle continues to cross 

straight while the driver continues to move and turns left across the path of the other.

This is scenario is abbreviated as LTAP/OD – M for moving.

• Left Turn Across Path, Opposite Direction: an approaching vehicle continues to cross 

straight while the driver first stops and later turns left across the path of the other. This is 

scenario is abbreviated as LTAP/OD – S for stopped.

(1) LTAP/OD – M MiniSim Test Scenario

In the LTAP/OD – M simulation, the driver approaches an intersection and is asked to 

turn left through a green light. There is a stopped truck waiting to turn left, blocking the vision of 

the subject driver of the next lane over. As the driver enters the intersection, a vehicle approaches 

the intersection along the side of the stopped truck.

(2) LTAP/OD – S MiniSim Test Scenario

In the LTAP/OD – S condition, the driver approaches the same intersection but the light 

is red. The driver must stop and then when the light turns green and the driver initiates the turn 

and reaches 6 mph, the approaching vehicle appears and approaches the intersection with a 

constant speed of 45 mph. 

c) LTA Effectiveness Analysis Assumptions

The effectiveness analysis for LTA crashes identifies some scenarios or conditions where 

LTA may not be effective or operate properly. In these conditions, such as where the 

approaching vehicle speed is less than 10 mph, LTA effectiveness is treated as 0. In this very low 

speed condition, there is the possibility of many false alarms being issued and manufacturers 

may very well choose not to implement LTA to be active in this condition.

d) LTA Effectiveness Analysis Results

Based on the 96 volunteer driver results, LTA would prevent 75 percent of LTAP-M 

crashes and 33 percent of LTAP-S crashes. These effectiveness rates then were weighted by their 
284

corresponding crash proportion to derive the overall Ea. As shown in Table XI-16, LTA would 

prevent 48 - 62 percent of LTA crashes. However, according to the current design of LTA, LTA 

would be activated only when the left turn signal is initiated. Otherwise, you would constantly be 

given a warning every time a vehicle approached from the other direction.

Based on an SAE study by Richard Ponziani, about 75 percent of drivers would use the 

turn single when making left turns. Therefore, the derived effectiveness at lower bound was 

further discounted by 25 percent to 36 percent (48*0.75 = 0.36). This serves as the lower bound 

of final LTA effectiveness. The agency believes that, if drivers realized the benefit of LTA over 

time, drivers would be more likely to use the turn single when turning.

Table XII-16 Effectiveness for LTAP-M and LTAP-S

LTAP-M LTAP-S

Effectiveness 75% 33%

Crash Proportion*

Low 0.5570 0.1942

High 0.7140 0.2434

*sum does not add up to100% because some LTA crashes do not belong to either of these conditions

Therefore, the 62 percent is treated as the high bound of the effectiveness. LTA would 

avoid 36 to 62 percent of the LTA crashes. The wide range addresses the uncertainty for the 

estimate.

Table XII-17 System Effectiveness

Low High

Initial 48% 62%

Final** 36% 62%

**Adjusted for turn signal use but only for lower bound

7. Summary of IMA and LTA effectiveness

Table XII-18 summarizes the crash avoidance and crashworthiness effectiveness for IMA 

and LTA that were derived from the previous sections. As shown, IMA would prevent 41-55 

percent of IMA crashes and LTA would prevent 36-62 percent of LTA crashes.

Table XII-18 System Effectiveness of IMA and LTA

Crash Avoidance (Ea)

IMA LTA

Low 41% 36%

High 55% 62%
285

Crashworthiness (Ew)

Injury 

Severity

IMA LTA

MAIS 1 6% Not Applicable (NA)

MAIS 2 16% NA

MAIS 3 0% NA

MAIS 4 50% NA

MAIS 5 0% NA

Fatality 0% NA

C. Fleet communication rate (Ci)

The probability that two vehicles can communicate with each other depends on the 

number of V2V-equipped vehicles (OBE, ASD, and VAD) and the total number of on-road 

operational passenger vehicles (i.e., the registered vehicles). The number of V2V-equipped

vehicles varies with the technology implementation scenarios. The number of on-road 

operational passenger vehicles was derived from the estimates of new vehicle sales and the 

scrappage rate of vehicles. Readers can consult Appendix A for the technology plan and the 

detailed process of estimating the on-road light vehicle fleet.

The communication rate Ci for two V2V-equipped vehicles encountered at the ith year 

can be noted as:

Equation XII-10 Communication Rate Calculation

, i.e., ,

Where Ni represents the total number of vehicles that had equipped either OBE or ASD, 

Oi represents the total on-road light vehicle fleet for year i. Note that any two vehicles that can 

communicate with each other should be treated as selection without replacement. In other words, 

Ci should be . However, Ni and Oi are large. The two values, and , are 

almost identical. For simplicity, the square form is used for calculating the communication rate 

Ci. Also note that the difference in Ci among geographic areas and driving patterns by different 

age of vehicles were not examined in the analysis since these factors are not expected to impact 

the overall communication rate at the national level.

Table XIII-5 shows the communication rates from 2020 to 2059 for the three technology 

implementation scenarios. As shown, the communication rates for Scenarios 1 and 2 accelerate 

faster as time passes. It will take 12 years to reach the 50 percent communication rate for 

Scenario 1, but only five years later (i.e., at year 17), the communication rate would reach 75 

percent. Scenario 2 would reach the 50 and 75 communication rates three years later than

Scenario 1. As expected, the communication rate for Scenario 3 is low. The disparity among 
286

these three scenarios demonstrates the impact of the implementation pace on communication 

rate, and thus on benefits. Note that the V2V benefit can be realized only when one of the 

involved vehicles is equipped with safety applications. The communication rate for Scenario 2 

represents the communication rate between two vehicles where at least one of them had safety 

applications.

The communication rates were further segregated by vehicle type (i.e., PCs and LTVs).

Communication rate for PCs is the probability for PCs communicating among PCs plus the 

probability that PCs are communicating with LTVs. Similarly, communication rate for LTVs is 

the probability of LTVs communicating among LTVs plus the probability of LTVs 

communicating with PCs. The communication rates for PCs and LTVs are later used to divide

the overall annual benefits into PC and LTV portions of benefits for calculating benefits by 

vehicle model year (MY). Table XIII-6 shows the communication rates by vehicle types.

D. Projected benefits of V2V technology

This section provides the undiscounted preliminary annual maximum benefits, annual 

benefit by calendar years. Benefits can be derived by multiplying these three factors: target 

population, the effectiveness, and the communication rates as mathematically noted in using 

Equation XII-1. The maximum represent the benefits when all on-road passenger vehicles were 

equipped with DSRC and IMA and LTA safety applications. The maximum benefits would be 

achievable under Scenarios 1 and 2 but not Scenario 3. The maximum benefits are discussed first 

and followed by three parallel sections, each for a scenario, describing the annual estimated 

benefits per calendar year.

1. Maximum annual estimated benefits

Table XII-19 shows the non-discounted annual preliminary maximum estimated benefits 

based on all passenger vehicles (PVs) being equipped with only IMA and LTA and the 

communication rate reaches 100 percent among PVs. The maximum estimated benefit would be 

identical for the first two technology implementation scenarios. The difference among the two

scenarios is when (i.e., how fast) the maximum estimated benefit can be achieved. The third 

scenario would not achieve this maximum benefit level since the communication rate for this 

scenario would not reach 100 percent. As shown, IMA and LTA combined would prevent 

412,512 to 592,230 crashes, save 777 to 1,083 lives, reduce 191,202 to 270,011 MAIS 1-5 

injuries, and eliminate 511,118 to 728,173 property-damage-only vehicles (PDOVs).

