1

Errata

Date: February 9, 2021

Issuing Office: Federal Highway Administration

Office of Operations Research and Development

Address: Turner-Fairbank Highway Research Center

6300 Georgetown Pike, McLean, VA 22101

Name of Document: Detailed Concept of Operations: Transportation Systems

Management and Operations/Cooperative Driving Automation 

Use Cases and Scenarios

FHWA Publication No.: FHWA-HRT-20-064

The following changes were made to the document after publication on the Federal Highway 

Administration website:

Location Incorrect Values Corrected Values

Page 3, Table 1 note N/A; new table note added. Note: Table 1 was created by the project team to 

support the development of CDA concepts. During the 

publication process, SAE released a new standard: 

J3216, Taxonomy and Definitions for Terms Related to 

Cooperative Driving Automation for On-Road Motor 

Vehicles (SAE International 2020). Table 1 is similar 

to the defined standards; however, any references to 

the SAE J3216 CDA Cooperation Classes should 

reflect that of the newly approved industry standard.

Page 107, References N/A; new reference added. SAE International. (2020). Taxonomy and Definitions 

for Terms Related to Cooperative Driving Automation 

for On-Road Motor Vehicles, J3216-202005, SAE 

International, Warrendale, PA. Available online: 

https://www.sae.org/standards/content/j3216_202005/, 

last accessed February 9, 2021.

N/A = not applicable.
Research, Development, and Technology

Turner-Fairbank Highway Research Center

6300 Georgetown Pike

McLean, VA 22101-2296

PUBLICATION NO. FHWA-HRT-20-064 DECEMBER 2020 

Detailed Concept of Operations: 

Transportation Systems Management 

and Operations/Cooperative Driving 

Automation Use Cases and Scenarios
FOREWORD

The Federal Highway Administration’s Turner-Fairbank Highway Research Center performs 

advanced research into several areas of transportation technology. The Office of Operations 

Research and Development focuses on improving operations-related technology through 

research, development, and testing. 

This report presents a detailed concept of operations (ConOps) for the four transportation 

systems management and operations (TSMO) use cases—basic travel, traffic-incident 

management, road-weather management, and work-zone management—defined as part of the 

high-level ConOps for the CARMASM effort to define and develop a set of testable use cases that 

demonstrate how cooperative driving automation capabilities can be integrated with TSMO 

strategies. This detailed ConOps lays out the selected example situations under the Group 1 

priority situations. For each priority situation, the operational needs, operational design domain, 

associated stakeholders, concept diagrams, information flows, triggers, and functional 

requirements were identified. This report is intended for all transportation stakeholders interested 

in CARMA and the relationship between cooperative driving automation and transportation 

systems management and operations strategies.

Brian P. Cronin, P.E. 

Director, Office of Safety and Operations 

Research and Development 

Notice

This document is disseminated under the sponsorship of the U.S. Department of Transportation 

(USDOT) in the interest of information exchange. The U.S. Government assumes no liability for 

the use of the information contained in this document. 

The U.S. Government does not endorse products or manufacturers. Trademarks or 

manufacturers’ names appear in this report only because they are considered essential to the 

objective of the document. 

Quality Assurance Statement

The Federal Highway Administration (FHWA) provides high-quality information to serve 

Government, industry, and the public in a manner that promotes public understanding. Standards 

and policies are used to ensure and maximize the quality, objectivity, utility, and integrity of its 

information. FHWA periodically reviews quality issues and adjusts its programs and processes to 

ensure continuous quality improvement.
TECHNICAL REPORT DOCUMENTATION PAGE

1. Report No.

FHWA-HRT-20-064

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

4. Title and Subtitle

Detailed Concept of Operations: Transportation Systems 

Management and Operations/Cooperative Driving Automation 

Use Cases and Scenarios

5. Report Date

December 2020

6. Performing Organization Code

7. Author(s)

Sudhakar Nallamothu (ORCID: 0000-0002-7457-3704), 

John Stark (ORCID: 0000-0002-1558-4630), Elizabeth Birriel

(ORCID: 0000-0002-8945-0715), Imran Inamdar (ORCID: 0000-

0002-8395-2044), Nu Rosenbohm, Aafiya Shah (ORCID: 0000-

0003-0731-0653), Joel Ticatch, Govindarajan Vadakpat

(HRDO-20; ORCID: 0000-0001-9060-3216), and

Taylor Lochrane (HRDO-10; ORCID: 0000-0002-1933-6554) 

8. Performing Organization Report No.

9. Performing Organization Name and Address

Leidos, Inc.

11251 Roger Bacon Drive

Reston, VA 20190

Kapsch TrafficCom North America

8201 Greensboro Drive, Suite 1002

McLean, VA 22102

10. Work Unit No.

11. Contract or Grant No.

DTFH61-16-D00030

12. Sponsoring Agency Name and Address

Federal Highway Administration

Office of Safety and Operations Research and Development

6300 Georgetown Pike

McLean, VA 22101

13. Type of Report and Period Covered

Final Report; August 2018–August 2020

14. Sponsoring Agency Code

HRDO

15. Supplementary Notes

Govindarajan Vadakpat (HRDO-20) and Taylor Lochrane (HRDO-10) were the Contracting Officer’s 

Representatives.

16. Abstract

This report presents the detailed concept of operations (ConOps) in support of the CARMA PlatformSM sponsored 

by the Federal Highway Administration’s Office of Operations Research and Development. The high-level 

ConOps focuses on four transportation systems management and operations use cases—basic travel, 

traffic-incident management, road-weather management, and work-zone management—and explores the 

framework of those relationships in greater detail. As part of the high-level ConOps, researchers identified 

approximately 160 different situations falling under each of the 4 use cases. This detailed ConOps identifies the 

selected priority situations under Group 1 priority use cases. For each priority situation, the research team 

identified the operational needs, operational design domain, associated stakeholders, concept diagrams, 

information flows, triggers, and functional requirements. Each situation includes an applicable scenario 

description and a user requirements traceability matrix. 

17. Key Words

Transportation systems management and operations, 

TSMO, automated driving system, ADS, 

computer-aided dispatch, cooperative driving 

automation, CDA

18. Distribution Statement

No restrictions. This document is available to the public 

through the National Technical Information Service, 

Springfield, VA 22161.

http://www.ntis.gov

19. Security Classif. (of this report)

Unclassified

20. Security Classif. (of this page)

Unclassified

21. No. of Pages

115 

22. Price

N/A

Form DOT F 1700.7 (8-72) Reproduction of completed page authorized.
ii
iii

TABLE OF CONTENTS

CHAPTER 1. INTRODUCTION ................................................................................................ 1

Purpose..................................................................................................................................... 1

Document Overview................................................................................................................ 2

CHAPTER 2. USE CASES AND PRIORITY SITUATIONS .................................................. 5

Typology................................................................................................................................... 5

ADS Vehicle Travel Areas...................................................................................................... 6

Situation Groups ................................................................................................................. 7

Situations............................................................................................................................. 9

Priority Situations by Use Case ........................................................................................... 18

Group 1 Priority Situations ............................................................................................... 20

Group 2 Priority Situations ............................................................................................... 21

CHAPTER 3. BASIC TRAVEL USE CASE ............................................................................ 23

Priority Situation 1 Treatment: ADS-Equipped Vehicle Merging onto a Highway ....... 23

Operational Needs ............................................................................................................. 23

Stakeholders and Entities .................................................................................................. 24

User-Oriented Operational Description ............................................................................ 25

Requirements for Merging onto a Highway ..................................................................... 28

Performance Metrics ......................................................................................................... 29

Requirements Traceability Matrix for Operational Needs and Functional 

Requirements .................................................................................................................... 30

CHAPTER 4. USE CASE: TIM ................................................................................................ 37

Priority Situation 2 Treatment: Vehicle Moves out of the Way of an 

ADS-Equipped Emergency/First-Responder Vehicle ....................................................... 37

Operational Needs ............................................................................................................. 37

Stakeholders and Entities .................................................................................................. 38

User-Oriented Operational Description ............................................................................ 39

Requirements for Vehicles Moving out of the Way of an ADS-Equipped 

Emergency/First-Responder Vehicle ................................................................................ 41

Performance Metrics ......................................................................................................... 44

Requirements Traceability Matrix for TIM Operational Needs and Functional 

Requirements .................................................................................................................... 45

CHAPTER 5. USE CASE: RWM.............................................................................................. 51

Priority Situation 3 Treatment: ADS-Equipped Vehicles Slow Down/Increase Gap 

When Passing Over Wet Pavement ..................................................................................... 51

Operational Needs ............................................................................................................. 52

Stakeholders and Entities .................................................................................................. 53

User-Oriented Operational Description ............................................................................ 53

Trigger to Invoke Situation for ADS-Equipped Vehicles Slowing down and 

Increasing Gap When Passing over Wet Pavement .......................................................... 56

Requirements for ADS-Equipped Vehicles Slowing Down and Increasing Gap 

When Passing Over Wet Pavement .................................................................................. 56

Performance Metrics ......................................................................................................... 59
iv

Requirements Traceability Matrix for Road Weather Management Operational 

Needs and Functional Requirements ................................................................................ 60

CHAPTER 6. USE CASE: WZM .............................................................................................. 69

Priority Situation 4 Treatment: ADS-Equipped Vehicles Navigating a One-Lane, 

Two-Way Traffic Taper in a Work Zone ........................................................................... 69

Operational Needs ............................................................................................................. 69

Stakeholders and Entities .................................................................................................. 70

User-Oriented Operational Description ............................................................................ 71

Requirements .................................................................................................................... 75

Performance Metrics ......................................................................................................... 77

Requirements Traceability Matrix for WZM Operational Needs and Functional 

Requirements .................................................................................................................... 78

APPENDIX. KEY TSMO STRATEGIES AND THEIR RELATIONSHIP TO 

COOPERATIVE ADS ................................................................................................................ 85

ACKNOWLEDGMENTS ........................................................................................................ 105

REFERENCES .......................................................................................................................... 107
v 

LIST OF FIGURES

Figure 1. Illustration. Relationship between travel areas, situation groups, and specific 

situations. ............................................................................................................................... 6

Figure 2. Illustration. Automated Driving Systems vehicle travel areas and sequences. ............... 6

Figure 3. Illustration. Prioritization process for choosing situations. ........................................... 19

Figure 4. Illustration. Several stakeholder groups and individual stakeholders per group 

involved in the prioritization process. ................................................................................. 19

Figure 5. Illustration. Basic travel: merging onto a highway. ...................................................... 20

Figure 6. Illustration. WZM: Vehicles navigating a one-lane, two-way traffic taper in a 

work zone. ........................................................................................................................... 20

Figure 7. Illustration. RWM: Vehicle adjusts speed and prepares for other adjustments at 

beginning of weather-event zone. ....................................................................................... 21

Figure 8. Illustration. TIM: Vehicle moves out of way and clears space for first-responder 

vehicles driving toward incident. ........................................................................................ 21

Figure 9. Illustration. Basic travel situational layout. ................................................................... 23

Figure 10. Illustration. Basic travel—ADS-equipped vehicles receiving a notification. ............. 25

Figure 11. Illustration. Basic travel—vehicle transition area. ...................................................... 26

Figure 12. Illustration. Basic travel—vehicle activity area. ......................................................... 27

Figure 13. Illustration. Basic travel—termination area. ............................................................... 27

Figure 14. Illustration. Traffic-Incident Management situational layout. .................................... 37

Figure 15. Illustration. TIM—ADS-equipped vehicles receiving a notification. ......................... 39

Figure 16. Illustration. TIM—vehicle transition area. .................................................................. 40

Figure 17. Illustration. TIM—vehicle activity area. ..................................................................... 40

Figure 18. Illustration. TIM—termination area. ........................................................................... 41

Figure 19. Illustration. Road Weather Management situational layout. ....................................... 52

Figure 20. Illustration. RWM—ADS-equipped vehicles receiving a notification. ...................... 54

Figure 21. Illustration. RWM—vehicle transition area. ............................................................... 55

Figure 22. Illustration. RWM—vehicle activity area. .................................................................. 55

Figure 23. Illustration. RWM—termination area. ........................................................................ 56

Figure 24. Illustration. WZM situational layout. .......................................................................... 69

Figure 25. Illustration. WZM-ADS-equipped vehicles receiving a notification. ......................... 72

Figure 26. Illustration. WZM—vehicle transition area. ............................................................... 73

Figure 27. Illustration. WZM—vehicle activity area. ................................................................... 74

Figure 28. Illustration. WZM—termination area. ......................................................................... 74
vi 

LIST OF TABLES

Table 1. Relationships between Automation Levels and Cooperation Classes. ............................. 3

Table 2. Operational needs of merging onto a highway. .............................................................. 24

Table 3. Operational needs for ADS-equipped vehicles merging onto a highway. ...................... 24

Table 4. Operational needs for non-ADS-equipped vehicles (human driver) merging onto a 

highway. .............................................................................................................................. 24

Table 5. Operational needs for traffic management service. ........................................................ 24

Table 6. Requirements for merging onto a highway. .................................................................... 28

Table 7. Requirements traceability matrix for merging onto a highway. ..................................... 31

Table 8. Operational needs for TIM. ............................................................................................ 38

Table 9. TIM—operational needs for ADS-equipped vehicles. ................................................... 38

Table 10. TIM—operational need for non-ADS-equipped vehicles (human driver). .................. 38

Table 11. TIM—operational needs for TMS. ............................................................................... 38

Table 12. Requirements for vehicles moving out of the way of an ADS-equipped 

emergency/first-responder vehicle. ..................................................................................... 42

Table 13. Requirements traceability matrix for vehicles moving out of the way of an 

ADS-equipped emergency/first-responder vehicle. ............................................................ 45

Table 14. Operational needs for RWM. ........................................................................................ 52

Table 15. RWM—operational needs for ADS-equipped vehicle systems. .................................. 52

Table 16. RWM—operational needs for non-ADS equipped vehicles (human driver). .............. 52

Table 17. RWM—operational needs for TMS. ............................................................................ 53

Table 18. Requirements and operational needs for ADS-equipped vehicles slowing down 

and increasing gap when passing over wet pavement. ........................................................ 57

Table 19. Requirements traceability matrix for ADS-equipped vehicles slowing down and 

increasing gap when passing over wet pavement. ............................................................... 60

Table 20. Operational needs for WZM. ........................................................................................ 70

Table 21. WZM—operational needs for ADS-equipped vehicles in a work zone. ...................... 70

Table 22. WZM—operational needs for non-ADS equipped vehicles (human driver). ............... 70

Table 23. WZM—operational needs for TMS. ............................................................................. 70

Table 24. Requirements for ADS-equipped vehicles navigating a one-lane, two-way traffic 

taper in a work zone. ........................................................................................................... 75

Table 25. Requirements traceability matrix for ADS-equipped vehicles navigating a 

one-lane, two-way traffic taper in a work zone. .................................................................. 79

Table 26. TSMO strategies for arterial management. ................................................................... 85

Table 27. TSMO strategies for ATM. ........................................................................................... 87

Table 28. TSMO strategies for congestion pricing. ...................................................................... 89

Table 29. TSMO strategies for emergency transportation operations. ......................................... 90

Table 30. TSMO strategies for freight technology and operations. .............................................. 91

Table 31. TSMO strategies for integrated corridor management. ................................................ 92

Table 32. TSMO strategies for managed lanes. ............................................................................ 93

Table 33. TSMO strategies for road weather management. ......................................................... 94

Table 34. TSMO strategies for safety management...................................................................... 96

Table 35. TSMO strategies for special event management. ......................................................... 96

Table 36. TSMO strategies for TIM. ............................................................................................ 97

Table 37. TSMO strategies for traveler information. ................................................................... 98
vii 

Table 38. TSMO strategies for travel demand management. ....................................................... 99

Table 39. TSMO strategies for transit operations and management. ............................................ 99

Table 40. TSMO strategies for WZM. ........................................................................................ 100

Table 41. Other TSMO strategies. .............................................................................................. 100

Table 42. Potential new TSMO strategies and relationship to CDA data. ................................. 101

Table 43. TSMO strategies not expected to be impacted by CDA data. .................................... 103
viii

LIST OF ACRONYMS

ABS antilock braking system 

ADS automated driving system 

AFAD automated flagger assistance device

ATM active traffic management

CDA cooperative driving automation 

ConOps concept of operations 

DOT department of transportation 

FHWA Federal Highway Administration

ITS intelligent transportation systems

MUTCD Manual on Uniform Traffic Control Devices

NAK negative acknowledgment 

OBU onboard unit 

ODD operational design domain 

RSU roadside units 

RWIS road weather information system

RWM road-weather management

SPaT signal phase and timing

TCD traffic-control devices 

TIM traffic-incident management

TMC Traffic Management Center

TMS transportation management service 

TSMO transportation systems management and operations 

TSP transit signal priority

VMS variable message sign

VSL variable speed limit

WZM work-zone management
1 

CHAPTER 1. INTRODUCTION

PURPOSE

This report presents the detailed concept of operations (ConOps) in support of the CARMA 

PlatformSM sponsored by the Federal Highway Administration’s (FHWA’s) Office of Operations 

Research and Development. This ConOps is another step in the ongoing CARMASM effort to 

define and develop a set of testable use cases that demonstrate how cooperative driving 

automation (CDA) capabilities can be integrated with transportation systems management and 

operations (TSMO) strategies.