Of the above estimated benefits, IMA would prevent 310,451 to 416,458 crashes, save 

671 to 900 lives, reduce 136,959 to 176,593 MAIS 1-5 injuries, and eliminate 399,431 to 

535,823 PDOVs. LTA would avoid 102,061 to 175,772 crashes, save 106 to 183 lives, reduce 

54,243 to 93,418 MAIS 1-5 injuries, and eliminate 111,687 to 192,350 PDOVs.
287

Table XII-19 Non-Discounted Annual Preliminary Maximum Estimated Benefit Summary

All Passenger Vehicles Equipped With V2V Technology

IMA LTA Combined

Low High Low High Low High

Crashes 310,451 416,458 102,061 175,772 412,512 592,230

Fatalities 671 900 106 183 777 1,083

MAIS 1-5 Injuries 136,959 176,593 54,243 93,418 191,202 270,011

PDOV** 399,431 535,823 111,687 192,350 511,118 728,173

*Based on only IMA and LTA safety applications

**Property Damage Only Vehicles

2. Annual Estimated Benefits by Calendar Year

a) Scenario 1

Table XIII-7 shows the undiscounted preliminary estimated benefits by calendar year, 

separately for the three technology implementation scenarios. As expected, the potential benefits 

realized by IMA and LTA accrue more slowly for the first few years due to the slow build-up of 

communication rate among PVs. As shown, at Year 2020, the first year of technology 

implementation, IMA and LTA could potentially prevent 248-355 crashes and potentially avoid 

412,000 to 592,000 crashes annually after 36 years of implementation.

b) Scenario 2

Table XIII-8 shows the undiscounted preliminary benefit estimates by calendar year for 

Scenario 2. As shown, at Year 2020, the first year of technology implementation, this scenario

could potentially prevent 124 to 178 crashes, about 50 percent of the level that can be achieved 

by Scenario 1. After 10 years of implementation, in Year 2030, this scenario could potentially

prevent 121,526 to 174,471 crashes, about 80 percent of the level in Scenario 1. Eventually, 

Scenario 2 would reach a similar level of annual benefits as Scenario 1, after 38 years of 

implementation in Year 2058 and potentially prevent 412,000 to 591,000 crashes annually.

c) Scenario 3

Table XIII-9 shows the undiscounted preliminary benefit estimates by calendar year for 

this scenario. As shown, Scenario 3 appears that it would have negligible impact on safety for the 

first year of implementation of the IMA and LTA safety applications. Starting in the second year, 

the benefits for this scenario are estimated to gradually increase. After 38 years of 

implementation, in Year 2058, a potential of 25,782 to 37,014 crashes could be prevented, 49 to 

68 lives could be saved, and 11,950 to 16,876 MAIS 1-5 injuries would be reduced. The 

preliminary benefits from Scenario 3 are about six percent of the maximum benefits that could 

be achieved by Scenarios 1 and 2. The disparity in preliminary benefits demonstrates that in 

order to realize the full potential of V2V technology, achieving full implementation over time is 

critical.
288

XIII. Appendix A: Tables

Table XIII-1 RSE Data Cost per Vehicle

Scenario 1 Scenario 2 Scenario 3

Year 4 $11.63 $10.74 $8.58

Year 5 $5.37 $4.93 $3.37

Year 6 $5.98 $5.45 $3.89

Year 7 $6.60 $5.98 $4.44

Year 8 $7.21 $6.49 $6.49

Year 9 $7.83 $6.98 $6.98

Year 10 $8.45 $7.49 $7.49

Year 11 $9.06 $7.96 $7.96

Year 12 $9.68 $8.43 $8.43

Year 13 $10.29 $8.90 $8.90

Year 14 $10.91 $9.38 $9.38

Year 15 $11.52 $9.81 $9.81

Year 16 $10.53 $8.88 $8.88

Year 17 $9.24 $7.72 $7.72

Year 18 $9.24 $7.65 $7.65

Year 19 $15.78 $12.97 $12.97

Year 20 $11.11 $9.04 $9.04

Year 21 $11.11 $8.94 $8.94

Year 22 $11.11 $8.81 $8.81

Year 23 $11.11 $9.11 $9.11

Year 24 $11.11 $9.06 $9.06

Year 25 $11.11 $9.01 $9.01

Year 26 $11.11 $8.96 $8.96

Year 27 $11.11 $8.91 $8.91

Year 28 $11.11 $8.86 $8.86

Year 29 $11.11 $8.81 $8.81

Year 30 $11.11 $8.77 $8.77

Year 31 $10.17 $7.99 $7.98

Year 32 $9.24 $7.25 $7.25

Year 33 $9.24 $7.25 $7.25

Year 34 $15.78 $12.39 $12.39

Year 35 $11.11 $8.72 $8.72

Year 36 $11.11 $8.72 $8.72

Year 37 $11.11 $8.72 $8.72

Year 38 $11.11 $8.72 $8.72

Year 39 $11.11 $8.72 $8.72

Year 40 $11.11 $8.72 $8.72
289

Table XIII-2 PCP-S Scenario - Delta-V* Distribution by Approaching Vehicle Traveling 

Speed Baseline (Without V2V)

Left Side Impact Right Side Impact

Delta-V Approaching Vehicle Travel Speed (mph) Approaching Vehicle Travel Speed (mph)

(mph) [10, 25) [25, 35) [35, 45) [45, 55) 55+ [10, 25) [25, 35) [35, 45) [45, 55) 55+