This report was published with the High-Level Concept of Operations: Examination of the 

Relationships Between Transportation Systems Management and Operations Strategies and 

Cooperative Driving Automation (FHWA-HRT-20-063), which examined the essentials in the 

TSMO/CDA relationship by looking at the range of traditional TSMO strategies for operating 

and managing transportation infrastructure and identifying those strategies expected to be 

impacted by the introduction of CDA technologies (FHWA 2020). The high-level ConOps 

focused on four sets of use cases: basic travel, traffic-incident management (TIM), road-weather 

management (RWM), and work-zone management (WZM). The use cases explored the 

framework of the TSMO/CDA relationship in greater detail and examined the actions that each 

entity responsible for TSMO activities (e.g., an organization operating a transportation 

management service [TMS]) would perform to achieve the TSMO strategy. The high-level 

ConOps mapped whether and how CDA will impact existing TSMO use-case activities. This 

mapping considered both the levels of vehicle automation and classes of vehicle cooperation. 

As part of the high-level ConOps, the research team identified approximately 160 situations 

classified under each of the 4 identified use cases. Domain experts assisted with prioritizing 

these situations. Ultimately, two groups of priorities, with four situations each, were determined 

for initial consideration within CARMA.

This detailed ConOps identifies the selected priority situations under the Group 1 priority use 

cases. For each priority situation, researchers identified operational needs, operational design 

domain, associated stakeholders, concept diagrams, information flows, triggers, and functional 

requirements. Each situation includes an applicable scenario description and a user requirements 

traceability matrix.

The example situations presented in this document are designed to allow for building associated 

algorithms, integrating the algorithms into CARMA, and testing the algorithms under 

proving-ground or onroad conditions within the next steps of CARMA. 
2 

DOCUMENT OVERVIEW

This detailed ConOps includes the following components: 

• Use cases and priority situations. Brief descriptions of the four use cases, the automated 

driving system (ADS) vehicle travel areas used within each use case, the situation groups, 

and the situations. This section also includes a brief description of the process used to 

determine the prioritized situations indicated as follows: 

o Basic travel prioritized situation.

o TIM prioritized situation. 

o RWM prioritized situation. 

o WZM prioritized situation. 

Each of the four prioritized situations includes the following information: operational needs, 

associated stakeholders, concept diagrams, situation triggers, functional requirements, and user

functional requirements traceability matrix.

Short- and long-range communications are defined as follows in the context of this report: 

• Short-range communications: short-distance communications, including the dedicated 

short-range communications suite of protocols, such as Wireless Local Area Network

(WLAN) protocol, IEEE802.11p. 

• Long-range communications: long-distance communications, such as 3G, 4G/LTE, 5G, 

or cellular vehicle-to-everything, which support wide area communication over a cellular 

network. 

This detailed ConOps framework distinguishes between levels of vehicle automation and classes 

of vehicle cooperation. These Cooperation Classes are defined in table 1. 
3

Table 1. Relationships between Automation Levels and Cooperation Classes.

Cooperation 

Class

Automation 

Level 0

Automation 

Level 1

Automation 

Level 2

Automation 

Level 3

Automation 

Level 4

Automation 

Level 5

No 

cooperative 

automation

E.g., 

signage, 

trafficcontrol 

device

Relies on 

onboard sensors 

and driver 

monitoring to 

support limited 

maneuvers.

Relies on 

onboard sensors 

and driver 

monitoring to 

support limited 

maneuvers.

Relies only on 

onboard 

sensors for 

perception to 

support 

maneuvers.

Relies only on 

onboard 

sensors for 

perception to 

support 

maneuvers.

Relies only on 

onboard 

sensors for 

perception to 

support 

maneuvers.

A E.g., brake 

lights, 

traffic signal

Combines 

onboard sensors 

with status data 

and driver 

monitoring to 

support limited 

maneuvers.

Combines 

onboard sensors 

with status data 

and driver 

monitoring to 

support limited 

maneuvers.

Combines 

onboard 

sensors with 

status data for 

improved 

perception to 

support 

maneuvers.

Combines 

onboard 

sensors with 

status data for 

improved 

perception to 

support 

maneuvers.

Combines 

onboard 

sensors with 

status data for 

improved 

perception to 

support 

maneuvers.

B E.g., turn 

signal, 

merge

Supports 

limited 

coordinated 

maneuvers.

Supports 

limited 

coordinated 

maneuvers.

Shares 

intentions to 

support 

coordinated 

maneuvers.

Shares 

intentions to 

support 

coordinated 

maneuvers.

Shares 

intentions to 

support 

coordinated 

maneuvers.

C E.g., hand 

signals, lane 

assignment

Supports 

limited 

cooperative 

maneuvers.

Supports 

limited 

cooperative 

maneuvers.

Enables direct 

negotiations to 

support 

cooperative 

maneuvers.

Enables direct 

negotiations to 

support 

cooperative 

maneuvers.

Enables direct 

negotiations to 

support 

cooperative 

maneuvers.

*Note: Table 1 was created by the project team to support the development of CDA concepts. During the publication

process, SAE released a new standard: J3216, Taxonomy and Definitions for Terms Related to Cooperative Driving 

Automation for On-Road Motor Vehicles (SAE International 2020). Table 1 is similar to the defined standards;

however, any references to the SAE J3216 CDA Cooperation Classes should reflect that of the newly approved 

industry standard.

*Revised 02/09/2021.

5 

CHAPTER 2. USE CASES AND PRIORITY SITUATIONS

TYPOLOGY

The framework concept for TSMO and TMS operations related to the CDA automation defined 

in the high-level ConOps accounts for the different classes of cooperation that can occur between 

equipped vehicles and nonequipped vehicles, roadside equipment, and TMSs. This framework 

design assumes that the data provided by a vehicle arrive at the TMS and data from the TMS are 

provided to a vehicle, regardless of the underlying communications (i.e., short or long range) and 

whether there are intermediate devices (i.e., roadside units) relaying data between the TMS and 

vehicles. The framework also considers the Connected Vehicle Reference Information 

Architecture, particularly the Vehicle Data for Traffic Operations application (USDOT 2016). 

In terms of TSMO-related activities, each use case (or domain) has its own set of operational 

actions. These actions include activities to be performed regardless of the presence of 

ADS-equipped vehicles. Examples of these activities include detection, verification, notification 

and advisories, responses, management of work zones, and management of incidents sites. 

The following sections describe the components and processes used to prioritize situations for 

each use case.

Transportation agencies use TSMO strategies to optimize the safety, mobility, and reliability

performance of existing transportation facilities. High-Level Concept of Operations: 

Examination of the Relationships Between Transportation Systems Management and Operations 

Strategies and Cooperative Driving Automation (FHWA-HRT-20-063) identified 18 TSMO 

strategy groups totaling 90 TSMO strategies.

Each TSMO and cooperation class association defined in the High-Level ConOps (table 3 and 

table 4 of that document) constitutes a unique use case. The use cases highlight the impacts of 

CDA automation levels and cooperation classes on the TSMO strategies. Four use cases—basic 

travel, TIM, RWM, and WZM—were scoped for evaluation and used within the CARMA 

project.

Each use case included the following three layers to focus the evaluation and situation 

determination: (1) vehicle travel areas, (2) situation groups, and (3) example situations. The 

layers are illustrated in figure 1. 
6 

Source: FHWA. 

Figure 1. Illustration. Relationship between travel areas, situation groups, and specific 

situations. 

These layers were created separately for each use case and were subsequently used within the 

situation prioritization process described in the following sections. 

ADS VEHICLE TRAVEL AREAS

Travel areas used in conjunction with ADS-equipped vehicles are areas that ADS-equipped 

general traffic vehicles, first-responder vehicles, and work vehicles typically pass through when 

interacting with nonrecurring roadway issues, such as traffic incidents, road weather events, and 

work zones. Travel areas and their sequences are identified in figure 2. 

Source: FHWA. 

Figure 2. Illustration. Automated Driving Systems vehicle travel areas and sequences. 

In the advanced warning/notification area, the ADS-equipped vehicle is notified by the Traffic 

Management Center (TMC) or another ADS-equipped vehicle in advance of an event along the 

route for situational awareness. Key units of information transmitted from the TMC to the 

vehicle include what hazards may be encountered, such as work zone, incident, or blocked lanes. 

The TMC also notifies the ADS-equipped vehicle where the event is located, which is usually 

the distance to the event. The TMC can also indicate which action the vehicle should take in 

anticipation of the event, such as reducing speed, changing lanes, or taking a detour (Dudek et al. 

2006). The source of the information may include a geofenced broadcast such as a work-zone 

layout or a weather situation from the infrastructure, such as a variable message sign, TMSs, and 

other vehicles capable of sharing information, such as general traffic and first-responder or 

work-zone vehicles.

The transition area is the section of the roadway in which the ADS-equipped vehicle performs 

the actions required to safely maneuver around the event. For example, a work zone that blocks 

the right lane of a four-lane highway will require a vehicle to reduce speed, detect queues, and 

merge into the left lane as it approaches the work-zone area. Traffic-control devices (TCDs) 
7 

(e.g., arrow boards, variable speed limit [VSL] systems, lane control systems, or human flaggers) 

with electronic sensors can guide the vehicles through the transition area. 

The activity area is the work or incident scene in which the first-responder and worker activities 

are performed. The activity area may be on a shoulder, travel lane, or median and can cause 

reductions in roadway capacity and lane availability. An ADS-equipped vehicle needs to 

continuously monitor the activity area for workers, machinery, and safety equipment (e.g., cones 

and barrels) that may inadvertently intrude into the open travel lane. 

The termination area is where the activity area ends and the roadway is back to full capacity, 

allowing vehicles to resume traveling at posted speed limits.

The research team investigated the ADS vehicle travel areas and evaluated them separately for 

each use case. The determination could have led to very different ADS vehicle travel areas but 

were determined to be similar for current use cases. The basic travel use cases, which are 

explained below, were the exception because they did not have distinct ADS vehicle travel areas. 

The resulting ADS vehicle travel areas for the TIM, RWM, and WZM use cases were defined 

according to the ADS vehicle travel areas and sequences shown in figure 2. 

Situation Groups

The ADS-equipped vehicle travel areas are categorized into one or more applicable situation 

groups. The alphabetical part of the situation group represents the use case, and the numeric part 

represents the group number. For example, the first situation group under Basic Travel is A-1. 

The research team defined the following situation groups to link the ADS vehicle travel areas 

with these groups. 

Basic Travel Use Case

• Situation Group A-1: Basic travel operations for all roadway types. 

• Situation Group A-2: Basic travel operations for highways. 

• Situation Group A-3: Basic travel operations for arterials. 

TIM Use Case

• Situation Group B-1: Notifying ADS-equipped vehicle of incident (travel area: advanced 

warning/notification). 

• Situation Group B-2: ADS first-responder vehicles setting up incident site (travel area:

transition area). 

• Situation Group B-3: ADS-equipped vehicles interacting with first-responder vehicles 

approaching incident site (travel area: transition area). 

• Situation Group B-4: ADS-equipped vehicles approaching incident site (travel area:

transition area). 

• Situation Group B-5: ADS-equipped vehicles interacting with traffic-control devices 

(travel area: transition area). 
8 

• Situation Group B-6: ADS-equipped vehicles interacting with first-responder personnel 

warning of incident site (travel area: transition area). 

• Situation Group B-7: ADS-equipped vehicles interacting with people at or in incident site 

(travel area: activity area). 

• Situation Group B-8: ADS-equipped vehicles interacting with incident site on side of 

road (travel area: activity area). 

• Situation Group B-9: ADS-equipped vehicles navigating incident site with lanes blocked 

(travel area: activity area). 

• Situation Group B-10: ADS first-responder vehicles entering, exiting, or inside incident 

site (travel area: activity area). 

• Situation Group B-11: ADS first-responder vehicles clearing incident site (travel area:

termination area). 

RWN Use Case

• Situation Group C-1: Notifying ADS-equipped vehicles of upcoming weather zones 

(travel area: advanced warning/notification). 

• Situation Group C-2: ADS winter-maintenance vehicles detecting weather events (travel 

area: transition area). 

• Situation Group C-3: ADS-equipped vehicles respond to weather events (travel area: 

transition area). 

• Situation Group C-4: ADS-equipped winter-maintenance vehicles responding to weather 

events (travel area: weather area). 

• Situation Group C-5: ADS-equipped vehicles operating within weather event (travel area:

weather area). 

• Situation Group C-6: ADS-equipped winter-maintenance vehicles close out weather 

event (travel area: termination area). 

• Situation Group C-7: ADS-equipped vehicles react to end of weather event (travel area:

termination area). 

WZM Use Case

• Situation Group D-1: Notifying ADS-equipped vehicles of upcoming work zones (travel 

area: advanced warning/notification). 

• Situation Group D-2: Communicating with ADS-equipped vehicles setting up work zones 

(travel area: transition area). 

• Situation Group D-3: ADS-equipped vehicles interacting with traffic-control devices 

(travel area: transition area). 

• Situation Group D-4: ADS-equipped vehicles interacting with work-zone workers and 

flaggers (travel area: transition area). 

• Situation Group D-5: ADS-equipped vehicles interacting with people in and around work 

zones (travel area: activity area). 

• Situation Group D-6: ADS-equipped vehicles interacting with work zones on side of road 

(travel area: activity area). 

• Situation Group D-7: ADS-equipped vehicles navigating work zones with lanes blocked 

(travel area: activity area). 
9 

• Situation Group D-8: ADS-equipped vehicles navigating work zones in different 

configurations (travel area: activity area). 

• Situation Group D-9: ADS-equipped work vehicles entering, exiting, or inside work 

zones (travel area: activity area). 

• Situation Group D-10: ADS-equipped work vehicles taking down a work zone (transition 

area: termination area). 

Situations

Examples of various situations are identified under each situation group based on the use case 

workshop discussions, stakeholder inputs, and adaptations from the Manual on Uniform Traffic 

Control Devices (MUTCD) (FHWA 2009). The situations are not exhaustive, and the situational 

framework is expected to continue growing as work continues. Each situation is coded by a 

decimal place. For instance, the example situations under Situation Group 2 in the RWM use 

case are sequenced A-2.1, A-2.2. 

Specifically, the following situation groups were defined to allow stakeholders to prioritize the 

situations to be investigated as part of the CARMA Platform. 

Basic Travel Use Case

Situation Group A-1: Basic Travel Operations for All Roadway Types. Nonspecialized 

vehicle situations applicable to all roadway types include the following: 

• A-1.1: Managing vehicle platooning (e.g., joining, formation, operation, and dissolution). 

• A-1.2: Managing vehicle strings (cooperative adaptive cruise control). 

• A-1.3: Using cooperative lane changes (when not platooning). 

• A-1.4: Supporting hazard detection. 

• A-1.5: Identifying vehicle by capabilities (e.g., automation level and cooperation class). 

• A-1.6: Screening for overheight/overweight vehicles. 

• A-1.7: Parking a vehicle (including onstreet parking). 

• A-1.8: Navigating railroad crossings. 

• A-1.9: Navigating around school zones. 

• A-1.10: Navigating managed-lane facilities (e.g., high-occupancy toll [HOT] lanes). 

• A-1.11: Interacting with TCDs (e.g., arrow board devices in the middle lane).

Situation Group A-2: Basic Travel Operations for Highways. Nonspecialized vehicle 

situations applicable to roadways with intersections that are not at-grade to other roadways, 

which include interstates and most freeways and expressways, include the following: 

• A-2.1: Merging on/diverging off highway (when not platooning). 

• A-2.2: Merging on/diverging off highway with platoon. 

• A-2.3: Managing active traffic (e.g., speed harmonization). 

• A-2.4: Metering ramp with/without traffic signal prompt. 
10 

Situation Group A-3: Basic Travel Operations for Arterials. Nonspecialized vehicle 

situations applicable to nonhighway roadways, which include local streets, collectors, and 

principal and minor arterials, include the following: 

• A-3.1: Navigating signalized intersections (operating in fixed time, traffic responsive, 

and adaptive). 

• A-3.2: Navigating signalized intersections with priority (priority-eligible vehicles). 

• A-3.3: Navigating nonsignalized intersections (e.g., all-way stop, median crossing). 

• A-3.4: Navigating roundabout (e.g., single lane and multilane). 

• A-3.5: Interacting with pedestrians (e.g., pedestrians crossing roadway perpendicularly or 

crossing side street at intersection with vehicle turning). 

• A-3.6: Interacting with bicycles (e.g., bicycles crossing roadway perpendicularly or 

crossing side street at intersection with turning vehicle). 

TIM Use Case

ADS Vehicle Travel Area: Advanced Warning/Notification Area 

Situation Group B-1: Notifying ADS-equipped vehicle of incident. ADS-equipped vehicles 

must be able to receive notifications in real time and for specific incident scenes in their paths. 

These notifications will be used to plan and, when appropriate, alter travel routes. The following 

situations are examples of vehicle notifications and warnings prior to arrival at an incident site:

• B-1.1: Road closure with diversion. 

• B-1.2: Detour for one travel direction. 

• B-1.3: Detour for closed street. 

• B-1.4: Overlapping routes with detour. 

• B-1.5: Temporary road closure. 

• B-1.6: Notification of end of queue. 

• B-1.7: Estimated incident duration. 

• B-1.8: Incident information for ADS first responders, including incident type, incident 

location, incident severity, and updates on optimal travel route. 