Separating Distance: 3-5 Meters

0.75 8.0% 6.6% 6.1% 6.5% 6.6% 6.6% 6.1% 6.5% 6.6%

2.25 25.2% 21.2% 20.4% 21.7% 19.7% 21.1% 20.5% 21.8% 19.6%

3.75 43.4% 42.5% 43.0% 40.6% 41.7% 42.3% 43.2% 40.8% 41.6%

5.25 9.1% 6.6% 7.5% 9.1% 9.7% 6.6% 7.6% 9.1% 9.7%

6.75 3.8% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

8.25 3.6% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

9.75 3.6% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

11.25 3.1% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

12.75 0.2% 7.3% 0.0% 0.0% 0.0% 7.2% 0.0% 0.0% 0.0%

14.25 0.0% 7.1% 0.0% 0.0% 0.0% 7.0% 0.0% 0.0% 0.0%

15.75 0.0% 6.4% 0.0% 0.0% 0.0% 6.4% 0.0% 0.0% 0.0%

17.25 0.0% 2.3% 5.4% 0.0% 0.0% 2.3% 5.4% 0.0% 0.0%

18.75 0.0% 0.0% 7.1% 0.0% 0.0% 0.0% 7.1% 0.0% 0.0%

20.25 0.0% 0.0% 7.2% 0.0% 0.0% 0.0% 7.3% 0.0% 0.0%

21.75 0.0% 0.0% 3.2% 4.2% 0.0% 0.0% 3.3% 4.2% 0.0%

23.25 0.0% 0.0% 0.0% 18.0% 22.3% 0.0% 0.0% 18.1% 22.2%

Separating Distance: 4 Meters

0.75 8.0% 5.7% 5.1% 4.3% 4.2% 8.3% 5.8% 5.1% 4.6% 4.3%

2.25 24.2% 21.7% 21.0% 20.5% 19.3% 25.3% 22.2% 20.7% 21.6% 19.4%

3.75 46.1% 46.8% 45.5% 44.2% 45.5% 48.2% 47.8% 45.0% 46.5% 45.9%

5.25 8.5% 6.7% 7.1% 9.7% 10.4% 8.9% 6.9% 7.1% 10.2% 10.5%

6.75 3.8% 0.0% 0.0% 0.0% 0.0% 4.0% 0.0% 0.0% 0.0% 0.0%

8.25 3.3% 0.0% 0.0% 0.0% 0.0% 3.4% 0.0% 0.0% 0.0% 0.0%

9.75 2.8% 0.0% 0.0% 0.0% 0.0% 2.9% 0.0% 0.0% 0.0% 0.0%

11.25 3.0% 0.0% 0.0% 0.0% 0.0% 3.1% 0.0% 0.0% 0.0% 0.0%

12.75 0.1% 6.3% 0.0% 0.0% 0.0% 0.1% 6.4% 0.0% 0.0% 0.0%

14.25 0.0% 5.9% 0.0% 0.0% 0.0% 0.0% 6.1% 0.0% 0.0% 0.0%

15.75 0.0% 5.4% 0.0% 0.0% 0.0% 0.0% 5.6% 0.0% 0.0% 0.0%

17.25 0.0% 1.4% 5.3% 0.0% 0.0% 0.0% 1.4% 5.3% 0.0% 0.0%

18.75 0.0% 0.0% 6.2% 0.0% 0.0% 0.0% 0.0% 6.1% 0.0% 0.0%

20.25 0.0% 0.0% 6.9% 0.0% 0.0% 0.0% 0.0% 6.8% 0.0% 0.0%

21.75 0.0% 0.0% 2.8% 3.8% 0.0% 0.0% 0.0% 2.8% 3.9% 0.0%

23.25 0.0% 0.0% 0.0% 17.5% 20.6% 0.0% 0.0% 0.0% 18.4% 20.8%

Separating Distance: 5-8 Meters

0.75 4.9% 2.4% 1.0% 0.7% 0.0% 4.7% 2.1% 0.9% 0.6% 0.0%

2.25 23.5% 15.8% 9.4% 9.5% 10.3% 22.3% 13.8% 8.6% 8.7% 8.8%

3.75 33.6% 30.4% 31.4% 33.3% 28.4% 31.8% 26.5% 28.5% 30.5% 24.3%

5.25 31.7% 38.9% 46.7% 42.7% 45.5% 30.1% 33.9% 42.4% 39.2% 38.8%

6.75 4.2% 6.0% 4.6% 6.0% 7.9% 4.0% 5.2% 4.1% 5.5% 6.8%

8.25 0.7% 0.0% 0.0% 0.0% 0.0% 0.7% 0.0% 0.0% 0.0% 0.0%

9.75 0.7% 0.0% 0.0% 0.0% 0.0% 0.6% 0.0% 0.0% 0.0% 0.0%

11.25 0.7% 0.0% 0.0% 0.0% 0.0% 0.6% 0.0% 0.0% 0.0% 0.0%

12.75 0.0% 1.5% 0.0% 0.0% 0.0% 0.0% 1.3% 0.0% 0.0% 0.0%

14.25 0.0% 2.2% 0.0% 0.0% 0.0% 0.0% 1.9% 0.0% 0.0% 0.0%
290

Left Side Impact Right Side Impact

Delta-V Approaching Vehicle Travel Speed (mph) Approaching Vehicle Travel Speed (mph)

(mph) [10, 25) [25, 35) [35, 45) [45, 55) 55+ [10, 25) [25, 35) [35, 45) [45, 55) 55+

15.75 0.0% 2.3% 0.0% 0.0% 0.0% 0.0% 2.0% 0.0% 0.0% 0.0%

17.25 0.0% 0.4% 2.1% 0.0% 0.0% 0.0% 0.4% 1.9% 0.0% 0.0%

18.75 0.0% 0.0% 2.9% 0.0% 0.0% 0.0% 0.0% 2.7% 0.0% 0.0%

20.25 0.0% 0.0% 0.8% 0.0% 0.0% 0.0% 0.0% 0.7% 0.0% 0.0%

21.75 0.0% 0.0% 1.0% 0.7% 0.0% 0.0% 0.0% 0.9% 0.6% 0.0%

23.25 0.0% 0.0% 0.0% 7.2% 7.9% 0.0% 0.0% 0.0% 6.6% 6.8%

*equivalent to half of the crash impact speed

Source: SIM simulation output
291

Table XIII-3 PCP-S Scenario - Delta-V* Distribution by Approaching Vehicle Traveling 

Speed Treatment (With V2V)

Left Side Impact Right Side Impact

Delta-V Approaching Vehicle Speed (mph) Approaching Vehicle Speed (mph)

(mph) [10, 25) [25, 35) [35, 45) [45, 55) 55+ [10, 25) [25, 35) [35, 45) [45, 55) 55+

Separating Distance: 3-5 Meters

0.75 16.7% 15.8% 16.5% 15.8% 16.3% 15.8% 16.5% 15.8% 16.3%

2.25 31.4% 30.6% 29.6% 31.5% 30.9% 30.6% 29.6% 31.5% 30.9%

3.75 29.7% 26.4% 27.5% 28.2% 27.2% 26.4% 27.5% 28.2% 27.2%

5.25 7.8% 4.5% 5.0% 3.6% 5.1% 4.5% 5.0% 3.6% 5.1%

6.75 3.9% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

8.25 3.9% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

9.75 3.8% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

11.25 2.7% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

12.75 0.2% 7.9% 0.0% 0.0% 0.0% 7.9% 0.0% 0.0% 0.0%

14.25 0.0% 7.3% 0.0% 0.0% 0.0% 7.3% 0.0% 0.0% 0.0%

15.75 0.0% 5.6% 0.0% 0.0% 0.0% 5.6% 0.0% 0.0% 0.0%

17.25 0.0% 1.9% 5.3% 0.0% 0.0% 1.9% 5.3% 0.0% 0.0%

18.75 0.0% 0.0% 6.5% 0.0% 0.0% 0.0% 6.5% 0.0% 0.0%

20.25 0.0% 0.0% 7.2% 0.0% 0.0% 0.0% 7.2% 0.0% 0.0%

21.75 0.0% 0.0% 2.4% 4.5% 0.0% 0.0% 2.4% 4.5% 0.0%

23.25 0.0% 0.0% 0.0% 16.4% 20.4% 0.0% 0.0% 16.4% 20.4%

Separating Distance: 4 Meters

0.75 16.2% 16.1% 12.5% 13.3% 13.5% 16.2% 16.1% 12.5% 13.3% 13.5%

2.25 32.3% 31.2% 31.2% 32.5% 31.2% 32.3% 31.2% 31.2% 32.5% 31.2%

3.75 30.2% 28.0% 29.1% 28.5% 28.4% 30.2% 28.0% 29.1% 28.5% 28.4%

5.25 8.1% 5.7% 6.2% 5.8% 6.6% 8.1% 5.7% 6.2% 5.8% 6.6%

6.75 3.6% 0.0% 0.0% 0.0% 0.0% 3.6% 0.0% 0.0% 0.0% 0.0%

8.25 3.5% 0.0% 0.0% 0.0% 0.0% 3.5% 0.0% 0.0% 0.0% 0.0%

9.75 3.1% 0.0% 0.0% 0.0% 0.0% 3.1% 0.0% 0.0% 0.0% 0.0%

11.25 3.0% 0.0% 0.0% 0.0% 0.0% 3.0% 0.0% 0.0% 0.0% 0.0%

12.75 0.1% 6.9% 0.0% 0.0% 0.0% 0.1% 6.9% 0.0% 0.0% 0.0%

14.25 0.0% 5.6% 0.0% 0.0% 0.0% 0.0% 5.6% 0.0% 0.0% 0.0%

15.75 0.0% 5.2% 0.0% 0.0% 0.0% 0.0% 5.2% 0.0% 0.0% 0.0%

17.25 0.0% 1.5% 5.3% 0.0% 0.0% 0.0% 1.5% 5.3% 0.0% 0.0%

18.75 0.0% 0.0% 6.5% 0.0% 0.0% 0.0% 0.0% 6.5% 0.0% 0.0%

20.25 0.0% 0.0% 6.4% 0.0% 0.0% 0.0% 0.0% 6.4% 0.0% 0.0%

21.75 0.0% 0.0% 2.9% 4.1% 0.0% 0.0% 0.0% 2.9% 4.1% 0.0%

23.25 0.0% 0.0% 0.0% 15.8% 20.2% 0.0% 0.0% 0.0% 15.8% 20.2%

Separating Distance: 5-8 Meters

0.75 9.5% 7.4% 4.9% 0.7% 2.1% 9.5% 7.4% 4.9% 0.7% 2.1%

2.25 35.8% 30.2% 31.5% 21.0% 22.7% 35.8% 30.2% 31.5% 21.0% 22.7%

3.75 34.9% 37.6% 31.0% 37.0% 39.2% 34.9% 37.6% 31.0% 37.0% 39.2%

5.25 14.8% 16.3% 23.4% 26.1% 22.7% 14.8% 16.3% 23.4% 26.1% 22.7%

6.75 2.2% 1.6% 1.1% 2.2% 3.1% 2.2% 1.6% 1.1% 2.2% 3.1%

8.25 1.0% 0.0% 0.0% 0.0% 0.0% 1.0% 0.0% 0.0% 0.0% 0.0%

9.75 1.0% 0.0% 0.0% 0.0% 0.0% 1.0% 0.0% 0.0% 0.0% 0.0%

11.25 0.7% 0.0% 0.0% 0.0% 0.0% 0.7% 0.0% 0.0% 0.0% 0.0%

12.75 0.0% 2.3% 0.0% 0.0% 0.0% 0.0% 2.3% 0.0% 0.0% 0.0%

14.25 0.0% 2.3% 0.0% 0.0% 0.0% 0.0% 2.3% 0.0% 0.0% 0.0%
292

Left Side Impact Right Side Impact

Delta-V Approaching Vehicle Speed (mph) Approaching Vehicle Speed (mph)