ADS Vehicle Travel Area: Transition Area 

Situation Group B-2: ADS first-responder vehicles setting up incident site. First-responder 

vehicles equipped with ADS must be able to set up the perimeter of an incident site. The 

following situations are examples of incident-site setups: 

• B-2.1: Vehicle setting up first-responder vehicle locations at incident site. 

• B-2.2: Vehicle setting up cones to divert traffic around incident site. 

• B-2.3: First-responder vehicles broadcasting positions to other ADS-equipped vehicles 

and the TMS at incident site. 

Situation Group B-3: ADS-equipped vehicles interacting with first-responder vehicles 

approaching incident site. ADS-equipped vehicles must be able to cooperate with 
11 

first-responder vehicles approaching an incident site. The following situations are examples of 

such cooperation: 

• B-3.1: Vehicle moves out of the way and clears space for first-responder vehicles driving 

toward an incident (i.e., traffic interaction with emergency vehicles). 

• B-3.2: First-responder vehicles setting up cones to divert traffic around incident site. 

• B-3.3: First-responder vehicles broadcasting positions on way to incident site. 

• B-3.4: Establishing geofence around incident scene. 

• B-3.5: Identifying back-of-queue (queue management). 

Situation Group B-4: ADS-equipped vehicles approaching incident site. ADS-equipped 

vehicles must be able to address a range of situations when approaching an incident site, 

including the following: 

• B-4.1: Secondary incidents between vehicles approaching incident site. 

• B-4.2: Incidents involving first-responder vehicles. 

Situation Group B-5: ADS-equipped vehicles interacting with traffic-control devices. 

ADS-equipped vehicles must be able to recognize TCDs and the message/information the device 

is conveying. For example, an ADS-equipped vehicle should not confuse a cone or barrier as an 

obstruction and come to a halt, but instead recognize and understand the need to merge into 

another lane. The following items are examples of TCDs used in work zones: 

• B-5.1: Police vehicles with flashing lights warning of an immediate downstream incident 

site. 

• B-5.2: Cones separating an incident site from available roadway lanes. 

Situation Group B-6: ADS-equipped vehicles interacting with first-responder personnel 

warning of incident site. ADS-equipped vehicles must be able to recognize first-responders 

positioned in advance of an incident site. For example, an ADS-equipped vehicle must recognize 

humans warning of an incident site, avoid collisions with humans, and convey the detection of 

humans to other vehicles (e.g., cooperative and collaborative behavior). The following situation 

is an example of interaction with humans in work zones: 

• B-6.1: Hand-signaling by police officers or other authorized personnel. 

ADS Vehicle Travel Area: Activity Area

Situation Group B-7: ADS-equipped vehicles interacting with people at or in incident site. 

ADS-equipped vehicles must be able to recognize people moving at the periphery and crossing 

open lanes within an incident site. For example, an ADS-equipped vehicle must recognize 

humans crossing and working or walking alongside a lane within an incident site and come to a 

stop to avoid collisions, while at the same time conveying the detection of humans to other 

vehicles (cooperative and collaborative behavior). The following situations are examples of 

interactions between the ADS-equipped vehicle and humans:
12 

• B-7.1: Person crossing roadway within an incident site. 

• B-7.2: Person working or walking along a lane within an incident site. 

• B-7.3: First responder stepping out of vehicle.

Situation Group B-8: ADS-equipped vehicles interacting with incident site on side of road. 

ADS-equipped vehicles must be able to recognize an incident site on the side of the road (i.e., on 

the shoulder) that does not close travel lanes. The following situations are examples of 

interactions between the ADS-equipped vehicle and an incident site on the side of the road: 

• B-8.1: Incident on shoulder (e.g., a disabled vehicle or traffic stop). 

• B-8.2: Shoulder incident with minor encroachment of roadway. 

• B-8.3: Incident on onramp or exit ramp. 

• B-8.4: First responder stepping out of vehicle. 

• B-8.5: First-responder vehicles broadcasting their positions at site. 

• B-8.6: Move-Over law. 

Situation Group B-9: ADS-equipped vehicles navigating incident site with lanes blocked. 

ADS-equipped vehicles must be able to recognize lane drops prior to an incident site. Lane drops 

can include multiple lane drops when drops are staggered, but at least one through lane remains 

open. This grouping covers incident sites on either side of the roadway and stranded vehicles in 

the middle lanes. The following situations are examples of ADS-equipped vehicles navigating an 

incident site with blocked lanes: 

• B-9.1: One-lane, two-way traffic taper. 

• B-9.2: Lane closure on two-lane road. 

• B-9.3: Lane closure at intersection (e.g., right- or left-hand, near- or far-side, 

multiple-lane, half road, center, or side). 

• B-9.4: Half-road closure on the far side of intersection. 

• B-9.5: Multiple lane closures at intersection. 

• B-9.6: Closure in center of intersection. 

• B-9.7: Interior lane closure on multilane street. 

• B-9.8: Half-road closure on multilane, high-speed highway. 

• B-9.9: Lane closure on divided highway. 

• B-9.10: Lane closure with temporary traffic barrier. 

• B-9.11: Double-lane closure on freeway. 

• B-9.12: Interior-lane closure on freeway. 

• B-9.13: Incident in vicinity of grade crossing. 

• B-9.14: Lane shift on freeway. 

• B-9.15: Incident in vicinity of the exit ramp. 

• B-9.16: Incident in vicinity of the entrance ramp. 

• B-9.17: Middle lanes on freeway closed and through traffic passes on both sides. 

• B-9.18: Middle lanes on arterial closed and through traffic passes on both sides in same 

or opposite directions. 

• B-9.19: Median crossover on freeway. 

• B-9.20: Median crossover for entrance ramp. 
13 

• B-9.21: Median crossover for exit ramp. 

• B-9.22: Temporary reversible lane using movable barriers. 

Situation Group B-10: ADS first-responder vehicles entering, exiting, or inside incident 

site. First-responder vehicles equipped with ADS must be able to enter and exit an incident site 

regardless of whether the entry or exit points are midblock of the site or at the end of the site. 

The following situations are examples of ADS-equipped first-responder vehicles entering and 

exiting an incident site:

• B-10.1: Entering incident site at midpoint. 

• B-10.2: Exiting incident site at midpoint. 

• B-10.3: Entering incident site by reversing into the back end of incident site. 

• B-10.4: Exiting incident site by reversing out of the back end of incident site. 

• B-10.5: Detecting and interacting with first responders at incident site. 

ADS Vehicle Travel Area: Termination Area 

Situation Group B-11: ADS first-responder vehicles clearing incident site. First-responder 

vehicles equipped with ADS must be able to assist with cleaning an incident site and clearing the 

roadway for recovery. The following situations are examples of first-responders cleaning and 

clearing an incident site: 

• B-11.1: Vehicle performing key actions, such as towing vehicles and cleaning roadway of 

spilled materials. 

• B-11.2: Vehicle removing cones demarcating incident site. 

• B-11.3: Vehicle sending notifications announcing incident clearance. 

RWM Use Case

ADS Vehicle Travel Area: Advanced Warning/Notification of Road Weather 

Situation Group C-1: Notifying ADS-equipped vehicles of upcoming weather zones. 

ADS-equipped vehicles must be able to receive notifications of approaching weather hours in 

advance or on an as-needed basis as conditions warrant. These advanced and as-needed 

notifications will be used to plan for and respond to weather conditions, and potentially to alter 

travel routes. The following situations are examples of notifications and warnings in advance of 

weather areas:

• C-1.1: Detect road weather and pavement conditions. 

• C-1.2: Detect extreme weather events (e.g., low to zero visibility, treacherous/impassable 

roads, abandoned cars).

• C-1.3: Detect road weather events (e.g., major storms, floods, high winds). 

• C-1.4: Geofence to indicate areas not plowed during and after the snow event. 

• C-1.5: Geofence to show roadway/lanes blocked due to weather. 

• C-1.6: Employ weather-responsive traffic signals/ramp metering. 
14 

• C-1.7: Employ weather-responsive variable message sign (VMS) messaging

(Dudek et al. 2006). 

• C-1.8: Employ signal preemption for maintenance vehicles. 

• C-1.9: Automated snowplowing. 

• C-1.10: Automated snowplowing (specialized; e.g., bridges and work zones). 

• C-1.11: Platooning under adverse-weather conditions. 

• C-1.12: Road closure due to weather conditions with diversion. 

• C-1.13: Road closure due to weather conditions with off-area detour. 

• C-1.14: Employee weather-responsive control strategies (e.g., VSL, chain, and/or tire 

requirements). 

ADS Vehicle Travel Area: Transition Area 

Situation Group C-2: ADS winter-maintenance vehicles detecting weather events. 

Winter-maintenance vehicles equipped with ADS must be able to detect and report the beginning 

of the weather-event area. The following situations are examples of the detection and reporting: 

• C-2.1: Vehicle detects weather-event area. 

• C-2.2: Vehicle reports on weather-event area. 

Situation Group C-3: ADS-equipped vehicles respond to weather events. ADS-equipped 

vehicles must be able to adjust their travel at the beginning of the weather-event area. The

following situations are examples of adjusting travel at the beginning of a weather event: 

• C-3.1: Vehicle adjusts speeds and prepares for other adjustments at the beginning of the 

weather-event area. 

• C-3.2: Vehicle informs vehicle operator and pulls over so operator can place chains on 

vehicle’s tires prior to arriving at the weather-event area. 

ADS Vehicle Travel Area: Weather Area

Situation Group C-4: ADS winter-maintenance vehicles responding to weather events. 

Winter-maintenance vehicles equipped with ADS must be able to work and respond to weather 

events. The following situations are examples of ADS-equipped vehicles working and 

responding to weather events: 

• C-4.1: Vehicle conveys it is working the weather event (e.g., using hazard lights). 

• C-4.2: Vehicle dispenses treatment onto roadways according to the current 

weather-response plan. 

• C-4.3: Snowplow operates independently as a unit. 

• C-4.4: Snowplows operate collaboratively as coordinated units. 

Situation Group C-5: ADS-equipped vehicles operating within weather event. 

ADS-equipped vehicles, having adjusted their travel at the beginning of the weather-event zone, 

move through the weather-event area or seek shelter. The following situations are examples of 

ADS-equipped vehicles driving through or seeking shelter from the weather event: 
15 

• C-5.1: Vehicle carefully drives through weather-event area. 

• C-5.2: Vehicle seeks shelter, which might include parking the vehicle to wait for the

weather event to end. 

ADS Vehicle Travel Area: Termination Area 

Situation Group C-6: ADS winter-maintenance vehicles close out weather event.

Winter-maintenance vehicles equipped with ADS return to normal and/or clean-up operations 

after a weather event ends. The following situations are examples of ending the response plan 

and cleanup activities:

• C-6.1: Vehicle ends weather-event response plan. 

• C-6.2: Vehicle performs cleanup operations according to the weather-event management 

plan and need. 

• C-6.3: Vehicle returns to home base. 

Situation Group C-7: ADS-equipped vehicles react to end of weather event. ADS-equipped 

vehicles return to normal operations at the end of a weather event. The following situations are 

examples of such activities:

• C-7.1: Vehicle adjusts speed to normal operations at the end of the weather event. 

• C-7.2: Vehicle operator pulls the vehicle over to the side of the road to remove chains on 

vehicle at the end of the weather event. 

WZM Use Case

ADS Vehicle Travel Area: Advanced Warning/Notification of Work-Zone Area

Situation Group D-1: Notifying ADS-equipped vehicles of upcoming work zones.

ADS-equipped vehicles must be able to receive notifications before entering a work zone. This 

advanced notification is used to plan and potentially alter travel routes used by the 

ADS-equipped vehicle. An ADS-equipped vehicle must also be able to receive notifications of 

work zones that were set up on an as needed basis (i.e., utility work), which includes temporary 

or mobile work zones. The following situations are examples of notification warnings in advance 

of work zones: 

• D-1.1: Road closure with diversion. 

• D-1.2: Road closure with offsite detour. 

• D-1.3: Detour for one travel direction. 

• D-1.4: Detour for closed street. 

• D-1.5: Overlapping routes with detour. 

• D-1.6: Temporary road closure. 

• D-1.7: Work zone on shoulder. 

• D-1.8: Work zone closure of lanes. 

• D-1.9: Work zone with flagger or traffic-control devices. 
16 

ADS Vehicle Travel Area: Transition Area 

Situation Group D-2: Communicating with ADS-equipped vehicles setting up work zones. 

ADS-equipped work vehicles must be able to follow instructions to set up the work zone 

according to the traffic-management plan, which includes temporary or mobile work zones. The 

following situations are examples of communicating with ADS-equipped vehicles that set up 

work zones: 

• D-2.1: Work vehicle setting up cones or barrels to delineate the work zone. 

• D-2.2: Work vehicle setting up barriers to delineate the work zone. 

Situation Group D-3: ADS-equipped vehicles interacting with traffic-control devices. 

ADS-equipped vehicles must be able to recognize traffic-control devices. For example, an 

ADS-equipped vehicle must not confuse a cone or barrier as an obstruction and therefore come 

to a halt; instead, the vehicle must recognize and understand the need to merge into another lane. 

This includes temporary or mobile work zones. The following situations are examples 

ADS-equipped vehicles interacting with traffic-control devices:

• D-3.1: Stop/Slow automated flagger assistance device (AFAD). 

• D-3.2: Red/yellow-lens AFAD. 

• D-3.3: Police vehicles with flashing lights warning of immediate downstream work zone. 

• D-3.4: Cones or barriers separating work zone from roadway lanes. 

Situation Group D-4: ADS Vehicles Interacting with work-zone workers and flaggers. 

ADS-equipped vehicles must be able to recognize workers positioned in advance of a work zone. 

For example, an ADS-equipped vehicle must recognize human flaggers and avoid collision with 

the flaggers. The ADS-equipped vehicle must also be able to convey the detection of humans to 

other vehicles (cooperative and collaborative behavior). This includes temporary or mobile work 

zones. The following items are examples of humans in work zones: 

• D-4.1: Hand-signaling devices by flaggers. 

• D-4.2: Hand-signaling by police officers or other authorized staff. 

ADS Vehicle Travel Area: Activity Area

Situation Group D-5: ADS-equipped vehicles interacting with people in and around work 

zones. ADS-equipped vehicles must be able to recognize people moving at the periphery and 

crossing open lanes within a work zone. For example, an ADS-equipped vehicle must recognize 

humans crossing and working or walking alongside a lane within a work zone and come to a stop 

to avoid collisions while at the same time convey the detection of humans to other vehicles 

(cooperative and collaborative behavior). This includes temporary and mobile work zones. The 

following situations are examples of ADS-equipped vehicles recognizing humans in a work 

zone:

• D-5.1: Person crossing roadway within a work-zone area. 

• D-5.2: Person working or walking along a lane within a work-zone area. 
17 

Situation Group D-6: ADS-equipped vehicles interacting with roadside work zones.

ADS-equipped vehicles must be able to recognize work zones (and their associated 

traffic-control devices) that are operating on the side of the road (e.g., the shoulder) but do not 

close any through lanes. This includes temporary or mobile work zones. The following situations 

are examples of interactions with roadside-based work zones: 

• D-6.1: Shoulder work. 

• D-6.2: Short-duration work zone on a shoulder. 

• D-6.3: Shoulder closure on freeway. 

• D-6.4: Shoulder work with minor encroachment of roadway. 

• D-6.5: Partial exit-ramp closure. 

Situation Group D-7: ADS-equipped vehicles navigating work zones with lanes blocked. 

ADS-equipped vehicles must be able to recognize lane drops prior to the work zone. Lane drops 

can include multiple lane drops when drops are staggered, but at least one through lane remains 

open. This includes temporary or mobile work zones. The following situations are examples of 

interactions navigating work zones with blocked lanes: 

• D-7.1: One-lane, two-way traffic taper. 

• D-7.2: Lane closure on two-lane road using flaggers. 

• D-7.3: Lane closure on two-lane road using traffic-control signals. 

• D-7.4: Lane closure on a right- or left-hand, near- or far-side, multiple-lane, half-road, 

center, or side intersection. 

• D-7.5: Interior lane closure on multilane street. 

• D-7.6: Half-road closure on multilane, high-speed highway. 

• D-7.7: Stationary lane closure on divided highway. 

• D-7.8: Lane closure with temporary traffic barrier. 

• D-7.9: Double-lane closure on freeway. 

• D-7.10: Interior-lane closure on freeway. 

• D-7.11: Work in vicinity of grade crossing. 

• D-7.12: Lane shift on freeway. 

• D-7.13: Work in vicinity of exit ramp. 

Situation Group D-8: ADS-equipped vehicles navigating work zones in different 

configurations. ADS-equipped vehicles must be able to recognize lane drops prior to a work 

zone when the middle lanes are closed and at least one through lane on each side stays open 

(or where ADS-equipped vehicles need to cross over into opposite lanes). This includes 

temporary or mobile work zones. The following situations are examples of interactions of 

ADS-equipped vehicles navigating work zones in different configurations: 

• D-8.1: Middle lanes on freeway closed and through traffic passes on both sides. 

• D-8.2: Middle lanes on arterial closed and through traffic on both sides passes in same or 

opposite directions. 

• D-8.3: Median crossover on freeway. 

• D-8.4: Median crossover for entrance ramp. 