(mph) [10, 25) [25, 35) [35, 45) [45, 55) 55+ [10, 25) [25, 35) [35, 45) [45, 55) 55+

15.75 0.0% 1.9% 0.0% 0.0% 0.0% 0.0% 1.9% 0.0% 0.0% 0.0%

17.25 0.0% 0.4% 3.8% 0.0% 0.0% 0.0% 0.4% 3.8% 0.0% 0.0%

18.75 0.0% 0.0% 2.2% 0.0% 0.0% 0.0% 0.0% 2.2% 0.0% 0.0%

20.25 0.0% 0.0% 1.6% 0.0% 0.0% 0.0% 0.0% 1.6% 0.0% 0.0%

21.75 0.0% 0.0% 0.5% 0.7% 0.0% 0.0% 0.0% 0.5% 0.7% 0.0%

23.25 0.0% 0.0% 0.0% 12.3% 10.3% 0.0% 0.0% 0.0% 12.3% 10.3%

*equivalent to half of the crash impact speed

Source: SIM simulation output
293

Table XIII-4 PCP-M Scenario - Delta-V* Distribution by Approaching Vehicle Speed

Baseline Treatment

Delta-V Approaching Vehicle Speed (mph) Approaching Vehicle Speed (mph)

(mph) [10, 25) [25, 35) [35, 45) [45, 55) 55+ [10, 25) [25, 35) [35, 45) [45, 55) 55+

Driver Vehicle Speed [10, 25)

0.75 0.5% 0.5% 0.2% 0.1% 0.0% 4.4% 1.6% 0.7% 0.4% 0.0%

2.25 1.8% 1.8% 1.6% 1.4% 0.9% 13.6% 8.8% 5.6% 4.5% 2.5%

3.75 5.4% 5.4% 5.6% 5.4% 5.0% 21.2% 20.2% 16.5% 15.1% 12.2%

5.25 18.2% 18.0% 18.4% 18.7% 18.7% 22.4% 24.3% 24.1% 23.6% 21.3%

6.75 20.5% 20.6% 20.9% 20.9% 21.1% 18.1% 20.9% 24.0% 25.0% 25.2%

8.25 20.3% 20.6% 20.1% 20.1% 20.4% 12.3% 14.4% 17.4% 19.0% 22.8%

9.75 18.8% 18.8% 18.5% 18.7% 19.1% 6.4% 7.6% 9.1% 9.6% 12.7%

11.25 14.1% 14.0% 14.1% 14.1% 14.2% 1.7% 2.2% 2.5% 2.8% 3.2%

12.75 0.5% 0.5% 0.5% 0.5% 0.5% 0.0% 0.0% 0.1% 0.1% 0.1%

14.25 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

15.75 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

17.25 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

18.75 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

20.25 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

21.75 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

23.25 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

Driver Vehicle Speed [25, 35)

0.75 0.1% 0.0% 0.0% 0.0% 0.0% 0.6% 0.0% 0.0% 0.0% 0.0%

2.25 0.2% 0.0% 0.0% 0.0% 0.0% 2.8% 0.1% 0.0% 0.0% 0.0%

3.75 0.6% 0.2% 0.0% 0.0% 0.0% 6.5% 0.9% 0.1% 0.0% 0.0%

5.25 1.2% 1.0% 0.5% 0.1% 0.0% 11.7% 4.8% 1.4% 0.5% 0.0%

6.75 2.3% 2.3% 1.8% 1.2% 0.3% 16.0% 12.8% 6.9% 4.2% 0.9%

8.25 4.4% 4.7% 4.4% 4.1% 2.9% 17.7% 20.6% 17.1% 14.0% 7.7%

9.75 8.4% 8.4% 8.4% 8.4% 8.0% 16.9% 23.2% 25.5% 25.1% 21.7%

11.25 15.2% 15.4% 15.7% 15.8% 16.5% 14.2% 19.1% 24.1% 27.8% 30.3%

12.75 26.7% 26.6% 27.2% 27.6% 28.3% 9.1% 12.0% 15.8% 18.1% 24.9%

14.25 22.8% 23.1% 23.3% 23.9% 24.9% 3.6% 5.4% 7.6% 8.5% 11.9%

15.75 15.4% 15.7% 16.0% 16.2% 16.3% 0.8% 1.2% 1.4% 1.8% 2.6%

17.25 2.6% 2.5% 2.7% 2.7% 2.7% 0.0% 0.0% 0.0% 0.0% 0.0%

18.75 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

20.25 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

21.75 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

23.25 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

Driver Vehicle Speed [35, 45)

0.75 0.0% 0.0% 0.0% 0.0% 0.0% 0.1% 0.0% 0.0% 0.0% 0.0%

2.25 0.1% 0.0% 0.0% 0.0% 0.0% 0.5% 0.0% 0.0% 0.0% 0.0%

3.75 0.2% 0.0% 0.0% 0.0% 0.0% 1.6% 0.0% 0.0% 0.0% 0.0%

5.25 0.5% 0.0% 0.0% 0.0% 0.0% 3.8% 0.1% 0.0% 0.0% 0.0%

6.75 1.1% 0.2% 0.0% 0.0% 0.0% 6.8% 0.8% 0.0% 0.0% 0.0%

8.25 1.9% 1.1% 0.3% 0.0% 0.0% 10.9% 3.2% 0.8% 0.1% 0.0%

9.75 2.8% 2.7% 1.4% 0.7% 0.0% 14.5% 9.1% 3.5% 1.3% 0.0%

11.25 4.8% 4.6% 4.0% 3.1% 1.0% 16.0% 16.0% 10.5% 6.6% 2.2%

12.75 7.1% 7.6% 7.6% 7.0% 4.7% 14.2% 21.3% 19.1% 16.4% 9.1%

14.25 11.1% 11.4% 11.9% 11.9% 11.2% 13.0% 21.0% 24.7% 24.2% 21.4%

15.75 16.2% 17.2% 17.8% 18.1% 19.4% 9.6% 15.2% 20.7% 25.8% 27.4%
294

Baseline Treatment

Delta-V Approaching Vehicle Speed (mph) Approaching Vehicle Speed (mph)

(mph) [10, 25) [25, 35) [35, 45) [45, 55) 55+ [10, 25) [25, 35) [35, 45) [45, 55) 55+

17.25 22.0% 22.2% 23.3% 24.1% 25.7% 5.6% 8.7% 12.9% 16.4% 24.0%

18.75 18.5% 18.7% 19.3% 20.1% 21.4% 2.6% 3.9% 6.1% 7.3% 12.6%

20.25 11.4% 11.7% 11.7% 12.2% 13.3% 0.8% 1.0% 1.7% 1.9% 3.2%

21.75 2.4% 2.5% 2.6% 2.8% 3.2% 0.0% 0.0% 0.0% 0.0% 0.0%

23.25 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

Driver Vehicle Speed [45, 55)