• D-8.5: Median crossover for exit ramp. 
18 

• D-8.6: Work in vicinity of entrance ramp. 

• D-8.7: Temporary reversible lane using movable barriers. 

• D-8.8: Counterflow and reverse lanes for work zones. 

Situation Group D-9: ADS-equipped work vehicles entering, exiting, or inside work zones. 

ADS-equipped work vehicles must be able to enter and exit a work zone regardless of whether 

the entry and exit points are in the middle of the work zone or at the end of the work zone. This 

includes temporary or mobile work zones. The following situations are examples of such 

interactions in work zones: 

• D-9.1: Entering and exiting in the middle of the work zone. 

• D-9.2: Entering and exiting the work zone by backing into the back end of the work zone. 

• D-9.3: Detecting and interacting with workers in the work zone. 

ADS Vehicle Travel Area: Termination Area 

Situation Group D-10: ADS-equipped work vehicles dismantling a work zone. 

ADS-equipped vehicles must be able to follow instructions to dismantle a work zone according 

to the traffic-management plan. This includes temporary or mobile work zones. The following 

items are examples of such interactions in work zones:

• D-10.1: Vehicle removing barriers delineating a work zone. 

• D-10.2: Vehicle removing a cone. 

PRIORITY SITUATIONS BY USE CASE

The research team created a prioritization process to choose the most pressing situations for 

which CARMA team members will develop and field test algorithms to use in ADS-equipped 

vehicles. The process included the steps shown in figure 3 and involved extensive stakeholder 

outreach. At the beginning of this project, researchers convened a workshop that included major 

stakeholders; these stakeholders formed the governing committee. Following the workshop, 

researchers conducted individual workshops with stakeholders from each of the four use cases.

Once the individual workshops were completed, stakeholders participated in a ranking and 

prioritization exercise for the various priority situations within each use case. The governing 

committee held a final stakeholder workshop to inform and receive comments on the situations 

deemed a priority.
19 

Source: FHWA. 

Figure 3. Illustration. Prioritization process for choosing situations. 

Of the 160 previously identified situations in the preceding sections, stakeholders prioritized 1 or 

more situations across each of the 4 use cases. Stakeholders across research and academia, State 

and local agencies, consultants, and other companies were identified, contacted, and invited to 

participate in the prioritization process. Figure 4 lists some of the stakeholders involved. 

Source: FHWA. 

Figure 4. Illustration. Several stakeholder groups and individual stakeholders per group 

involved in the prioritization process. 
20 

Based on stakeholder input, as well as CARMA needs, the highest priority items were 

determined to be, in descending order, as follows. Figure 5 through figure 8 illustrate the priority 

situations to be evaluated. All vehicles that have a symbol next to them are equipped with 

automated driving systems. 

Group 1 Priority Situations 

Basic Travel: Merging onto a highway

Source: FHWA.

Figure 5. Illustration. Basic travel: merging onto a highway. 

WZM: Vehicles navigating a one-lane, two-way traffic taper in a work zone 

Source: FHWA.

Figure 6. Illustration. WZM: Vehicles navigating a one-lane, two-way traffic taper in a 

work zone.
21 

RWM: Vehicle adjusts speed and prepares for other adjustments at beginning of 

weather-event zone

Source: FHWA.

Figure 7. Illustration. RWM: Vehicle adjusts speed and prepares for other adjustments at 

beginning of weather-event zone.

TIM: Vehicle moves out of the way and clears space first-responder vehicles driving toward 

the incident

Source: FHWA.

Figure 8. Illustration. TIM: Vehicle moves out of way and clears space for first-responder 

vehicles driving toward incident.

Group 2 Priority Situations 

CARMA team members will first develop algorithms for the Group 1 priority situations. Team 

members will develop algorithms for Group 2, detailed in the following list, as a future step. This 

report focuses on the Group 1 priority situations. 

• WZM: Road closure with diversion. 

• TIM: Move-Over law. When approaching a stationary emergency vehicle with flashing 

lights, the approaching traffic moves out of the lane adjacent to the emergency vehicle.

• Basic Travel: Navigate signalized intersection.

• TIM: Lane shift on freeway.

23 

CHAPTER 3. BASIC TRAVEL USE CASE

PRIORITY SITUATION 1 TREATMENT: ADS-EQUIPPED VEHICLE MERGING

ONTO A HIGHWAY

The subject of this situational analysis of priority situation 1 is an ADS feature with an 

operational design domain (ODD) that includes ADS-equipped vehicles merging from an 

onramp onto an acceleration lane on a highway populated by vehicles of different automation 

levels and cooperation classes.

Priority situation 1 includes ADS vehicle travel areas with various interactions between vehicles 

equipped and not equipped with ADS. For this situation, the ADS-equipped vehicle travel areas 

of advanced warning/notification, transition, activity, and termination were used. 

Priority situation 1 involves a vehicle driving on the onramp approaching the merge area of the 

highway. Two vehicles are in the right lane of the highway. All vehicles approach the onramp 

acceleration lane at the same time, and the vehicle on the ramp attempts to merge onto the 

highway between the two vehicles traveling in the right lane. This situation considers several 

vehicle configurations, including different levels of automation and classes of cooperation 

capabilities among the vehicles.

Figure 9 shows the situational layout of priority situation 1. To investigate this situation, test 

vehicles with different classes of cooperation capabilities were used. The other vehicles shown in 

figure 9 are not essential when executing tests in this situation. 

Source: FHWA.

Figure 9. Illustration. Basic travel situational layout. 

Operational Needs

Priority situation 1 is intended to address specific operational user needs defined in table 2

through table 5. 
24 

Table 2. Operational needs of merging onto a highway. 

Operational 

Need 

Identifier Operational Needs 

BT-N1.01 Improve safety and efficiency of highway merge maneuvers.

BT-N1.02 Maintain situational awareness during merging operations.

BT-N1.03 Gather, integrate, process, and disseminate data.

Table 3. Operational needs for ADS-equipped vehicles merging onto a highway. 

Operational 

Need 

Identifier Operational Needs for ADS-Equipped Vehicles 

BT-N1.04 Need location and speed information from vehicles near the ADS-equipped vehicle.

BT-N1.05 Need merging vehicle speeds, locations, and braking information from neighboring vehicles.

BT-N1.06 Need main line vehicle speeds, locations, and braking information from neighboring vehicles.

BT-N1.07 Need to detect vehicles incapable of cooperating with other vehicles.

Table 4. Operational needs for non-ADS-equipped vehicles (human driver) merging onto a 

highway. 

Operational 

Need 

Identifier Operational Needs for Non-ADS-Equipped Vehicles (Human Driver)

BT-N1.08 Need advance information regarding approaching ramps.

BT-N1.09 Need visual alerts from vehicles in the vicinity showing intent to merge onto the highway.

BT-N1.10 Need visual alerts from vehicles in the vicinity showing intent to allow vehicle merge from onramp 

onto the highway.

Table 5. Operational needs for traffic management service.

Operational 

Need 

Identifier Operational Needs for Traffic Management Service

BT-N1.11 Need to gather and process data from intelligent transportation systems (ITS) devices and 

ADS-equipped vehicles to monitor current traffic conditions.

Stakeholders and Entities

Researchers can execute the operational situation using several vehicles. CARMA’s focus is on 

Automation Level 3 or higher and Cooperation Class B capabilities or higher; although under 

real-world conditions, other vehicles will also be encountered that will be equipped with lower 

automation levels and cooperation classes. The following entities, and their associated minimum 

vehicle configurations, should be considered when executing this operational situation with 

CARMA:

• Vehicle onramp: ADS-equipped vehicle with Automation Level 3 and Cooperation 

Class B. 

• Vehicle 1 (rear) on mainline lane: ADS-equipped vehicle with Automation Level 3 and 

Cooperation Class B. 

• Vehicle 2 (front) on mainline lane: ADS-equipped vehicle with Automation Level 3 and 

Cooperation Class B. 
25 

Vehicle 1 is the second vehicle on the mainline lanes, and vehicle 2 is the leading vehicle.

Another stakeholder is the TMS operator (or software package) that will monitor the positions of 

each vehicle for recording and storage purposes. This situation does not include any field device 

equipment that needs to be managed; therefore, the TMS operator is passive in this situation. If 

an RSU is used for the communications, then the TMS will need to monitor the communications 

associated with the RSU.

User-Oriented Operational Description

Concept Diagram 

This priority situation 1 includes four ADS-equipped vehicle travel areas—advanced 

warning/notification, transition, activity, and termination—that are explained in detail and are 

suitable for this situation. The priority situation concepts include an overview diagram for each 

travel area for ADS vehicles and a description that shows how vehicles react and respond within 

each travel area of the “Merge onto Highway” situation.

For the following descriptions of ADS vehicle travel areas used within CARMA, researchers

assumed that the involved vehicles support at least Cooperation Class B capabilities. 

Advanced Warning/Notification Vehicle Travel Area

Within the advanced warning/notification vehicle travel area, the ADS-equipped vehicle on the 

ramp broadcasts a notification that it is on the onramp, but not yet on the onramp acceleration 

lane segment. The information in the notification includes location, speed, and heading. 

Each ADS-equipped vehicle on the mainline lanes determines, based on its own location, its speed 

and heading, and whether it anticipates being impacted by the vehicle on the onramp. For example, 

in figure 10, the vehicles shown without the circles are assumed not to be affected by the vehicle 

on the on ramp, while vehicle 1 in the front right-most mainline lane and vehicle 2 in the rear 

right-most mainline lane expect to be affected. 

Source: FHWA.

Figure 10. Illustration. Basic travel—ADS-equipped vehicles receiving a notification.
26 

Vehicle Travel Transition Area

Within the transition area, the ADS-equipped vehicle on the ramp broadcasts a notification that it 

is in the onramp’s acceleration lane, as shown in figure 11. This information includes location, 

speed, and heading, as well as the turn signal, which was turned on by either the vehicle or 

driver.

Each ADS-equipped vehicle on the mainline lanes receiving a notification determines, based on 

its own location, its speed and heading, and whether it needs to maintain its current speed, 

location, and intended path, or whether it should speed up or slow down to accommodate the 

merging vehicle on the onramp. Vehicles capable of Cooperation Class C exchange data to 

negotiate how the merging maneuver will be executed. Data exchanges might include 

interactions between the merging ramp vehicle 1 and the rear mainline lane vehicle 2, during 

which the vehicle on the ramp speeds up slightly and the vehicle in the rear mainline lane slows 

down slightly. This is an example of a merge situation at an onramp. Other situations, such as 

merging in front of mainline vehicles by speeding up or merging behind two mainline vehicles 

by slowing down, are also possible.

Source: FHWA.

Figure 11. Illustration. Basic travel—vehicle transition area. 

Vehicle Travel Activity Area

Within the activity area, the ADS-equipped vehicle on the ramp broadcasts a notification that it 

is about to move from the onramp’s acceleration lane to the mainline lane, shown in figure 12. 

This information includes location, speed, heading, and brake status (for the rear mainline-lane 

vehicle), as well as path prediction. 

Each ADS-equipped vehicle on the mainline lanes receiving notifications determines, based on 

its own location, its speed and heading, and whether it needs to maintain its current speed, 

location, and intended path, or whether it should speed up or slow down slightly to accommodate 

the merging vehicle on the onramp. The predicted path information from the vehicle on the ramp 

is used in these determinations. Vehicles capable of Cooperation Class C exchange data to 

negotiate how the merging maneuver will be executed. This might include data exchanges 

between vehicle 1 on the ramp and vehicle 2 in the mainline lane. Vehicle 1 on the ramp might 
27 

speed up slightly and vehicle 2 on the mainline-lane might slow down slightly to accommodate 

the merge. 

Source: FHWA.

Figure 12. Illustration. Basic travel—vehicle activity area. 

Vehicle Travel Termination Area

Within the termination area, the ADS-equipped vehicle that entered the mainline lanes from the 

ramp finalizes its operational maneuver and broadcasts the completion of its merging activities, 

as shown in figure 13. 

Upon receipt of this information, the ADS-equipped vehicles in the mainline lane return to 

normal driving operation. This may require vehicle 2 in the rear to speed up to reduce the 

headway between itself and the merged vehicle 1. 

Source: FHWA.

Figure 13. Illustration. Basic travel—termination area. 

Trigger to Invoke Situation for Merging onto a Highway 

This merging onto the highway situation is triggered by the vehicle on the ramp indicating that it 

intends to merge onto the highway. The following indicators are designated as triggers to invoke 

responses of mainline vehicles: 
28 

• Broadcast by vehicle equipped with ADS on the ramp. 

• Acceleration of any vehicle on the ramp lane next to the mainline lanes.

• Activation of the left-turn signal on the vehicle on the ramp intending to merge onto the 

highway (this is not a CARMA program consideration). 

• Execution of the merging maneuver by the vehicle in the ramp acceleration lane. 

All maneuvers by vehicles in the mainline lanes next to the vehicle desiring to merge are 

considered reactions to the merging vehicle. These maneuvers include speeding up or slowing 

down as well as safely merging into the mainline lanes to the left.

Requirements for Merging onto a Highway 

The requirements for merging onto a highway and fulfilling the stated user-operational needs are 

defined in table 6. 

Table 6. Requirements for merging onto a highway. 

Functional 

Requirement 

Identifier Functional Requirement

Applicable to 

CARMA

BT-R1.01 An ADS-equipped vehicle with at least Cooperation Class A capabilities 

shall provide for the capability to avoid crashes with other vehicles (vehicles 

with or without Cooperation Class capabilities) prior to, during, and after 

completion of the merging maneuver. Communications shall be possible 

approximately every 1⁄10 s.

Yes, Cooperation 

Class B and 

higher

BT-R1.02 An ADS-equipped vehicle with at least Cooperation Class A capabilities 

shall be able to broadcast its location, speed, heading, and brake status 

approximately every 1⁄10 s.

Yes, Cooperation

Class B and 

higher

BT-R1.03 An ADS-equipped vehicle with at least Cooperation Class A capabilities 

shall be able to receive, decode, process, analyze, and use locations, speeds, 

and headings from other ADS-equipped vehicles with at least Cooperation 

Class A within its short-range communications approximately every 1⁄10 s.

Yes, Cooperation

Class B and 

higher

BT-R1.04 An ADS-equipped vehicle with at least Cooperation Class A capabilities 

shall be able to receive, decode, process, analyze, and use braking status 

from other ADS-equipped vehicles with at least Cooperation Class A within 

its short-range communications approximately every 1⁄10 s.

Yes, Cooperation

Class B and 

higher

BT-R1.05 An ADS-equipped vehicle with at least Cooperation Class A capabilities 

shall be able to receive, decode, process, analyze, and use locations, speeds, 

and headings from other ADS-equipped vehicles with at least Cooperation 

Class A via long-range communications within a configurable geofenced 

area approximately every 1⁄10 s.

Optional, 

Cooperation Class 

B and higher

BT-R1.06 An ADS-equipped vehicle with at least Cooperation Class A capabilities 

shall be able to receive, decode, process, analyze, and use braking status 

from other ADS-equipped vehicles with at least Cooperation Class A

capabilities via long-range communications within a configurable geofenced 

area approximately every 1⁄10 s.

Optional, 

Cooperation Class 

B and higher

BT-R1.07 An ADS-equipped vehicle with at least Cooperation Class A capabilities

shall be able to broadcast its driving path for the last 1 min approximately 

every 1 s.

No

BT-R1.08 An ADS-equipped vehicle with at least Cooperation Class B capabilities

shall be able to broadcast its intended future driving path for at least the next 

15 s at intervals of approximately every 3 s.

Yes
29 

Functional 

Requirement 

Identifier Functional Requirement

Applicable to 

CARMA

BT-R1.09 An ADS-equipped vehicle with at least Cooperation Class B capabilities 

shall be able to interpret received intentions to merge onto a highway and 

process these intentions in conjunction with the received locations, speeds, 

headings, and brake status from other ADS-equipped vehicles with 

Cooperation Class A capabilities or higher. 

Yes

BT-R1.10 An ADS-equipped vehicle with Cooperation Class C capabilities shall be 

able to send and receive, decode, process, analyze, and use detailed intention 

data, including ACKs and NAKs when cooperating with other 

ADS-equipped vehicles with Cooperation Class C during the merging 

process. A NAK is defined as a signal that rejects a previously received 

message or indicates an error.

Yes

BT-R1.11 An ADS-equipped vehicle with at least Cooperation Class B capabilities 

shall, upon receipt of merge-intention indications, process this information 

and either speed up (if slightly ahead of a merging vehicle) or slow down 

(if slightly behind a merging vehicle) to make space for a vehicle to merge 

onto a highway.

Yes

BT-R1.12 An ADS-equipped vehicle with no cooperative automation capabilities 

driving on the highway shall be able to determine that it is approaching an 

onramp.

Yes

BT-R1.13 An ADS-equipped vehicle with no cooperative automation capabilities 

driving on an arterial, and desiring to drive onto an intersecting highway, 

shall be able to determine its location and recognize that it is entering and 

driving on a ramp.

No

BT-R1.14 An ADS-equipped vehicle with no cooperative automation capabilities shall 

be able to use onboard sensors to detect the location, speed, and heading at 

suitable sensing intervals of non-ADS-equipped vehicles without 

Cooperation Class capabilities within its vicinity.