0.75 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

2.25 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

3.75 0.0% 0.0% 0.0% 0.0% 0.0% 0.2% 0.0% 0.0% 0.0% 0.0%

5.25 0.1% 0.0% 0.0% 0.0% 0.0% 0.7% 0.0% 0.0% 0.0% 0.0%

6.75 0.4% 0.0% 0.0% 0.0% 0.0% 1.9% 0.0% 0.0% 0.0% 0.0%

8.25 0.6% 0.0% 0.0% 0.0% 0.0% 4.1% 0.0% 0.0% 0.0% 0.0%

9.75 1.3% 0.2% 0.0% 0.0% 0.0% 6.6% 0.2% 0.0% 0.0% 0.0%

11.25 2.1% 0.8% 0.1% 0.0% 0.0% 9.8% 1.8% 0.1% 0.0% 0.0%

12.75 3.3% 2.3% 0.8% 0.2% 0.0% 12.7% 5.1% 1.3% 0.4% 0.0%

14.25 4.8% 4.6% 2.8% 1.5% 0.1% 14.6% 10.9% 5.1% 2.4% 0.2%

15.75 7.0% 7.0% 6.2% 4.8% 1.9% 14.0% 17.8% 10.9% 6.8% 2.6%

17.25 9.5% 9.9% 9.7% 9.6% 6.8% 11.9% 20.0% 18.8% 15.6% 8.2%

18.75 12.9% 13.6% 14.4% 14.9% 14.3% 9.9% 17.7% 23.5% 22.4% 18.4%

20.25 16.4% 17.2% 18.7% 19.6% 21.4% 6.9% 13.2% 19.5% 25.2% 27.5%

21.75 18.6% 19.4% 20.9% 22.0% 24.2% 4.0% 8.0% 12.4% 16.4% 24.6%

23.25 23.0% 25.0% 26.4% 27.4% 31.4% 2.8% 5.2% 8.2% 10.7% 18.5%

Driver Vehicle Traveling Speed 55+

0.75 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

2.25 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

3.75 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

5.25 0.0% 0.0% 0.0% 0.0% 0.0% 0.1% 0.0% 0.0% 0.0% 0.0%

6.75 0.1% 0.0% 0.0% 0.0% 0.0% 0.3% 0.0% 0.0% 0.0% 0.0%

8.25 0.2% 0.0% 0.0% 0.0% 0.0% 0.9% 0.0% 0.0% 0.0% 0.0%

9.75 0.5% 0.0% 0.0% 0.0% 0.0% 2.2% 0.0% 0.0% 0.0% 0.0%

11.25 0.8% 0.0% 0.0% 0.0% 0.0% 3.6% 0.0% 0.0% 0.0% 0.0%

12.75 1.5% 0.1% 0.0% 0.0% 0.0% 5.9% 0.1% 0.0% 0.0% 0.0%

14.25 2.4% 0.5% 0.0% 0.0% 0.0% 8.5% 0.5% 0.1% 0.0% 0.0%

15.75 3.6% 1.7% 0.3% 0.0% 0.0% 10.5% 2.4% 0.2% 0.0% 0.0%

17.25 5.0% 3.8% 1.6% 0.5% 0.0% 12.5% 5.7% 1.6% 0.1% 0.0%

18.75 6.5% 6.6% 4.2% 2.4% 0.4% 13.6% 11.7% 4.3% 1.6% 0.0%

20.25 8.8% 9.2% 8.3% 6.6% 2.6% 11.9% 16.8% 10.4% 5.3% 0.4%

21.75 10.7% 11.4% 12.1% 11.4% 7.9% 9.9% 19.8% 18.2% 13.5% 2.6%

23.25 60.0% 66.7% 73.5% 79.2% 89.2% 20.2% 42.9% 65.2% 79.5% 97.0%

*equivalent to half of the crash impact speed

Source: SIM simulation output
295

Table XIII-5 Passenger Vehicle Fleet Communication Rates by Technology 

Implementation Scenarios

Year of 

Implementation Calendar Year Scenario 1 Scenario 2 Scenario 3

1 2020 0.06% 0.03% 0.00%

2 2021 0.51% 0.26% 0.02%

3 2022 2.46% 0.95% 0.09%

4 2023 5.69% 2.20% 0.22%

5 2024 11.01% 4.08% 0.39%

6 2025 17.45% 6.66% 0.61%

7 2026 24.60% 10.02% 0.86%

8 2027 29.92% 14.19% 1.15%

9 2028 35.45% 18.88% 1.46%

10 2029 41.09% 23.99% 1.81%

11 2030 46.77% 29.46% 2.17%

12 2031 52.36% 35.17% 2.53%

13 2032 57.80% 41.02% 2.91%

14 2033 62.97% 46.90% 3.28%

15 2034 67.86% 52.75% 3.64%

16 2035 72.38% 58.44% 3.98%

17 2036 76.51% 63.87% 4.30%

18 2037 80.19% 68.92% 4.60%

19 2038 83.42% 73.51% 4.86%

20 2039 86.16% 77.59% 5.09%

21 2040 88.47% 81.13% 5.28%

22 2041 90.42% 84.16% 5.45%

23 2042 92.01% 86.70% 5.57%

24 2043 93.34% 88.83% 5.68%

25 2044 94.47% 90.62% 5.77%

26 2045 95.37% 92.10% 5.85%

27 2046 96.14% 93.35% 5.91%

28 2047 96.85% 94.45% 5.97%

29 2048 97.48% 95.43% 6.02%

30 2049 98.06% 96.29% 6.06%

31 2050 98.51% 97.02% 6.10%

32 2051 98.90% 97.63% 6.14%

33 2052 99.19% 98.16% 6.17%

34 2053 99.42% 98.62% 6.19%

35 2054 99.63% 99.00% 6.21%

36 2055 99.78% 99.32% 6.23%

37 2056 99.91% 99.57% 6.24%

38 2057 99.97% 99.73% 6.25%

39 2058 100.00% 99.84% 6.25%

40 2059 100.00% 99.91% 6.25%
296

Table XIII-6 Passenger Vehicle Fleet Communication Rate by Vehicle Types* and 

Technology Implementation Scenarios

Year of Calendar Scenario 1 Scenario 2 Scenario 3

Implementation Year PCs LTVs PCs LTVs PCs LTVs

1 2020 0.03% 0.03% 0.02% 0.01% 0.00% 0.00%

2 2021 0.28% 0.23% 0.14% 0.12% 0.01% 0.01%

3 2022 1.34% 1.12% 0.52% 0.43% 0.05% 0.04%

4 2023 3.10% 2.58% 1.20% 1.00% 0.12% 0.10%

5 2024 6.01% 5.00% 2.23% 1.85% 0.21% 0.18%

6 2025 9.54% 7.91% 3.64% 3.02% 0.33% 0.28%

7 2026 13.47% 11.12% 5.48% 4.54% 0.47% 0.39%

8 2027 16.41% 13.51% 7.76% 6.43% 0.63% 0.52%

9 2028 19.47% 15.99% 10.33% 8.55% 0.80% 0.66%

10 2029 22.59% 18.50% 13.14% 10.85% 0.99% 0.82%

11 2030 25.74% 21.02% 16.15% 13.31% 1.19% 0.98%

12 2031 28.85% 23.51% 19.30% 15.87% 1.39% 1.14%

13 2032 31.87% 25.93% 22.54% 18.48% 1.60% 1.31%

14 2033 34.74% 28.23% 25.81% 21.09% 1.81% 1.47%

15 2034 37.44% 30.41% 29.07% 23.68% 2.01% 1.63%

16 2035 39.94% 32.44% 32.25% 26.19% 2.20% 1.78%

17 2036 42.20% 34.31% 35.28% 28.59% 2.38% 1.92%

18 2037 44.19% 36.01% 38.10% 30.82% 2.55% 2.05%

19 2038 45.90% 37.52% 40.64% 32.87% 2.69% 2.17%

20 2039 47.32% 38.84% 42.88% 34.71% 2.81% 2.28%

21 2040 48.48% 39.99% 44.80% 36.33% 2.91% 2.37%

22 2041 49.43% 40.99% 46.41% 37.75% 3.00% 2.45%

23 2042 50.09% 41.93% 47.64% 39.06% 3.05% 2.52%

24 2043 50.59% 42.75% 48.62% 40.21% 3.10% 2.58%

25 2044 50.99% 43.48% 49.39% 41.23% 3.13% 2.64%

26 2045 51.26% 44.11% 49.99% 42.11% 3.16% 2.69%

27 2046 51.46% 44.68% 50.45% 42.90% 3.18% 2.73%

28 2047 51.63% 45.22% 50.83% 43.62% 3.20% 2.77%

29 2048 51.77% 45.71% 51.14% 44.29% 3.21% 2.81%

30 2049 51.89% 46.17% 51.39% 44.90% 3.22% 2.84%

31 2050 51.95% 46.57% 51.57% 45.45% 3.23% 2.87%

32 2051 51.98% 46.92% 51.69% 45.94% 3.24% 2.90%

33 2052 51.97% 47.21% 51.77% 46.39% 3.24% 2.93%

34 2053 51.95% 47.47% 51.82% 46.80% 3.24% 2.95%

35 2054 51.93% 47.70% 51.85% 47.15% 3.24% 2.97%

36 2055 51.89% 47.89% 51.86% 47.46% 3.24% 2.99%

37 2056 51.85% 48.05% 51.84% 47.73% 3.24% 3.00%

38 2057 50.40% 49.57% 51.80% 47.93% 3.24% 3.01%

39 2058 50.36% 49.64% 51.75% 48.09% 3.23% 3.02%

40 2059 50.33% 49.67% 51.70% 48.21% 3.23% 3.02%

*The communication rates are used to discern the portion of benefit that would attributed to a specific vehicle type –

a process for deriving the benefit for a specific model year of vehicles in order to measure cost-effectiveness.
297