Yes

BT-R1.15 An ADS-equipped vehicle with at least Cooperation Class A capabilities

shall be able to detect the turn-signal status of a non-ADS equipped vehicle 

without Cooperation Class capabilities (assuming there is a clear line of 

sight).

No

BT-R1.16 An ADS-equipped vehicle shall have a way to visually display to the driver 

the location of other vehicles about which it has information.

Optional

BT-R1.17 A TMS shall be able to receive aggregated data (e.g., locations, speeds, 

headings, and brake status) from each ADS-equipped vehicle with at least 

Cooperation Class A in a specified area. Communications shall be possible 

approximately every 1 s via short- or long-range communications 

infrastructure to the TMS.

Yes

ACK = acknowledgment; NAK = negative acknowledgment.

Performance Metrics

Key performance metrics for monitoring and evaluating operations during execution of this 

situation, some of which were adapted from A Framework for Automated Driving System 

Testable Cases and Scenarios, should include the following: 

• Separation distances—longitudinal distances between the vehicles in the test. Separation 

distances are used to determine safe distances and the frequency of infringement of those 

distances (Thorn et al. 2018). 
30 

• Disengagements—occurrence frequency when safety drivers deactivate the ADS feature 

being tested and take manual control of the vehicles (Thorn et al. 2018). 

• Travel speeds driven—speeds driven by each of the vehicles during the tests will be used 

to create an accurate picture (playback) for evaluating driving within the vehicle travel 

areas.

• Speed change—changes in speeds of the vehicles above or below a specified threshold in 

response to interactions between ADS-equipped vehicles (i.e., reduction in speeds by the 

vehicle on the ramp moving onto the highway and reductions/maintenance of the 

mainline vehicles’ speeds).

• Data exchanges during negotiation (Cooperation Class C)—capture all data exchanges 

between two Cooperation Class C ADS-equipped vehicles to determine whether the 

maneuver negotiations occurred as designed. The data exchanges include the following 

data types:

o Total duration of negotiation process. 

o Frequency of negotiation success/failure (negative acknowledgments [NAKs] from 

neighboring vehicles). 

o Number of attempts before a plan is accepted by all affected neighbors. 

o Message latency. The time difference between vehicle 1 sending the message and 

vehicle 2 reading the message. The latency time includes the time to compose the 

message, sending it from vehicle 1’s guidance computer to vehicle 1’s Onboard Unit 

(OBU), the queuing time on vehicle 1’s OBU, the radio transmission from vehicle 1 

to vehicle 2, the message constitution and queueing on vehicle 2’s OBU, sending the 

message from vehicle 2’s OBU to vehicle 2’s guidance computer, and the time for 

vehicle 2’s decomposition and reading time. 

Requirements Traceability Matrix for Operational Needs and Functional Requirements

Table 7 traces the relationship between operational needs and functional requirements. 
31 

Table 7. Requirements traceability matrix for merging onto a highway. 

Operational 

Need

Identifier Operational Need

Functional 

Requirement

Identifier Functional Requirement

BT-N1.01 Improve safety and 

efficiency of highway 

merge maneuvers.

BT-R1.01 An ADS-equipped vehicle with at least Cooperation 

Class A capabilities shall provide for the capability 

to avoid crashes with other vehicles (vehicles with or 

without Cooperation Class capabilities) prior to, 

during, and after completion of the merging 

maneuver. Communications shall be possible 

approximately every 1⁄10 s. 

BT-N1.02 Maintain situational 

awareness during 

merging operations.

BT-R1.02 An ADS-equipped vehicle with at least Cooperation 

Class A capabilities shall be able to broadcast its 

location, speed, heading, and brake status at 

approximately every 1⁄10 s.

BT-N1.02 Maintain situational 

awareness during 

merging operations.

BT-R1.03 An ADS-equipped vehicle with at least Cooperation 

Class A capabilities shall be able to receive, decode, 

process, analyze, and use locations, speeds, and 

headings from other ADS-equipped vehicles with at 

least Cooperation Class A within its short-range 

communications range approximately every 1⁄10 s.

BT-N1.02 Maintain situational 

awareness during 

merging operations.

BT-R1.04 An ADS-equipped vehicle with at least Cooperation 

Class A capabilities shall be able to receive, decode, 

process, analyze, and use braking status from other 

ADS-equipped vehicles with at least Cooperation 

Class A capabilities within its short-range 

communications range approximately every 1⁄10 s.

BT-N1.02 Maintain situational 

awareness during 

merging operations.

BT-R1.05 An ADS-equipped vehicle with at least Cooperation 

Class A capabilities shall be able to receive, decode, 

process, analyze, and use locations, speeds, and 

headings from other ADS-equipped vehicles with at 

least Cooperation Class A capabilities via long-range 

communications within a configurable geofenced 

area approximately every 1⁄10 s.

BT-N1.02 Maintain situational 

awareness during 

merging operations.

BT-R1.06 An ADS-equipped vehicle with at least Cooperation 

Class A capabilities shall be able to receive, decode, 

process, analyze, and use braking status from other 

ADS-equipped vehicles with at least Cooperation 

Class A capabilities via long-range communications 

within a configurable geofenced area approximately 

every 1⁄10 s.

BT-N1.02 Maintain situational 

awareness during 

merging operations.

BT-R1.07 An ADS-equipped vehicle with at least Cooperation 

Class B capabilities shall be able to broadcast its 

driving path for the last 1 min approximately every 

1 s. 

BT-N1.02 Maintain situational 

awareness during 

merging operations.

BT-R1.12 An ADS-equipped vehicle with no cooperative 

automation capabilities driving on the highway shall 

be able to determine that it is approaching an 

onramp.

BT-N1.02 Maintain situational 

awareness during 

merging operations.

BT-R1.13 An ADS-equipped vehicle with no cooperative 

automation capabilities driving on an arterial, and 

desiring to drive onto an intersecting highway, shall 

be able to determine its location and recognize that it 

is entering and driving on a ramp. 
32 

Operational 

Need

Identifier Operational Need

Functional 

Requirement

Identifier Functional Requirement

BT-N1.02 Maintain situational 

awareness during 

merging operations.

BT-R1.14 An ADS-equipped vehicle with no cooperative 

automation capabilities shall be able to use onboard 

sensors to detect non-ADS-equipped vehicles 

without Cooperation Class capabilities within its 

vicinity, including the vehicle’s location, speed, and 

heading at suitable sensing intervals.

BT-N1.02 Maintain situational 

awareness during 

merging operations.

BT-R1.15 An ADS-equipped vehicle with at least Cooperation 

Class A capabilities shall be able to detect the 

turn-signal status of a non-ADS-equipped vehicle 

without Cooperation Class capabilities (assuming 

there is a clear line of sight).

BT-N1.03 Ability to gather, 

integrate, process, and 

disseminate data.

BT-R1.02 An ADS-equipped vehicle with at least Cooperation 

Class A capabilities shall be able to broadcast its 

location, speed, heading, and brake status 

approximately every 1⁄10 s. 

BT-N1.03 Ability to gather, 

integrate, process, and 

disseminate data.

BT-R1.03 An ADS-equipped vehicle with at least Cooperation 

Class A capabilities shall be able to receive, decode, 

process, analyze, and use locations, speeds, and 

headings from other ADS-equipped vehicles with at 

least Cooperation Class A capabilities within its 

short-range communications range approximately 

every 1⁄10 s.

BT-N1.03 Ability to gather, 

integrate, process, and 

disseminate data.

BT-R1.04 An ADS-equipped vehicle with at least Cooperation 

Class A capabilities shall be able to receive, decode, 

process, analyze, and use braking status from other 

ADS-equipped vehicles with at least Cooperation 

Class A capabilities within its short-range 

communications range approximately every 1⁄10 s.

BT-N1.03 Ability to gather, 

integrate, process, and 

disseminate data.

BT-R1.05 An ADS-equipped vehicle with at least Cooperation 

Class A capabilities shall be able to receive, decode, 

process, analyze, and use locations, speeds, and 

headings from other ADS-equipped vehicles with at 

least Cooperation Class A capabilities via long-range

communications within a configurable geofenced 

area approximately every 1⁄10 s.

BT-N1.03 Ability to gather, 

integrate, process, and 

disseminate data.

BT-R1.06 An ADS-equipped vehicle with at least Cooperation 

Class A capabilities shall be able to receive, decode, 

process, analyze, and use braking status from other 

ADS-equipped vehicles with at least Cooperation 

Class A capabilities via long-range communications 

within a configurable geofenced area approximately 

every 1⁄10 s.

BT-N1.03 Ability to gather, 

integrate, process, and 

disseminate data.

BT-R1.07 An ADS-equipped vehicle with at least Cooperation 

Class A capabilities shall be able to broadcast its 

driving path for the last 1 min approximately every 

1 s.

BT-N1.03 Ability to gather, 

integrate, process, and 

disseminate data.

BT-R1.08 An ADS-equipped vehicle with at least Cooperation 

Class B capabilities shall be able to broadcast its 

intended future driving path for at least the next 15 s

at intervals of approximately every 3 s.
33 

Operational 

Need

Identifier Operational Need

Functional 

Requirement

Identifier Functional Requirement

BT-N1.03 Ability to gather, 

integrate, process, and 

disseminate data.

BT-R1.09 An ADS-equipped vehicle with at least Cooperation 

Class B capabilities shall be able to interpret received 

intentions to merge onto a highway and process these 

intentions in conjunction with the received locations, 

speeds, headings, and brake status from other 

ADS-equipped vehicles with Cooperation Class A

capabilities or higher. 

BT-N1.03 Ability to gather, 

integrate, process, and 

disseminate data.

BT-R1.10 An ADS-equipped vehicle with Cooperation Class C

capabilities shall be able to send, receive, decode, 

process, analyze, and use detailed intention data 

including ACKs and NAKs when cooperating with 

other ADS-equipped vehicles with Cooperation 

Class C capabilities during the merging process.

BT-N1.04 Need for location and 

speed information from 

vehicles near the 

ADS-equipped vehicle.

BT-R1.03 An ADS-equipped vehicle with at least Cooperation 

Class A capabilities shall be able to receive, decode, 

process, analyze, and use locations, speeds, and 

headings from other ADS-equipped vehicles with at 

least Cooperation Class A capabilities within its 

short-range communications approximately every 

1⁄10 s.

BT-N1.04 Location and speed 

information from 

vehicles near the 

ADS-equipped vehicle.

BT-R1.04 An ADS-equipped vehicle with at least Cooperation 

Class A capabilities shall be able to receive, decode, 

process, analyze, and use braking status from other 

ADS-equipped vehicles with at least Cooperation 

Class A capabilities within its short-range 

communications range approximately every 1⁄10 s.

BT-N1.04 Location and speed 

information from 

vehicles near the 

ADS-equipped vehicle.

BT-R1.05 An ADS-equipped vehicle with at least Cooperation 

Class A capabilities shall be able to receive, decode, 

process, analyze, and use locations, speeds, and 

headings from other ADS-equipped vehicles with at 

least Cooperation Class A capabilities via long-range 

communications within a configurable geofenced 

area approximately every 1⁄10 s.

BT-N1.04 Location and speed 

information from 

vehicles near the 

ADS-equipped vehicle.

BT-R1.06 An ADS-equipped vehicle with at least Cooperation 

Class A capabilities shall be able to receive, decode, 

process, analyze, and use braking status from other 

ADS-equipped vehicles with at least Cooperation 

Class A capabilities via long-range communications 

within a configurable geofenced area approximately 

every 1⁄10 s. 

BT-N1.05 Merging vehicle speeds, 

locations, and braking 

information from 

neighboring vehicles.

BT-R1.03 An ADS-equipped vehicle with at least Cooperation 

Class A capabilities shall be able to receive, decode, 

process, analyze, and use locations, speeds, and 

headings from other ADS-equipped vehicles with at 

least Cooperation Class A capabilities within its 

short-range communications range approximately 

every 1⁄10 s.
34 

Operational 

Need

Identifier Operational Need

Functional 

Requirement

Identifier Functional Requirement

BT-N1.05 Merging vehicle speeds, 

locations, and braking 

information from 

neighboring vehicles.

BT-R1.04 An ADS-equipped vehicle with at least Cooperation 

Class A capabilities shall be able to receive, decode, 

process, analyze, and use braking status from other 

ADS-equipped vehicles with at least Cooperation 

Class A capabilities within its short-range 

communications range approximately every 1⁄10 s.

BT-N1.05 Merging vehicle speeds, 

locations, and braking 

information from 

neighboring vehicles.

BT-R1.05 An ADS-equipped vehicle with at least Cooperation 

Class A capabilities shall be able to receive, decode, 

process, analyze, and use locations, speeds, and 

headings from other ADS-equipped vehicles with at 

least Cooperation Class A capabilities via long-range 

communications within a configurable geofenced 

area approximately every 1⁄10 s.

BT-N1.05 Merging vehicle speeds, 

locations, and braking 

information from 

neighboring vehicles.

BT-R1.06 An ADS-equipped vehicle with at least Cooperation 

Class A capabilities shall be able to receive, decode, 

process, analyze, and use braking status from other 

ADS-equipped vehicles with at least Cooperation 

Class A capabilities via long-range communications 

within a configurable geofenced area approximately 

every 1⁄10 s.

BT-N1.05 Merging vehicle speeds, 

locations, and braking 

information from 

neighboring vehicles.

BT-R1.09 An ADS-equipped vehicle with at least Cooperation 

Class B capabilities shall be able to interpret received 

intentions to merge onto a highway and process these 

intentions in conjunction with the received locations, 

speeds, headings, and brake status from other 

ADS-equipped vehicles with Cooperation Class A

capabilities or higher. 

BT-N1.05 Merging vehicle speeds, 

locations and braking 

information from 

neighboring vehicles.

BT-R1.10 An ADS-equipped vehicle with Cooperation Class C

capabilities shall be able to send and receive, decode, 

process, analyze, and use detailed intention data 

including ACKs and NAKs when cooperating with 

other ADS-equipped vehicles with Cooperation 

Class C capabilities during the merging process.

BT-N1.05 Merging vehicle speeds, 

locations, and braking 

information from 

neighboring vehicles.

BT-R1.14 An ADS-equipped vehicle with no cooperative 

automation capabilities shall be able to use onboard 

sensors to detect the location, speed, and heading at 

suitable sensing intervals of non-ADS-equipped 

vehicles without Cooperation Class capabilities 

within its vicinity.

BT-N1.05 Merging vehicle speeds, 

locations, and braking 

information from 

neighboring vehicles.

BT-R1.15 An ADS-equipped vehicle with at least Cooperation 

Class A capabilities shall be able to detect the 

turn-signal status of a non-ADS-equipped vehicle 

without Cooperation Class capabilities (assuming 

there is a clear line of sight).

BT-N1.06 Main line vehicle speeds, 

locations, and braking 

information from 

neighboring vehicles.

BT-R1.03 An ADS-equipped vehicle with at least Cooperation 

Class A capabilities shall be able to receive, decode, 

process, analyze, and use locations, speeds, and 

headings from other ADS-equipped vehicles with at 

least Cooperation Class A capabilities within the 

vehicle’s short-range communications range 

approximately every 1⁄10 s.
35 

Operational 

Need

Identifier Operational Need

Functional 

Requirement

Identifier Functional Requirement

BT-N1.06 Main line vehicle speeds, 

locations, and braking 

information from 

neighboring vehicles.

BT-R1.04 An ADS-equipped vehicle with at least Cooperation 

Class A capabilities shall be able to receive, decode, 

process, analyze, and use braking status from other 

ADS-equipped vehicles with at least Cooperation 

Class A capabilities within its short-range 

communications approximately every 1⁄10 s. 

BT-N1.06 Main line vehicle speeds, 

locations, and braking 

information from 

neighboring vehicles.

BT-R1.05 An ADS-equipped vehicle with at least Cooperation 

Class A capabilities shall be able to receive, decode, 

process, analyze, and use locations, speeds, and 

headings from other ADS-equipped vehicles with at 

least Cooperation Class A capabilities via long-range 

communications within a configurable geofenced 

area approximately every 1⁄10 s.

BT-N1.06 Main line vehicle speeds,

locations, and braking 

information from 

neighboring vehicles.

BT-R1.06 An ADS-equipped vehicle with at least Cooperation 

Class A capabilities shall be able to receive, decode, 

process, analyze, and use braking status from other 

ADS-equipped vehicles with at least Cooperation 

Class A capabilities via long-range communications 

within a configurable geofenced area approximately 

every 1⁄10 s.

BT-N1.06 Main line vehicle speeds, 

locations, and braking 

information from 

neighboring vehicles.

BT-R1.09 An ADS-equipped vehicle with at least Cooperation 

Class B capabilities shall be able to interpret received 

intentions to merge onto a highway and process these 

intentions in conjunction with the received locations, 

speeds, headings, and brake status from other 

ADS-equipped vehicles with Cooperation Class A

capabilities or higher. 

BT-N1.06 Main line vehicle speeds, 

locations, and braking 

information from 

neighboring vehicles.

BT-R1.10 An ADS-equipped vehicle with Cooperation Class C

capabilities shall be able to send, receive, decode, 

process, analyze, and use detailed intention data, 

including ACKs and NAKs when cooperating with 

other ADS-equipped vehicles with Cooperation 

Class C capabilities during the merging process.

BT-N1.06 Main line vehicle speeds, 

locations, and braking 

information from 

neighboring vehicles.