Table XIII-7 Preliminary Annual Benefits* Estimates of IMA and LTA 

Scenario 1 

Calendar Crash Prevented Fatalities Eliminated MAIS 1-5 Injuries PDOV

Year Year Low High Low High Low High Low High

1 2020 248 355 0.47 0.65 115 162 307 437

2 2021 2,104 3,020 3.96 5.52 975 1,377 2,607 3,714

3 2022 10,148 14,569 19.11 26.64 4,704 6,642 12,574 17,913

4 2023 23,472 33,698 44.21 61.62 10,879 15,364 29,083 41,433

5 2024 45,418 65,205 85.55 119.24 21,051 29,728 56,274 80,172

6 2025 71,983 103,344 135.59 188.98 33,365 47,117 89,190 127,066

7 2026 101,478 145,689 191.14 266.42 47,036 66,423 125,735 179,131

8 2027 123,424 177,195 232.48 324.03 57,208 80,787 152,927 217,869

9 2028 146,236 209,946 275.45 383.92 67,781 95,719 181,191 258,137

10 2029 169,501 243,347 319.27 445.00 78,565 110,948 210,018 299,206

11 2030 192,932 276,986 363.40 506.52 89,425 126,284 239,050 340,567

12 2031 215,991 310,092 406.84 567.06 100,113 141,378 267,621 381,271

13 2032 238,432 342,309 449.11 625.97 110,515 156,066 295,426 420,884

14 2033 259,759 372,927 489.28 681.97 120,400 170,026 321,851 458,531

15 2034 279,931 401,887 527.27 734.92 129,750 183,229 346,845 494,138

16 2035 298,576 428,656 562.39 783.88 138,392 195,434 369,947 527,052

17 2036 315,613 453,115 594.48 828.60 146,289 206,585 391,056 557,125

18 2037 330,793 474,909 623.08 868.46 153,325 216,522 409,866 583,922

19 2038 344,118 494,038 648.17 903.44 159,501 225,243 426,375 607,442

20 2039 355,420 510,265 669.46 933.11 164,740 232,641 440,379 627,394

21 2040 364,949 523,946 687.41 958.13 169,156 238,879 452,186 644,215

22 2041 372,993 535,494 702.56 979.25 172,885 244,144 462,153 658,414

23 2042 379,552 544,911 714.92 996.47 175,925 248,437 470,280 669,992

24 2043 385,039 552,787 725.25 1010.87 178,468 252,028 477,078 679,677

25 2044 389,700 559,480 734.03 1023.11 180,629 255,079 482,853 687,905

26 2045 393,413 564,810 741.02 1032.86 182,349 257,509 487,453 694,459

27 2046 396,589 569,370 747.01 1041.20 183,822 259,589 491,389 700,066

28 2047 399,518 573,575 752.52 1048.89 185,179 261,506 495,018 705,236

29 2048 402,117 577,306 757.42 1055.71 186,384 263,207 498,238 709,823

30 2049 404,509 580,741 761.93 1061.99 187,493 264,773 501,202 714,046

31 2050 406,366 583,406 765.42 1066.86 188,353 265,988 503,502 717,323

32 2051 407,974 585,715 768.45 1071.09 189,099 267,041 505,496 720,163

33 2052 409,171 587,433 770.71 1074.23 189,653 267,824 506,978 722,275

34 2053 410,119 588,795 772.49 1076.72 190,093 268,445 508,154 723,950

35 2054 410,986 590,039 774.13 1078.99 190,495 269,012 509,227 725,479

36 2055 411,604 590,927 775.29 1080.62 190,781 269,417 509,994 726,571

37 2056 412,141 591,697 776.30 1082.03 191,030 269,768 510,658 727,518

38 2057 412,388 592,052 776.77 1082.68 191,145 269,930 510,965 727,955

39 2058 412,512 592,230 777.00 1083.00 191,202 270,011 511,118 728,173

*Benefits are defined as potential lives saved, injuries prevented and the reduction in number of property-damaged 

vehicles
298

Table XIII-8 Preliminary Annual Benefits* Estimates of IMA and LTA 

Scenario 2

Calendar Crash Prevented Fatalities Eliminated MAIS 1-5 Injuries PDOV

Year Year Low High Low High Low High Low High

1 2020 124 178 0.23 0.32 57 81 153 218

2 2021 1,073 1,540 2.02 2.82 497 702 1,329 1,893

3 2022 3,919 5,626 7.38 10.29 1,816 2,565 4,856 6,918

4 2023 9,075 13,029 17.09 23.83 4,206 5,940 11,245 16,020

5 2024 16,830 24,163 31.70 44.19 7,801 11,016 20,854 29,709

6 2025 27,473 39,443 51.75 72.13 12,734 17,983 34,040 48,496

7 2026 41,334 59,341 77.86 108.52 19,158 27,055 51,214 72,963

8 2027 58,535 84,037 110.26 153.68 27,132 38,315 72,528 103,328

9 2028 77,882 111,813 146.70 204.47 36,099 50,978 96,499 137,479

10 2029 98,962 142,076 186.40 259.81 45,869 64,776 122,617 174,689

11 2030 121,526 174,471 228.90 319.05 56,328 79,545 150,575 214,520

12 2031 145,080 208,287 273.27 380.89 67,246 94,963 179,760 256,098

13 2032 169,212 242,933 318.73 444.25 78,431 110,759 209,661 298,697

14 2033 193,468 277,756 364.41 507.93 89,674 126,635 239,714 341,513

15 2034 217,600 312,401 409.87 571.28 100,859 142,431 269,615 384,111

16 2035 241,072 346,099 454.08 632.91 111,738 157,794 298,697 425,544

17 2036 263,471 378,257 496.27 691.71 122,121 172,456 326,451 465,084

18 2037 284,303 408,165 535.51 746.40 131,776 186,092 352,263 501,857

19 2038 303,238 435,348 571.17 796.11 140,553 198,485 375,723 535,280

20 2039 320,068 459,511 602.87 840.30 148,354 209,502 396,576 564,989

21 2040 334,671 480,476 630.38 878.64 155,122 219,060 414,670 590,767

22 2041 347,170 498,421 653.92 911.45 160,916 227,241 430,157 612,830

23 2042 357,648 513,463 673.66 938.96 165,772 234,100 443,139 631,326

24 2043 366,434 526,078 690.21 962.03 169,845 239,851 454,026 646,836

25 2044 373,818 536,679 704.12 981.41 173,267 244,684 463,175 659,870

26 2045 379,924 545,444 715.62 997.44 176,097 248,680 470,740 670,647

27 2046 385,080 552,847 725.33 1010.98 178,487 252,055 477,129 679,750

28 2047 389,618 559,361 733.88 1022.89 180,590 255,025 482,751 687,759

29 2048 393,660 565,165 741.49 1033.51 182,464 257,672 487,760 694,895

30 2049 397,208 570,258 748.17 1042.82 184,108 259,994 492,156 701,158

31 2050 400,219 574,582 753.85 1050.73 185,504 261,965 495,887 706,473

32 2051 402,735 578,194 758.59 1057.33 186,671 263,612 499,005 710,915

33 2052 404,922 581,333 762.70 1063.07 187,684 265,043 501,713 714,775

34 2053 406,819 584,057 766.28 1068.05 188,563 266,285 504,065 718,124

35 2054 408,387 586,308 769.23 1072.17 189,290 267,311 506,007 720,891

36 2055 409,707 588,203 771.72 1075.64 189,902 268,175 507,642 723,221

37 2056 410,738 589,683 773.66 1078.34 190,380 268,850 508,920 725,042

38 2057 411,398 590,631 774.90 1080.08 190,686 269,282 509,738 726,207

39 2058 411,852 591,282 775.76 1081.27 190,896 269,579 510,300 727,008

*Benefits are defined as potential lives saved, injuries prevented and the reduction in number of property-damaged 