BT-R1.11 An ADS-equipped vehicle with at least Cooperation

Class B capabilities shall, upon receipt of 

merge-intention indications, process the merge 

information and either speed up if slightly ahead of a 

merging vehicle or slow down if slightly behind a 

merging vehicle to make space for a vehicle to merge 

onto a highway.

BT-N1.07 Detect vehicles incapable 

of cooperating with other 

vehicles.

BT-R1.14 An ADS-equipped vehicle with no cooperative 

automation capabilities shall be able to use onboard 

sensors to detect the location, speed, and heading at 

suitable sensing intervals of non-ADS-equipped 

vehicles without Cooperation Class capabilities 

within its vicinity.

BT-N1.07 Detect vehicles incapable 

of cooperating with other 

vehicles.

BT-R1.15 An ADS-equipped vehicle with no cooperative 

automation capabilities shall be able to detect the 

turn-signal status of a non-ADS-equipped vehicle 

without Cooperation Class capabilities (assuming 

there is a clear line of sight).
36 

Operational 

Need

Identifier Operational Need

Functional 

Requirement

Identifier Functional Requirement

BT-N1.08 Advance information 

regarding approaching 

ramps.

BT-R1.08 An ADS-equipped vehicle with at least Cooperation 

Class B capabilities shall be able to broadcast its 

intended future driving path for at least the next 15 s 

at intervals of approximately every 3 s.

BT-N1.08 Advance information 

regarding approaching 

ramps.

BT-R1.12 An ADS-equipped vehicle with no cooperative 

automation capabilities driving on the highway shall 

be able to determine that it is approaching an 

onramp.

BT-N1.08 Advance information 

regarding approaching 

ramps.

BT-R1.13 An ADS-equipped vehicle with no cooperative 

automation capabilities driving on an arterial and 

desiring to drive onto an intersecting highway shall 

be able to determine its location and recognize that it 

is entering and driving on a ramp.

BT-N1.09 Visual alerts from 

vehicles in the vicinity 

showing intent to merge 

onto the highway.

BT-R1.15 An ADS-equipped vehicle with no cooperative 

automation capabilities shall be able to detect the 

turn-signal status of a non-ADS-equipped vehicle 

without Cooperation Class capabilities (assuming 

there is a clear line of sight).

BT-N1.09 Visual alerts from 

vehicles in the vicinity 

showing intent to merge 

onto the highway

BT-R1.16 An ADS-equipped vehicle shall have a way to 

visually display to the driver the location of other 

vehicles about which it has information.

BT-N1.10 Visual alerts from 

vehicles in the vicinity 

showing intent to allow 

vehicle merge from 

onramp onto the 

highway.

BT-R1.09 An ADS-equipped vehicle with at least Cooperation 

Class B capabilities shall be able to interpret received 

intentions to merge onto a highway and process these 

intentions in conjunction with the received locations, 

speeds, headings, and brake status from other 

ADS-equipped vehicles with Cooperation Class A

capabilities or higher. 

BT-N1.10 Visual alerts from 

vehicles in the vicinity 

showing intent to allow 

vehicle merge from 

onramp onto the 

highway.

BT-R1.10 An ADS-equipped vehicle with Cooperation Class C

capabilities shall be able to send, receive, decode, 

process, analyze, and use detailed intention data 

including ACKs and NAKs when cooperating with 

other ADS-equipped vehicles with Cooperation 

Class C capabilities during the merging process.

BT-N1.10 Visual alerts from 

vehicles in the vicinity 

showing intent to allow 

vehicle merge from 

onramp onto the 

highway.

BT-R1.16 An ADS-equipped vehicle shall have a way to 

visually display to the driver the location of other 

vehicles about which it has information.

BT-N1.11 Gather and process data 

from ITS devices and 

ADS-equipped vehicles 

to monitor current traffic 

conditions.

BT-R1.17 A TMS shall be able to receive aggregated data 

(e.g., locations, speeds, headings, and brake status) 

from each ADS-equipped vehicle with at least 

Cooperation Class A capabilities in a specified area. 

Communications shall be possible approximately 

every 1 s via short- or long-range communications 

infrastructure to the TMS.

ACK = acknowledgment. 
37 

CHAPTER 4. USE CASE: TIM

PRIORITY SITUATION 2 TREATMENT: VEHICLE MOVES OUT OF THE WAY OF

AN ADS-EQUIPPED EMERGENCY/FIRST-RESPONDER VEHICLE

The subject of this situational analysis is an ADS feature with a specified ODD that includes 

operation of ADS-equipped vehicles moving out of the way of an ADS-equipped emergency or 

first-responder vehicle as quickly and safely as possible. In this situation, the emergency vehicle 

will be responding to a traffic incident, and the roadway is populated by vehicles of different 

Automation Levels and Cooperation Classes.

The ADS-equipped first-responder vehicle travels through the ADS vehicle travel areas of 

advanced warning/notification, transition, activity, and termination. These travel areas are 

defined in chapter 2. 

Priority situation 2 involves several vehicles positioned relatively close on both lanes of a 

two-lane roadway (for testing this situation, vehicles moving in only one direction of travel will 

be sufficient). A first-responder vehicle responding to an incident approaches the vehicles from 

behind. The incident site and location are irrelevant for this situation. Depending on the location 

and availability of shoulder space, the first-responder vehicle can approach the other vehicles 

from the left or right side or the middle along the direction of travel. For situation 2, the 

emergency vehicle approaches through the middle of the roadway and other vehicles move to the 

left shoulder if traveling in the left lane and to the right shoulder if traveling in the right lane. 

This situation considers several vehicle configurations, including different levels of automation 

and classes of cooperation capabilities among the vehicles.

The situational layout is depicted in figure 14. Circles surround vehicles with different 

Cooperation Class capabilities. The other vehicles in the graphic are not essential for the 

execution of tests of this situation. 

Source: FHWA.

Figure 14. Illustration. Traffic-Incident Management situational layout. 

Operational Needs

Situation 2 is intended to address specific operational user needs, as shown in table 8 through 

table 11. 
38 

Table 8. Operational needs for TIM. 

Operational 

Need 

Identifier Operational Needs 

TIM-N1.01 Nonemergency vehicles move out of the way of emergency vehicles safely and quickly.

TIM-N1.02 Systems gather, integrate, process, and disseminate data.

Table 9. TIM—operational needs for ADS-equipped vehicles.

Operational 

Need 

Identifier Operational Needs for ADS-Equipped Vehicles

TIM-N1.03 Location and speed information from other ADS-equipped vehicles near the first-responder vehicle 

equipped with ADS. 

TIM-N1.04 Location and speed information from first-responder vehicles equipped with ADS near other 

ADS-equipped vehicles.

TIM-N1.05 Trajectory information from first-responder vehicles equipped with ADS. 

TIM-N1.06 Ability to detect vehicles incapable of cooperating with other vehicles.

Table 10. TIM—operational need for non-ADS-equipped vehicles (human driver).

Operational 

Need 

Identifier Operational Need for Non-ADS-Equipped Vehicles (Human Driver)

TIM-N1.07 Visual and audio alerts from approaching first-responder vehicles.

Table 11. TIM—operational needs for TMS. 

Operational 

Need 

Identifier Operational Needs for TMS

TIM-N1.08 Gather and process data from ITS devices and ADS-equipped vehicles to monitor current traffic 

conditions.

TIM-N1.09 Provide traffic and routing information to first-responder vehicles.

Stakeholders and Entities

Researchers can execute the operational situation using several vehicles. The focus of CARMA 

is on Automation Level 3 or higher and Cooperation Class B capabilities or higher, even though 

under real-world conditions, other vehicles will also be encountered that will be equipped with 

lower Automation Levels and Cooperation Classes. The following stakeholders and entities, and 

their associated minimum vehicle configurations, should be considered when executing this 

operational situation within CARMA. The rear vehicle is the second vehicle on the through 

lanes, and the front vehicle is the leading vehicle.

• Test vehicle (vehicle in right lane):

o ADS vehicle with Automation Level 3 and Cooperation Class B. 

• Vehicle 1 (rear) in left lane:

o ADS vehicle with Automation Level 3 and Cooperation Class B. 

• Vehicle 2 (front) in left lane:

o ADS vehicle with Automation Level 3 and Cooperation Class B. 
39 

Another stakeholder is the TMS operator (or software package) that will monitor the positions of 

each vehicle for recording and storage purposes. This situation does not include any field-device 

equipment that needs to be managed; therefore, the TMS operator is passive in this situation. If 

an RSU is used for the communications, then the TMS will need to monitor the communications 

associated with the RSU.

User-Oriented Operational Description

Concept Diagram 

Priority situation 2 includes several ADS-equipped vehicle travel areas—advanced 

warning/notification, transition, activity, and termination—that are explained in detail in the 

following sections. The priority situation concepts include an overview diagram for each 

ADS-equipped vehicle travel area, a description, and a table that shows how vehicles with 

different Automation Levels and Cooperation Classes would react and respond within each travel 

area of the situation shown in figure 8. 

For the following descriptions of ADS-equipped vehicle travel areas used within CARMA, 

researchers assumed that the involved vehicles support at least Cooperation Class B capabilities. 

Advanced Warning/Notification Vehicle Travel Area

Within the advanced warning/notification area, ADS-equipped vehicles travel along a two-lane 

roadway. The vehicles receive a broadcast notifying that an ADS-equipped first-responder 

vehicle is approaching from the rear requesting all vehicles in front move to the outside of their 

respective lanes (i.e., vehicles in the left lane move to the left and vehicles in the right lane move 

to the right) to drive slowly and provide an emergency lane for the first-responder vehicle. The 

ADS-equipped first-responder vehicle could also request that all vehicles move to the right or to 

the left as far as possible. The information from the emergency vehicle includes location, speed, 

heading, and the request to move downstream vehicles out of the way. Figure 15 shows a layout 

of the notification travel area.

Each ADS-equipped vehicle on the two-lane roadway receiving a notification determines, based 

on its own location, its speed and heading, the direction it will have to move (i.e., vehicles in the 

left lane move to the left and vehicles in the right lane move to the right) to accommodate the 

first-responder vehicle, and the approach time of the first-responder vehicle. In this situation, all 

vehicles on the two-lane roadway will be affected.

Source: FHWA.

Figure 15. Illustration. TIM—ADS-equipped vehicles receiving a notification.
40 

Vehicle Travel Transition Area 

Within the transition area, ADS-equipped vehicles drive on the roadway, receive data from the 

approaching first-responder vehicle, and prepare to move out of the way, as shown in figure 16. 

The vehicles also broadcast to each other about their intentions if suitably equipped. This 

information includes location, speed, heading, as well as path-intention data for the direction 

each vehicle will take.

Each ADS-equipped vehicle on the two-lane roadway receiving a notification determines, based 

on its own location, its speed and heading, the direction it will have to move (i.e., vehicles in the 

left lane move to the left and vehicles in the right lane move to the right), and the approach time 

of the first-responder vehicle. In this situation, all vehicles on the two-lane roadway will be 

affected. Vehicles capable of Cooperation Class C exchange data to coordinate the maneuvers 

each vehicle is executing.

Source: FHWA.

Figure 16. Illustration. TIM—vehicle transition area.

Vehicle Travel Activity Area

Within the activity area (figure 17), ADS-equipped vehicles on the two-lane highway have 

moved out of the way (i.e., vehicles in the left lane moved to the left and vehicles in the right 

lane moved to the right) and move slowly or have stopped. They broadcast their current locations 

as well as their intended-path information to each other and to the first-responder vehicle. The 

intended-path information includes location, speed, heading, and brake status for the vehicles in 

the mainline lanes that have slowed or are slowing down or stopped as well as path predictions 

from each vehicle and the first-responder vehicle.

Source: FHWA.

Figure 17. Illustration. TIM—vehicle activity area.
41 

Vehicle Travel Termination Area

Within the termination area, the first-responder vehicle passes ADS-equipped vehicles within the 

two-lane roadway and traffic returns to normal operation along the roadway, as shown in 

figure 18. Normal operations will include coordination among the vehicles to determine the 

sequences and accelerations by each vehicle.

ADS-equipped vehicles in the two-lane roadway must receive data from the ADS-equipped 

first-responder vehicle to indicate that it is passing each specific ADS-vehicle as it passes. 

Source: FHWA.

Figure 18. Illustration. TIM—termination area.

Trigger to Invoke Situation for Vehicles Moving Out of the Way of an ADS-equipped 

Emergency/First Responder Vehicle

Priority situation 2 is triggered by the ADS-equipped first-responder vehicle when approaching 

other ADS-equipped vehicles downstream on the two-lane roadway. The following indicators are 

designated as triggers to invoke responses of mainline vehicles: 

• Broadcast by approaching ADS-equipped first-responder vehicle.

• Activation of flashing lights and sirens on the first-responder vehicle intending to merge 

onto the highway (this is not a CARMA consideration). 

All maneuvers by vehicles in the two-lane roadway in front of the ADS-equipped first-responder 

vehicle are considered reactions to the approaching first-responder vehicle. These maneuvers 

include moving to the shoulders and slowing down or stopping on the nearest shoulder to create 

the first-responder vehicle corridor. 

Requirements for Vehicles Moving out of the Way of an ADS-Equipped 

Emergency/First-Responder Vehicle

The requirements to address priority situation 2 and to fulfill the stated user-operational needs 

are defined in table 12. 
42 

Table 12. Requirements for vehicles moving out of the way of an ADS-equipped 

emergency/first-responder vehicle. 

Functional 

Requirement

Identifier Functional Requirement

Applicable to 

CARMA

TIM-R1.01 An ADS-equipped vehicle with at least Cooperation Class A capabilities shall 

provide for the capability to avoid crashes with other vehicles (vehicles with or 

without Cooperation Class capabilities) prior to, during, and after completion 

of the move-out-of-the-way maneuver. Communications shall be possible 

approximately every 1⁄10 s.

Yes, 

Cooperation

Class B and 

higher

BT-R1.02 See table 6 for the same requirement FR ID number. Yes, 

Cooperation

Class B and 

higher

BT-R1.03 See table 6 for the same requirement FR ID number. Yes, 

Cooperation

Class B and 

higher

BT-R1.04 See table 6 for the same requirement FR ID number. Yes, 

Cooperation

Class B and 

higher

TIM-R1.02 An ADS-equipped first-responder vehicle with at least Cooperation Class B

capabilities shall be able to broadcast a request to move out of the way to other 

ADS-equipped vehicles with at least Cooperation Class B capabilities within 

the first responder vehicle’s short-range communications approximately every 

1⁄10 s.

Yes, 

Cooperation

Class B and 

higher

TIM-R1.03 An ADS-equipped vehicle with at least Cooperation Class B capabilities shall 

be able to receive, decode, process, analyze, and react to a request to move out 

of the way from ADS-equipped first-responder vehicles with at least 

Cooperation Class B capabilities within the vehicle’s short-range 

communications approximately every 1⁄10 s.

Yes, 

Cooperation

Class B and 

higher

TIM-R1.04 An ADS-equipped first-responder vehicle with at least Cooperation Class B

capabilities shall be able to send the geofenced area around it to indicate the 

move-out-of-the-way request and lane request to the CARMA CloudSM

approximately every 1 s.

Yes, 

Cooperation

Class B and 

higher

TIM-R1.05 CARMA Cloud shall be able to broadcast the first-responder vehicle’s 

geofencing area to the physical geofenced area approximately every 1 s.

Yes

TIM-R1.06 A request to move out of the way shall include the following: 

• Projected path for the next 30 s (in front of first-responder vehicle 

from vehicle position on the way to incident site). 

• Geofenced area in front of the first-responder vehicle to which the 

move-out-of-the-way request applies.

• Time stamp of when message was first sent. 

Yes

TIM-R1.07 An ADS-equipped first-responder vehicle with at least Cooperation Class B

capabilities shall be able to broadcast a request to turn off the geofence to other 

ADS-equipped vehicles with at least Cooperation Class B capabilities within

the ADS-equipped first-responder vehicle’s short-range communications 

approximately every 1 s.

Yes, 

Cooperation

Class B and 

higher

TIM-R1.08 An ADS-equipped vehicle with at least Cooperation Class B capabilities shall 

be able to receive, decode, process, analyze, and react to a request to turn off 

the geofence from vehicles with at least Cooperation Class B capabilities 

within the ADS-equipped vehicle’s short-range communications

approximately every 1 s.

Yes, 

Cooperation

Class B and 

higher
43 

Functional 

Requirement

Identifier Functional Requirement

Applicable to 

CARMA

BT-R1.05 See table 6 for the same requirement FR ID number. Optional, 

Cooperation

Class B and 

higher

BT-R1.06 See table 6 for the same requirement FR ID number. Optional, 

Cooperation

Class B and 

higher

TIM-R1.09 An ADS-equipped first-responder vehicle with at least Cooperation Class B

capabilities shall be able to broadcast a request to move out of the way to other 

ADS-equipped vehicles with at least Cooperation Class B capabilities within 

its long-range communications approximately every 1⁄10 s.

Optional, 

Cooperation

Class B and 

higher

TIM-R1.10 An ADS-equipped vehicle with at least Cooperation Class B capabilities shall 

be able to receive, decode, process, analyze, and react to a request to move out 

of the way from ADS-equipped first-responder vehicles with at least 

Cooperation Class B within its long-range communications approximately 

every 1⁄10 s.