vehicles
299

Table XIII-9 Preliminary Annual Benefits* Estimates of IMA and LTA

Scenario 3

Calendar Crash Prevented Fatalities 

Eliminated

MAIS 1-5 Injuries PDOV

Year Year Low High Low High Low High Low High

1 2020 0 0 0.00 0.00 0 0 0 0

2 2021 83 118 0.16 0.22 38 54 102 146

3 2022 371 533 0.70 0.97 172 243 460 655

4 2023 908 1,303 1.71 2.38 421 594 1,124 1,602

5 2024 1,609 2,310 3.03 4.22 746 1,053 1,993 2,840

6 2025 2,516 3,613 4.74 6.61 1,166 1,647 3,118 4,442

7 2026 3,548 5,093 6.68 9.31 1,644 2,322 4,396 6,262

8 2027 4,744 6,811 8.94 12.45 2,199 3,105 5,878 8,374

9 2028 6,023 8,647 11.34 15.81 2,792 3,942 7,462 10,631

10 2029 7,466 10,719 14.06 19.60 3,461 4,887 9,251 13,180

11 2030 8,952 12,851 16.86 23.50 4,149 5,859 11,091 15,801

12 2031 10,437 14,983 19.66 27.40 4,837 6,831 12,931 18,423

13 2032 12,004 17,234 22.61 31.52 5,564 7,857 14,874 21,190

14 2033 13,530 19,425 25.49 35.52 6,271 8,856 16,765 23,884

15 2034 15,015 21,557 28.28 39.42 6,960 9,828 18,605 26,506

16 2035 16,418 23,571 30.92 43.10 7,610 10,746 20,343 28,981

17 2036 17,738 25,466 33.41 46.57 8,222 11,610 21,978 31,311

18 2037 18,976 27,243 35.74 49.82 8,795 12,421 23,511 33,496

19 2038 20,048 28,782 37.76 52.63 9,292 13,123 24,840 35,389

20 2039 20,997 30,145 39.55 55.12 9,732 13,744 26,016 37,064

21 2040 21,781 31,270 41.03 57.18 10,095 14,257 26,987 38,448

22 2041 22,482 32,277 42.35 59.02 10,421 14,716 27,856 39,685

23 2042 22,977 32,987 43.28 60.32 10,650 15,040 28,469 40,559

24 2043 23,431 33,639 44.13 61.51 10,860 15,337 29,032 41,360

25 2044 23,802 34,172 44.83 62.49 11,032 15,580 29,492 42,016

26 2045 24,132 34,645 45.45 63.36 11,185 15,796 29,900 42,598

27 2046 24,379 35,001 45.92 64.01 11,300 15,958 30,207 43,035

28 2047 24,627 35,356 46.39 64.66 11,415 16,120 30,514 43,472

29 2048 24,833 35,652 46.78 65.20 11,510 16,255 30,769 43,836

30 2049 24,998 35,889 47.09 65.63 11,587 16,363 30,974 44,127

31 2050 25,163 36,126 47.40 66.06 11,663 16,471 31,178 44,419

32 2051 25,328 36,363 47.71 66.50 11,740 16,579 31,383 44,710

33 2052 25,452 36,541 47.94 66.82 11,797 16,660 31,536 44,928

34 2053 25,534 36,659 48.10 67.04 11,835 16,714 31,638 45,074

35 2054 25,617 36,777 48.25 67.25 11,874 16,768 31,740 45,220

36 2055 25,700 36,896 48.41 67.47 11,912 16,822 31,843 45,365

37 2056 25,741 36,955 48.48 67.58 11,931 16,849 31,894 45,438

38 2057 25,782 37,014 48.56 67.69 11,950 16,876 31,945 45,511

39 2058 25,782 37,014 48.56 67.69 11,950 16,876 31,945 45,511

*Benefits are defined as potential lives saved, injuries prevented and the reduction in number of property-damaged 

vehicles
300

XIV. Appendix B: List of Policy, Standards and Research Needs

A. Policy needs

Policy Need IV-1 Road Side Equipment Authority....................................................................................42

Policy Need IV-2 V2V Device Software Updates......................................................................................59

B. Standards needs

Standards Need V-1 SAE Standards Maturity............................................................................................79

C. Research needs

Research Need V-1 Spectrum Sharing Interference ...................................................................................92

Research Need V-2 Impact of Software Implementation on DSRC Device Performance .......................103

Research Need V-3 DSRC Data Communication System Performance Measures..................................104

Research Need V-4 Development of Safety Application Test Metrics and Procedures...........................104

Research Need V-5 BSM Congestion Sensitivity.....................................................................................112

Research Need V-6 Relative Positioning Performance Test.....................................................................113

Research Need V-7 Vehicle and Receiver Positioning Biases .................................................................114

Research Need VI-1 False Positive Mitigation.........................................................................................127

Research Need VI-2 Safety Application Performance Measure Rationale...............................................127

Research Need VI-3 Practicability of Non-Ideal Driving Condition Testing...........................................128

Research Need VI-4 Fused and Non-Fused V2V Safety Application Test Procedures............................128

Research Need VI-5 Performance and Test Metric Validation.................................................................128

Research Need VI-6 DVI Minimum Performance Requirements ............................................................129

Research Need VI-7 Compliance Specifications and Requirements........................................................131

Research Need VII-1 Consumer Acceptance............................................................................................138

Research Need VIII-1 V2V Location Tracking via BSM.........................................................................154

Research Need VIII-2 V2V Identification Capabilities............................................................................155

Research Need VIII-3 V2V Inventory of Privacy Controls......................................................................156

Research Need VIII-4 V2V Privacy Risk Assessment .............................................................................157

Research Need IX-1 Misbehavior Authority ............................................................................................174

Research Need IX-2 Cryptographic flexibility .........................................................................................184

Research Need IX-3 Independent Security Design Assessment...............................................................189
301

XV. Appendix C: List of Tables, Figures and Equations

A. Tables

Table III-1 37 Pre-Crash Scenario Typology................................................................................ 16

Table III-2 Societal Cost and Ranking of 22 Target Light-Vehicle Pre-Crash Scenarios............ 20

Table III-3 Light-Vehicle 2004-2008 GES Averages for V2V Target Pre-Crash Scenarios....... 22

Table III-4 Groups of Target Light-Vehicle V2V Pre-Crash Scenarios and Associated 

Societal Cost ................................................................................................................................. 23

Table III-5 Aftermarket Safety Device Types.............................................................................. 31

Table V-1 Contents of BSM Part I ............................................................................................... 75

Table V-2 Contents of BSM Part II.............................................................................................. 76

Table V-3 Cooperative System Standards for V2V Communications......................................... 80

Table V-4 Contents of Draft J2495.1 Standard ............................................................................ 82

Table V-5 ITS V2X Cooperative System Standards Latest Publication and Current Status........ 86

Table V-6 Performance requirements used in V2V research ..................................................... 100

Table V-7 Collision Avoidance Sensor Summary...................................................................... 105

Table VI-1 V2V Safety Applications ......................................................................................... 120

Table VII-1 Comparison of Findings between Driver Acceptance Clinics and Safety Pilot Model 

Deployment during the First 6 Months....................................................................................... 142

Table IX-1 Security Approach Alternatives,............................................................................... 160

Table IX-2 V2V Communication Security Research ................................................................. 177

Table IX-3 VIIC Concept of Security Certificate Management System Functional Area 

Distribution ................................................................................................................................. 205