Optional, 

Cooperation

Class B and 

higher

TIM-R1.11 An ADS-equipped vehicle with at least Cooperation Class A capabilities shall 

be able to broadcast its driving path for the vehicle’s previous one minute of 

travel approximately every 1 s.

No

TIM-R1.12 An ADS-equipped vehicle with at least Cooperation Class B capabilities shall 

be able to broadcast its intended future driving path for at least the next 15 s 

approximately every 3 s.

Yes

TIM-R1.13 An ADS-equipped vehicle with at least Cooperation Class B capabilities shall 

be able to interpret received intentions to create a first-responder emergency 

corridor (i.e., vehicles in the left lane moved to the left and vehicles in the right 

lane moved to the right) and process these intentions in conjunction with the 

received locations, speeds, headings, and brake status from other 

ADS-equipped vehicles with Cooperation Class A capabilities or higher. 

Yes

TIM-R1.14 An ADS-equipped vehicle with Cooperation Class C capabilities shall be able 

to send and receive, decode, process, analyze, and use detailed intention data 

including ACKs and NAKs when cooperating with other nonemergency 

ADS-equipped vehicles with cooperation Class C capabilities during the 

move-over driving process.

Yes

TIM-R1.15 An ADS-equipped vehicle with at least Cooperation Class B capabilities shall 

be able to generate and send a NAK to the broadcasting first-responder vehicle 

within its short-range communications approximately every 1 s if it cannot 

move out the way of the first-responder vehicle.

Yes

TIM-R1.16 An ADS-equipped vehicle with at least Cooperation Class B capabilities shall, 

upon receipt of move-over intention indications, process this information to 

move out of the first-responder vehicle’s path and find its own space on the 

road.

Yes

TIM-R1.17 An ADS-equipped first-responder vehicle with at least Cooperation Class A

capabilities approaching other downstream vehicles shall be able to determine 

that downstream vehicles of all Cooperation Classes (no cooperative 

automation and higher) are moving out of the way.

Yes

TIM-R1.18 An ADS-equipped vehicle shall be able to use onboard sensors to detect the 

location, speed, and heading at suitable sensing intervals of vehicles not 

equipped with ADS in its vicinity. 

Yes

TIM-R1.19 An ADS-equipped vehicle shall be able to detect the turn signal status of a 

vehicle without ADS (without cooperation class capabilities) (assuming there 

is a clear line of sight).

No
44 

Functional 

Requirement

Identifier Functional Requirement

Applicable to 

CARMA

BT-R1.16 See table 6 for the same requirement FR ID number. Optional

TIM-R1.20 An ADS-equipped first-responder vehicle with at least Cooperation Class B

capabilities shall be able to determine that it has passed other vehicles and 

broadcast to other ADS-equipped vehicles with at least Cooperation Class B

capabilities within its short-range communications approximately every 1 s 

that the request to move out of the way has been rescinded.

Yes, 

Cooperation

Class B and 

higher

TIM-R1.21 Any ADS-equipped and non-ADS-equipped vehicle with at least Cooperation 

Class A capabilities shall be able to receive, decode, process, analyze, and use 

the notification from the ADS-equipped first-responder vehicle that it has 

passed the ADS-equipped vehicle and use that information to determine how it 

can safely and efficiently resume its previous travel.

Yes, 

Cooperation

Class B and 

higher

TIM-R1.22 An ADS-equipped first-responder vehicle with at least Cooperation Class B

capabilities shall be able to determine that it has passed other vehicles and 

broadcast to other ADS-equipped vehicles with at least Cooperation Class B

within its long-range communications range approximately every 1 s that the 

request to move out of the way has been rescinded.

Optional

TIM-R1.23 A TMS shall be able to receive aggregated data (e.g., minimum location, 

speed, heading, and brake status) from each ADS-equipped vehicle with at 

least Cooperation Class A capabilities in a specified area. Communications 

shall be possible approximately every 1 s via short- or long-range 

communications infrastructure to the TMS.

Yes 

ACK = acknowledgment; FR ID = functional requirement identification. 

Performance Metrics

Key performance metrics for monitoring and evaluating operations during execution of this 

situation, some of which were adapted from A Framework for Automated Driving System 

Testable Cases and Scenarios, should include the following: 

• Disengagements—occurrence frequency when safety drivers deactivate the ADS feature 

being tested and take manual control of the vehicles (Thorn et al. 2018). 

• Speed changes—changes in vehicle speeds above or below a specified threshold in 

response to interactions between ADS-equipped vehicles and an ADS-equipped 

emergency vehicle (i.e., reductions in speeds by the vehicles moving out of the way and 

reductions/maintenance of the emergency speeds). 

• Move-over time—time for vehicles to safely move out of the way of the ADS-equipped 

emergency vehicle and slow down or stop after receiving the intent or trajectory 

information from the ADS-equipped emergency vehicle.

• Data exchanges during negotiation (Cooperation Class C)—capture all data exchanges 

between two Cooperation Class C ADS-equipped vehicles to determine whether the 

maneuver negotiations took place as designed. The data exchanges include the following 

data types:

o Total duration of negotiation process. 

o Frequency of negotiation success/failure (NAKs from neighboring vehicles). 

o Number of attempts before a plan is accepted by all affected neighbors. 

o Message latency. The time difference between message origination on the emergency 

vehicle to vehicle A’s reading of the message. The latency time includes the time to 

compose the message, sending it from the emergency vehicle’s guidance computer to 
45 

its OBU, the queuing time on its OBU, the radio transmission from the emergency 

vehicle to vehicle A, the message constitution and queueing on vehicle A’s OBU, 

sending it from vehicle A’s OBU to vehicle A’s guidance computer, and the time for 

vehicle A’s decomposition and reading of the message. 

Requirements Traceability Matrix for TIM Operational Needs and Functional 

Requirements

Table 13 traces the relationship between operational needs and functional requirements. 

Table 13. Requirements traceability matrix for vehicles moving out of the way of an 

ADS-equipped emergency/first-responder vehicle.

Operational 

Needs

Identifier Operational Need

Functional 

Requirement 

Identifier Functional Requirement

TIM-N1.01 Nonemergency vehicles 

move out of the way of 

emergency vehicles 

safely and quickly.

TIM-R1.01 An ADS-equipped vehicle with at least Cooperation 

Class A capabilities shall provide for the ability to 

avoid crashes with other vehicles (vehicles with or 

without cooperation class capabilities) prior to, during, 

and after completion of the move-out-of-the-way 

maneuver. Communications shall be possible 

approximately every 1⁄10 s.

TIM-N1.02 Gather, integrate, 

process, and disseminate 

data.

BT-R1.02 An ADS-equipped vehicle with at least Cooperation 

Class A capabilities shall be able to broadcast its 

location, speed, heading, and brake status 

approximately every 1⁄10 s.

TIM-N1.02 Gather, integrate, 

process, and disseminate 

data.

BT-R1.03 An ADS-equipped vehicle with at least Cooperation 

Class A capabilities shall be able to receive, decode, 

process, analyze, and use locations, speeds, and 

headings from other ADS-equipped vehicles with at 

least Cooperation Class A capabilities within its 

short-range communications approximately every 

1⁄10 s.

TIM-N1.02 Gather, integrate, 

process, and disseminate 

data.

BT-R1.04 An ADS-equipped vehicle with at least Cooperation 

Class A capabilities shall be able to receive, decode, 

process, analyze, and use braking status from other 

ADS-equipped vehicles with at least Cooperation 

Class A capabilities within its short-range 

communications approximately every 1⁄10 s.

TIM-N1.02 Gather, integrate, 

process, and disseminate 

data.

TIM-R1.02 An ADS-equipped first-responder vehicle with at least 

Cooperation Class B capabilities shall be able to 

broadcast a request to move out of the way to other 

ADS-equipped vehicles with at least Cooperation 

Class B capabilities within its short-range 

communications approximately every 1⁄10 s.

TIM-N1.02 Gather, integrate, 

process, and disseminate 

data.

TIM-R1.03 An ADS-equipped vehicle with at least Cooperation 

Class B capabilities shall be able to receive, decode, 

process, analyze, and react to a request to move out of 

the way from ADS first-responder vehicles with at 

least Cooperation Class B capabilities within its 

short-range communications approximately every 

1⁄10 s.
46 

Operational 

Needs

Identifier Operational Need

Functional 

Requirement 

Identifier Functional Requirement

TIM-N1.02 Gather, integrate, 

process, and disseminate 

data.

TIM-R1.04 An ADS-equipped first-responder vehicle with at least 

Cooperation Class B capabilities shall be able to send 

the geofenced area around it that indicates the 

move-out-of-the-way direction and lane request to 

CARMA Cloud approximately every 1 s.

TIM-N1.02 Gather, integrate, 

process, and disseminate 

data.

TIM-R1.05 CARMA Cloud shall be able to broadcast the 

first-responder vehicle’s geofencing area to the 

physical geofenced area approximately every 1 s.

TIM-N1.02 Gather, integrate, 

process, and disseminate 

data.

TIM-R1.06 A move-out-of-the-way request shall include the 

following: 

• Projected path for the next 30 s (the path in front 

of first-responder vehicle from vehicle position 

on the way to incident site). 

• Geofenced area in front of the first-responder 

vehicle to which the move-out-of-the-way request 

applies.

• Time stamp of when message was first sent. 

TIM-N1.02 Gather, integrate, 

process, and disseminate 

data.

TIM-R1.07 An ADS-equipped first-responder vehicle with at least 

Cooperation Class B capabilities shall be able to 

broadcast a request to turn off the geofence to other 

ADS-equipped vehicles with at least Cooperation 

Class B capabilities within its short-range 

communications approximately every 1 s.

TIM-N1.02 Gather, integrate, 

process, and disseminate 

data.

TIM-R1.08 An ADS-equipped vehicle with at least Cooperation 

Class B capabilities shall be able to receive, decode, 

process, analyze, and react to a request to turn off the 

geofence from ADS-equipped vehicles with at least 

Cooperation Class B capabilities within the 

ADS-equipped vehicle’s short-range communications 

approximately every 1 s. 

TIM-N1.02 Gather, integrate, 

process, and disseminate 

data.

TIM-R1.09 An ADS-equipped first-responder vehicle with at least 

Cooperation Class B capabilities shall be able to 

broadcast a move-out-of-the-way request to other 

ADS-equipped vehicles with at least Cooperation 

Class B capabilities within its long-range 

communications approximately every 1⁄10 s.

TIM-N1.02 Gather, integrate, 

process, and disseminate 

data.

TIM-R1.10 An ADS-equipped vehicle with at least Cooperation 

Class B capabilities shall be able to receive, decode, 

process, analyze, and react to a request to move out of 

the way from ADS-equipped first-responder vehicles 

with at least Cooperation Class B within its long-range 

communications approximately every 1⁄10 s.

TIM-N1.02 Gather, integrate, 

process, and disseminate 

data.

TIM-R1.11 An ADS-equipped vehicle with at least Cooperation 

Class A capabilities shall be able to broadcast its 

driving path for the previous 1 minute of travel

approximately every 1 s.

TIM-N1.02 Gather, integrate, 

process, and disseminate 

data.

TIM-R1.12 An ADS-equipped vehicle with at least Cooperation 

Class B capabilities shall be able to broadcast its 

intended future driving path for at least the next 15 s 

approximately every 3 s. 
47 

Operational 

Needs

Identifier Operational Need

Functional 

Requirement 

Identifier Functional Requirement

TIM-N1.03 Location and speed 

information from other 

ADS-equipped vehicles 

near ADS-equipped 

first-responder vehicles.

BT-R1.02 An ADS-equipped vehicle with at least Cooperation 

Class A capabilities shall be able to broadcast its 

location, speed, heading, and brake status 

approximately every 1⁄10 s.

TIM-N1.03 Location and speed 

information from other 

ADS-equipped vehicles 

near ADS-equipped 

first-responder vehicles.

BT-R1.03 An ADS-equipped vehicle with at least Cooperation 

Class A capabilities shall be able to receive, decode, 

process, analyze, and use locations, speeds, and 

headings from other ADS-equipped vehicles with at 

least Cooperation Class A capabilities within its 

short-range communications approximately every 

1⁄10 s.

TIM-N1.03 Location and speed 

information from other 

ADS-equipped vehicles 

near ADS-equipped 

first-responder vehicles.

BT-R1.05 An ADS-equipped vehicle with at least Cooperation 

Class A capabilities shall be able to receive, decode, 

process, analyze, and use locations, speeds, and 

headings from other ADS-equipped vehicles with at 

least Cooperation Class A via long-range 

communications within a configurable geofenced area 

approximately every 1⁄10 s. 

TIM-N1.04 Location and speed 

information from 

ADS-equipped 

first-responder vehicles 

near other 

ADS-equipped vehicles.

BT-R1.02 An ADS-equipped with at least Cooperation Class A

capabilities shall be able to broadcast its location, 

speed, heading, and brake status approximately every 

1⁄10 s.

TIM-N1.04 Location and speed 

information from 

ADS-equipped 

first-responder vehicles 

near other ADSequipped vehicles.

BT-R1.03 An ADS-equipped vehicle with at least Cooperation 

Class A capabilities shall be able to receive, decode, 

process, analyze, and use locations, speeds, and 

headings from other ADS-equipped vehicles with at 

least Cooperation Class A within its short-range 

communications approximately every 1⁄10 s.

TIM-N1.04 Location and speed 

information from 

ADS-equipped 

first-responder vehicles 

near other ADSequipped vehicles.

BT-R1.05 An ADS-equipped vehicle with at least Cooperation 

Class A capabilities shall be able to receive, decode, 

process, analyze, and use locations, speeds, and 

headings from other ADS-equipped vehicles with at 

least Cooperation Class A capabilities via long-range 

communications within a configurable geofenced area 

approximately every 1⁄10 s. 

TIM-N1.05 Trajectory information 

from ADS-equipped 

first-responder vehicle.

TIM-R1.09 An ADS-equipped vehicle with at least Cooperation 

Class B capabilities shall be able to broadcast a 

move-out-of-the-way request to other ADS-equipped

vehicles with at least Cooperation Class B capabilities 

within its long-range communications approximately 

every 1⁄10 s. 

TIM-N1.05 Trajectory information 

from ADS-equipped 

first-responder vehicle.

TIM-R1.17 An ADS-equipped first-responder vehicle with at least 

Cooperation Class A capabilities approaching other 

downstream vehicles shall be able to determine that 

downstream vehicles of all Cooperation Classes 

(no cooperative automation and higher) are moving 

out of the way.
48 

Operational 

Needs

Identifier Operational Need

Functional 

Requirement 

Identifier Functional Requirement

TIM-N1.05 Trajectory information 

from ADS-equipped 

first-responder vehicle.

TIM-R1.20 An ADS-equipped first-responder vehicle with at least 

Cooperation Class B capabilities shall be able to 

determine that it has passed other vehicles and 

broadcast to these other ADS-equipped vehicles with 

at least Cooperation Class B capabilities within its 

short-range communications approximately every 1 s 

that the move-out-of-the-way request has been 

rescinded.

TIM-N1.06 Detect vehicles 

incapable of cooperating 

with other vehicles.

TIM-R1.18 An ADS-equipped vehicle shall be able to use 

onboard sensors to detect the location, speed, and 

heading at suitable sensing intervals of non-ADSequipped vehicles.

TIM-N1.06 Ability to detect vehicles 

incapable of cooperating 

with other vehicles.

TIM-R1.19 An ADS-equipped vehicle shall be able to detect the 

turn-signal status of a non-ADS-equipped vehicle 

without cooperation class capabilities (assuming there 

is a clear line of sight).

TIM-N1.06 Detect vehicles 

incapable of cooperating 

with other vehicles. 

BT-R1.16 An ADS-equipped vehicle shall have a means to 

visually display to the driver of another ADSequipped vehicle the location of other vehicles about 

which it has information.

TIM-N1.07 Visual and audio alerts 

from approaching 

first-responder vehicles.

TIM-R1.13 An ADS-equipped vehicle with at least Cooperation 

Class B capabilities shall be able to interpret received 

intentions to create a first-responder emergency 

corridor (vehicles in the left lane move to the left and 

vehicles in the right lane move to the right) and 

process these intentions in conjunction with the 

received locations, speeds, headings, and brake status 

from other ADS-equipped vehicles with Cooperation 

Class A capabilities or higher. 

TIM-N1.07 Visual and audio alerts 

from approaching 

first-responder vehicles.

TIM-R1.14 An ADS-equipped vehicle with Cooperation Class C

capabilities shall be able to send and receive, decode, 

process, analyze, and use detailed intention data, 

including ACKs and NAKs when cooperating with 

other nonemergency ADS-equipped vehicles with 

Cooperation Class C capabilities during the 

move-over driving process.

TIM-N1.07 Visual and audio alerts 

from approaching 

first-responder vehicles.

TIM-R1.15 An ADS-equipped vehicle with at least Cooperation 

Class B capabilities shall be able to generate and send 

a NAK to the broadcasting first-responder vehicle 

within its short-range communications approximately 

every 1 s if it cannot move out the way of the 

first-responder vehicle. 

TIM-N1.07 Visual and audio alerts 

from approaching 

first-responder vehicles.