Table XI-1 Summary of Preliminary Costs per Vehicle............................................................. 218

Table XI-2 Summary of Likely Costs in Year 1 for New Vehicles (2012 dollars).................... 219

Table XI-3 Likely Supplier Costs to OEM................................................................................. 220

Table XI-4 Preliminary Consumer Costs (for just supplier parts) Per Vehicle (2012 dollars)... 221

Table XI-5 Preliminary Estimates of Display Costs (2012 dollars) ........................................... 222

Table XI-6 Preliminary Installation Cost Estimates (2012 dollars)............................................ 223

Table XI-7 Estimated Percentage of GPS in the New Vehicle Fleet.......................................... 226

Table XI-8 Summary of Cost Estimates in Year 1 for New Vehicles........................................ 226

Table XI-9 Estimated Consumer Cost of Aftermarket Equipment – Retrofit Device 

(2012 dollars).............................................................................................................................. 228

Table XI-10 Estimated Consumer Cost of Aftermarket Equipment – Self-Contained Device 

(2012 dollars).............................................................................................................................. 228

Table XI-11 Estimated Consumer Cost of Aftermarket Equipment – Vehicle Awareness 

Device (2012 dollars).................................................................................................................. 229

Table XI-12 Aftermarket Consumer Cost Estimates for Year 1 (2012 dollars)......................... 230
302

Table XI-13 V2V Technology Sales Assumptions in New Vehicles (Millions of Vehicle)...... 232

Table XI-14 Estimated Miles per Gallon (MPG) Values ........................................................... 235

Table XI-15 Summary of Incremental Vehicle Weight Due to V2V Equipment....................... 236

Table XI-16 Impact of weight increase on fuel economy over the lifetime of the model year 

vehicle (per vehicle cost for 3.45 lb. increase) ........................................................................... 236

Table XI-17 Cost Assumptions................................................................................................... 246

Table XI-18 OBE Subcomponent Cost Estimate........................................................................ 246

Table XI-19 Total Estimated Costs - Cellular ............................................................................ 247

Table XI-20 Total Estimated Costs - Hybrid.............................................................................. 247

Table XI-21 Total Estimated Costs – DSRC.............................................................................. 248

Table XI-22 Road Side Equipment Cost Estimates.................................................................... 248

Table XI-23 Communication Data Cost Estimate per Vehicle................................................... 249

Table XI-24 Total Communication Cost Estimates per Year by Scenario................................. 250

Table XI-25 Total Cost Estimates Comparing Full CRL to No CRL in Millions 

(2012 dollars).............................................................................................................................. 251

Table XI-26 Undiscounted Cost Estimates per Component for Selected Years, Scenario 1, 

Two Year Downloads................................................................................................................. 255

Table XI-27 Undiscounted Cost Estimate of PCA for Selected Years, Scenario 1, Two Year 

Downloads .................................................................................................................................. 256

Table XII-1 Safety Target Population for FCW, LCW, IMA, and LTA - Passenger Vehicles.. 265

Table XII-2 Breakdown of Drivers in IMA Study...................................................................... 273

Table XII-3 Probabilities of MAIS Injuries and Injury Reduction Effectiveness...................... 275

Table XII-4 Percent of Crash Distribution* by Approaching Vehicle Traveling Speed (pi) ..... 276

Table XII-5 Percent of Impact Location*................................................................................... 276

Table XII-6 SIM Estimated Initial Effectiveness ( and ) ............................................. 277

Table XII-7 Weighted IMA Effectiveness (Ea) for PCP-S Crash Scenario................................ 278

Table XII-8 Percent of Crash Distribution* by Approaching Vehicle Traveling Speed (pi) ..... 278

Table XII-9 SIM Estimated Initial Effectiveness (Ea)................................................................ 279

Table XII-10 Derived Average Delta-V (mph) by Simulated Crash Conditions ....................... 280

Table XII-11 Traveling Speed Distribution*.............................................................................. 281

Table XII-12 Delta-V for an Average PCP-S Crash................................................................... 281

Table XII-13 Derived Average Delta-V (mph) by Simulated Crash Conditions ....................... 281

Table XII-14 Traveling Speed Distribution*.............................................................................. 282

Table XII-15 Delta-V for an Average PCP-M Crash ................................................................. 282

Table XII-16 Effectiveness for LTAP-M and LTAP-S .............................................................. 284

Table XII-17 System Effectiveness............................................................................................ 284

Table XII-18 System Effectiveness of IMA and LTA................................................................ 284

Table XII-19 Non-Discounted Annual Preliminary Maximum Estimated Benefit Summary ... 287

Table XIII-1 RSE Data Cost per Vehicle ................................................................................... 288
303

Table XIII-2 PCP-S Scenario - Delta-V* Distribution by Approaching Vehicle Traveling 

Speed Baseline (Without V2V) .................................................................................................. 289

Table XIII-3 PCP-S Scenario - Delta-V* Distribution by Approaching Vehicle Traveling 

Speed Treatment (With V2V)..................................................................................................... 291

Table XIII-4 PCP-M Scenario - Delta-V* Distribution by Approaching Vehicle Speed........... 293

Table XIII-5 Passenger Vehicle Fleet Communication Rates by Technology Implementation 

Scenarios..................................................................................................................................... 295

Table XIII-6 Passenger Vehicle Fleet Communication Rate by Vehicle Types* and 

Technology Implementation Scenarios....................................................................................... 296

Table XIII-7 Preliminary Annual Benefits* Estimates of IMA and LTA.................................. 297

Table XIII-8 Preliminary Annual Benefits* Estimates of IMA and LTA.................................. 298

Table XIII-9 Preliminary Annual Benefits* Estimates of IMA and LTA.................................. 299

B. Figures

Figure II-1 Visual Representation of V2V Communication.........................................................................8

Figure III-1 Target Unimpaired Light Vehicle Crashes Potentially Addressed by V2V............................17

Figure III-2 22 Target Light-Vehicle Pre-Crash Scenario Crash Statistics ................................................18

Figure III-3 V2V Light-Vehicle Target Crashes Breakdown .....................................................................19

Figure III-4 Examples of Crash Scenarios and Vehicle-to-Vehicle Applications......................................26

Figure III-5 Example of V2V Intersection Movement Assist Warning Scenario.......................................27

Figure V-1 In-Vehicle Components of a V2V System...............................................................................68

Figure V-2 Band Plan for DSRC Channel Spectrum..................................................................................93

Figure V-3 Time Division Channel Usage .................................................................................................95

Figure V-4 V2V System ...........................................................................................................................107

Figure V-5 Conventional System..............................................................................................................107

Figure V-6 I-495 & Rt 66 Interchange......................................................................................................109

Figure VII-1 Full comparison of DAC and SP Driver responses .............................................................142

Figure IX-1 Simplified V2V Security System..........................................................................................166

Figure IX-2 Current V2V Security System Design for Deployment and Operations...............................167

Figure IX-3 V2V Security Design Comparison to a Basic PKI................................................................175

Figure IX-4 Security Certificate Management System Organizational Model.........................................190

Figure XI-1 Coverage of RSE by Road Type ...........................................................................................243

Figure XII-1 V2V Benefits Estimation Target Population (Annual) Breakdown ....................................266

Figure XII-2 SIM Logic and Structure .....................................................................................................270

C. Equations

Equation XI-1 Projected Fuel Economy Impact Calculation....................................................................234

Equation XII-1 Benefits Estimation Calculation ......................................................................................260

Equation XII-2 Effectiveness Calculation ................................................................................................261

Equation XII-3 Number of Crashes Avoided Calculation ........................................................................267

Equation XII-4 Application Effectiveness Calculation.............................................................................267
304

Equation XII-5 Exposure Ratio Calculation .............................................................................................268

Equation XII-6 Crash Prevention Ratio Calculation.................................................................................268

Equation XII-7 MAIS Effectiveness Calculation .....................................................................................272

Equation XII-8 MAIS+Injury Probability of Risk....................................................................................274

Equation XII-9 IMA PCP-S Crash Effectiveness Calculation..................................................................277

Equation XII-10 Communication Rate Calculation..................................................................................285
DOT HS 812 014 

August 2014

10690-081514-v2c