TIM-R1.16 An ADS-equipped vehicle with at least Cooperation 

Class B capabilities shall, upon receipt of move-over 

intention indications, process this information to move 

out of the first-responder vehicle’s path and find its 

own space on the road.
49 

Operational 

Needs

Identifier Operational Need

Functional 

Requirement 

Identifier Functional Requirement

TIM-N1.08 Gather and process data 

from ITS devices and 

ADS-equipped vehicles 

to monitor current traffic 

conditions. 

TIM-R1.21 Any ADS-equipped and non-ADS-equipped vehicle 

with at least Cooperation Class A capabilities shall be 

able to receive, decode, process, analyze, and use the 

notification from the ADS-equipped first-responder 

vehicle that it has passed the ADS-equipped vehicle 

and use that information to determine how it can 

safely and efficiently resume its previous travel.

TIM-N1.08 Gather and process data 

from ITS devices and 

ADS-equipped vehicles 

to monitor current traffic 

conditions. 

TIM-R1.22 An ADS-equipped first-responder vehicle with at least 

Cooperation Class B capabilities shall be able to 

determine that it has passed other vehicles and 

broadcast to other ADS-equipped vehicles with at 

least Cooperation Class B capabilities within its longrange communications approximately every 1 s that 

the request to move out of the way has been rescinded.

TIM-N1.08 Gather and process data 

from ITS devices and 

ADS-equipped vehicles 

to monitor current traffic 

conditions. 

BT-R1.17 A TMS shall be able to receive aggregated data 

(e.g., location, speed, heading, and brake status) from 

each ADS-equipped vehicle with at least Cooperation 

Class A capabilities in a specified area. 

Communications shall be possible approximately 

every 1 s via short- or long-range communications 

infrastructure to the TMS.

TIM-N1.09 Provide traffic and 

routing information to 

first-responder vehicles.

TIM-R1.23 A TMS shall be able to receive aggregated data 

(e.g., location, speed, heading, and brake status) from 

each ADS-equipped vehicle with at least Cooperation 

Class A capabilities in a specified area. 

Communications shall be possible every 1 s via shortor long-range communications infrastructure to the 

TMS.

ACK = acknowledgment.

51 

CHAPTER 5. USE CASE: RWM

PRIORITY SITUATION 3 TREATMENT: ADS-EQUIPPED VEHICLES SLOW

DOWN/INCREASE GAP WHEN PASSING OVER WET PAVEMENT

The subject of this situational analysis is an ADS feature with a specified ODD that includes 

operation of ADS-equipped vehicles passing over wet pavement as safely as possible. 

Researchers sought at least one vehicle equipped with the appropriate onboard sensors to detect 

weather conditions (e.g., wet pavement, ice, and black ice) on the roadway, as well as surface 

temperatures, which the vehicle can broadcast to other vehicles in its vicinity. CARMA may 

have at least one vehicle that can interface with the vehicle’s Controller Area Network bus to 

obtain, process, and transmit windshield wiper status and antilock braking system (ABS) status. 

The roadway is populated by vehicles of different Automation Levels and Cooperation Classes.

ADS-equipped vehicles travel through the travel areas of advanced warning/notification, 

transition, activity, and termination. These travel areas are defined in chapter 2. 

Priority situation 3 involves several vehicles traveling along a roadway with two lanes in each 

direction approaching a section with wet pavement. The TMS receives information from a road 

weather information system (RWIS) about wet conditions in the area. The TMS creates a 

geofence around the area to transmit this information to ADS-equipped vehicles traveling in both 

directions. The vehicle with onboard weather-sensing equipment also transmits the 

wet-pavement information to vehicles that are upstream and traveling in the opposite direction. 

The vehicles receiving the information slow down and increase the gap between vehicles, called 

headway, to safely pass the wet pavement. A TMS can only provide generic information 

(e.g., reduced speed recommendations, speed limits, and recommended headways) based on 

weather data. The vehicle knows its own conditions (e.g., condition of brakes, loads/weight of 

vehicle), which are factors that might be used to further decrease speeds and increase headways 

for safe vehicle operation. This specific aspect is not currently considered in CARMA but might 

need to be considered in the future. The situational layout is depicted in figure 19. The situation 

includes vehicles with different cooperation class capabilities shown in circles in the graphic. 

The other vehicles in the graphic are not essential for the execution of tests of this situation. 
52 

Source: FHWA.

Figure 19. Illustration. Road Weather Management situational layout. 

Operational Needs

Situation 3 is intended to address specific operational user needs, as presented in table 14

through table 17. 

Table 14. Operational needs for RWM. 

Operational 

Need 

Identifier Operational Need

RWM-N1.01 Safely travel along a roadway impacted by adverse weather.

RWM-N1.02 Gather, integrate, process, and disseminate road weather information.

Table 15. RWM—operational needs for ADS-equipped vehicle systems.

Operational 

Need 

Identifier Operational Needs for ADS-Equipped Vehicle Systems

RWM-N1.03 Identify location and speed information from vehicles near the ADS-equipped vehicle.

RWM-N1.04 Accept and process road weather information (weather data, reduced speed limits, and 

recommended headways) to adjust speed and headway spacing accordingly.

RWM-N1.05 Transmit road weather information to other vehicles.

RWM-N1.06 Detect vehicles incapable of cooperating with other vehicles.

Table 16. RWM—operational needs for non-ADS equipped vehicles (human driver).

Operational 

Need 

Identifier Operational Needs for Non-ADS (Human Driver)

RWM-N1.07 Visual alerts about adverse-weather conditions from ITS devices or radio broadcasts.

RWM-N1.08 Information on acceptable speed limits to safely navigate roadways affected by adverse-weather 

conditions.
53 

Table 17. RWM—operational needs for TMS. 

Operational 

Need 

Identifier Operational Needs for Traffic Management Service

RWM-N1.09 Determine pavement temperature and presence of water, snow, or ice on the roadway.

RWM-N1.10 Provide road weather condition information to ADS-equipped vehicles in a geofenced area.

RWM-N1.11 Provide road weather condition response suggestions (reduced speed limits and recommended 

headways) to ADS-equipped vehicles in a geofenced area.

RWM-N1.12 Gather and process data from ITS devices and ADS-equipped vehicles to monitor current traffic 

conditions.

Stakeholders and Entities

Researchers can execute the operational situation using several vehicles. The focus of CARMA 

is on Automation Level 3 or higher and Cooperation Class B capabilities or higher, but under 

real-world conditions, other vehicles might also be encountered that will only be equipped with 

lower Automation Levels and Cooperation Classes. The following stakeholders and entities and 

their associated minimum vehicle configurations should be considered when executing this 

operational situation within the CARMA program. 

• Weather detection sensor-equipped vehicle (vehicle driving in the opposite direction): 

o ADS vehicle with Automation Level 3 and Cooperation Class B. 

• Vehicle 1 (front): 

o ADS vehicle with Automation Level 3 and Cooperation Class B. 

• Vehicle 2 (rear):

o ADS vehicle with Automation Level 3 and Cooperation Class B. 

Another stakeholder is the TMS operator (or software package), that will monitor the positions 

of each vehicle for recording and storage purposes. The TMS will also receive the data from the 

weather detection sensor-equipped vehicle as well as from roadside weather stations, which it 

will aggregate and broadcast via short- or long-range communications media. If an RSU is used 

for the communications, then the TMS will monitor the communications associated with the 

RSU and send weather information to the RSU for local rebroadcast. 

User-Oriented Operational Description

Concept Diagram 

Situation 3 includes several ADS-equipped vehicle travel areas—advanced warning/notification, 

transition, activity, and termination—that are explained in detail and are suitable for this 

situation. The concepts include an overview diagram for each ADS-equipped vehicle travel area, 

a description, and a table that shows how vehicles with different Automation Levels and 

Cooperation Classes would react and respond within each travel area associated with this 

situation.

For the following descriptions of ADS vehicle travel areas used within CARMA, researchers

assumed that the involved vehicles support at least Cooperation Class B capabilities. 
54 

Advanced Warning/Notification Vehicle Travel Area

Within the advanced warning/notification vehicle travel area, the ADS-equipped vehicles travel 

along a two-lane roadway, during which they all receive a broadcast from the TMS with a 

notification that the downstream area has localized adverse-weather conditions and to be 

prepared to slow down when approaching the affected area. This is shown in figure 20. The 

TMS-provided weather data are based both on roadside weather stations and from information 

from the TMS, which includes a geofenced area (location) at which the RWIS stations and the 

roaming weather-detection vehicle have detected adverse weather, the type of weather impact, 

and the request to prepare to slow down to a suggested speed when arriving at the geofenced 

weather area.

Source: FHWA.

Figure 20. Illustration. RWM—ADS-equipped vehicles receiving a notification.

Vehicle Travel Transition Area

In the transition area, the ADS-equipped vehicles drive along the roadway and continuously 

receive updates to the weather warning messages from the TMS and are prepared to adjust to the 

suggested speeds, as shown in figure 21. 

Vehicles equipped with weather detection sensors are assumed to arrive at the transition area 

from the opposite direction of the weather event and to broadcast the observed weather data to 

the approaching vehicles, just as it did the entire time. These data include the detected start and 

end points of the adverse-weather area (the approaching vehicles will have to invert this 

information), the vehicle’s speed and heading, as well as the type of weather impact. Within 

CARMA, a vehicle will provide windshield wiper and ABS status data to emulate a weather 

event. 

Each ADS-equipped vehicle receiving a notification adjusts its speeds to the suggested speeds by 

the time the vehicle arrives at the start of the geofenced weather-impacted area. In this situation, 

all vehicles on the roadway will be affected.
55 

Source: FHWA.

Figure 21. Illustration. RWM—vehicle transition area. 

Vehicle Travel Activity Area

Within the activity area, the ADS-equipped vehicles on the highway are moving at the suggested 

speed but are always prepared to adjust their speed based on their own sensory assessments 

(e.g., ABS engagement). ADS-equipped vehicles broadcast their current locations, speeds, 

headings, detected weather data (if applicable), and their intended-path information to other 

vehicles in both driving directions, the TMS, and the weather-detecting vehicle driving in the 

opposite direction (if still in range). A layout of the road weather activity area is shown in 

figure 22. 

Source: FHWA.

Figure 22. Illustration. RWM—vehicle activity area. 
56 

Vehicle Travel Termination Area

Within the termination area, the ADS-equipped vehicles reach the end of the weather-affected 

area and return to normal operation along the roadway, as shown in figure 23. Returning to 

normal operation includes increasing driving speeds to safe levels, ultimately up to the posted 

speed limit. ADS-equipped vehicles are broadcasting their locations, current speeds, heading, 

and any current weather-detection readings to other ADS-equipped vehicles in both driving 

directions and the TMS. 

Source: FHWA.

Figure 23. Illustration. RWM—termination area. 

Trigger to Invoke Situation for ADS-Equipped Vehicles Slowing down and Increasing Gap 

When Passing over Wet Pavement

Priority situation 3 is triggered by the TMS and the weather-detecting vehicle sending weather 

warnings and suggested speed data to ADS-equipped vehicles approaching the weather-affected 

geofenced area. The following indicators are designated as triggers to invoke responses of 

ADS-equipped vehicles:

• Broadcast by a TMS.

• Broadcast by vehicles equipped with weather-detection sensors driving in the same, or 

more likely the opposite, direction (within CARMA, a vehicle will provide windshield 

wiper and ABS status data to emulate a weather event).

All maneuvers by vehicles on the roadway are considered reactions to the received weather data 

and suggested speeds when driving through the weather-impacted, geofenced area.

Requirements for ADS-Equipped Vehicles Slowing Down and Increasing Gap When 

Passing Over Wet Pavement 

The requirements to address situation 3 and to fulfill the stated user-operational needs are 

defined in table 18. 
57 

Table 18. Requirements and operational needs for ADS-equipped vehicles slowing down 

and increasing gap when passing over wet pavement. 

Functional 

Requirement 

Identifier Functional Requirement

Applicable to 

CARMA

RWM-R1.01 An ADS-equipped vehicle with at least Cooperation Class A capabilities shall 

provide for the ability to avoid crashes with other vehicles (vehicles with or 

without cooperation class capabilities) prior to, during, and after completion of 

the maneuver. Vehicle adjusts speed and prepares for other adjustments at 

beginning of weather-event zone. Communications shall be possible 

approximately every 1⁄10 s.

Yes, 

Cooperation

Class B and 

higher

BT-R1.02 See table 6 for the same requirement FR ID number. Yes, 

Cooperation

Class B and 

higher

BT-R1.03 See table 6 for the same requirement FR ID number. Yes, 

Cooperation

Class B and 

higher. 

BT-R1.04 See table 6 for the same requirement FR ID number. Yes, 

Cooperation

Class B and 

higher

RWM-R1.02 An ADS-equipped vehicle with at least Cooperation Class A capabilities shall 

be able to broadcast the windshield-wiper activation and/or ABS-engagement 

activation to other ADS-equipped vehicles with at least Cooperation Class A

within its short-range communications approximately every 1 s. 

Yes, 

Cooperation

Class B and 

higher

RWM-R1.03 An ADS-equipped vehicle with onboard weather-detection equipment and with 

at least Cooperation Class A capabilities shall be able to broadcast the detected 

weather data to other ADS-equipped vehicles with at least Cooperation 

Class A capabilities within its short-range communications approximately 

every 1 s.

Optional, 

Cooperation

Class B and 

higher

RWM-R1.04 An ADS-equipped vehicle with onboard weather-detection equipment shall be 

able to broadcast at a minimum the following weather-related data (if the 

related sensors are mounted onboard and are functioning properly):

• Wet-pavement indication. 

• Icy-pavement indication. 

• Black ice on pavement indication. 

• Weather sensor operational status (failed/operational). 

Optional, 

Cooperation

Class B and 

higher

RWM-R1.05 An ADS-equipped vehicle with at least Cooperation Class A capabilities shall 

be able to receive, decode, process, analyze, and react to the weather data from 

weather-detection vehicles equipped with ADS with at least Cooperation 

Class A capabilities within its short-range communications approximately 

every 1 s. 

Yes, 

Cooperation

Class B and 

higher

RWM-R1.06 A TMS shall be able to broadcast the detected weather data from its connected 

RWIS to ADS-equipped vehicles with at least Cooperation Class A capabilities 

within its short-range communications approximately every 5 s.

Yes, 

Cooperation

Class B and 

higher
58 

Functional 

Requirement 

Identifier Functional Requirement

Applicable to 

CARMA

RWM-R1.07 A TMS shall be able to broadcast, at a minimum, the following weather-related 

data (assuming the applicable sensor data are available):

• Pavement-surface condition indication. 

• Precipitation-presence indication. 

• Icing-conditions indication. 

• Location indication. 

• Weather sensor operational status (failed/operational). 

Yes

RWM-R1.08 An ADS-equipped vehicle with at least Cooperation Class A capabilities shall 

be able to receive, decode, process, analyze, and react to the weather data from 

a TMS via short-range communications approximately every 10 s.

Yes, 

Cooperation

Class B and 

higher

RWM-R1.09 An ADS-equipped vehicle with at least Cooperation Class A capabilities shall 

be able to broadcast the windshield-wiper activation and/or ABS-engagement 

activation in near real-time to other ADS-equipped vehicles with at least 

Cooperation Class A within its long-range communications approximately 

every 1 s. 

Optional, 

Cooperation

Class B and 

higher

RWM-R1.10 An ADS-equipped vehicle with onboard weather-detection equipment and at 

least Cooperation Class A capabilities shall be able to broadcast the detected 

weather data in near real-time to other ADS-equipped vehicles with at least 

Cooperation Class A capabilities within its long-range communications range 

approximately every 1 s. 

Optional, 

Cooperation

Class B and 

higher

RWM-R1.11 An ADS-equipped vehicle with onboard weather-detection equipment shall be 

able to broadcast at a minimum the following weather-related data (assuming 

the applicable sensor data are available):

• Pavement-surface condition indication. 

• Precipitation-presence indication

• Icing-conditions indication. 

• Location indication. 

• Weather-sensor operational status (failed/operational). 

Yes

RWM-R1.12 An ADS-equipped vehicle with at least Cooperation Class B capabilities shall 

be able to receive, decode, process, analyze, and react to the weather data from 

weather-detection vehicles equipped with ADS with at least Cooperation 

Class B capabilities within its long-range communications approximately 

every 1 s. 

Optional

RWM-R1.13 A TMS shall be able to broadcast the detected weather data to ADS-equipped

vehicles with at least Cooperation Class A capabilities within its long-range 

communications approximately every 10 s. 

Optional, 

Cooperation

Class B and 

higher

RWM-R1.14 A TMS shall be able to broadcast at a minimum the following weather-related 

data (if the related sensor data are available):

• Pavement-surface condition indication. 

• Precipitation-presence indication. 

• Icing-conditions indication. 

• Location indication. 

• Weather-sensor operational status (failed/operational). 

Yes

RWM-R1.15 An ADS-equipped vehicle with at least Cooperation Class B capabilities shall 

be able to receive, decode, process, analyze, and react to weather data from a 

TMS via long-range communications approximately every 10 s.

Optional

RWM-R1.16 An ADS-equipped vehicle with at least Cooperation Class A capabilities shall 

be able to broadcast its driving path for the previous 1 min of travel 

approximately every 1 s.

No
59 

Functional 

Requirement 

Identifier Functional Requirement

Applicable to 

CARMA

TIM-R1.12 See table 12 for the same requirement FR ID number. Yes

RWM-R1.17 An ADS-equipped vehicle with at least Cooperation Class B capabilities shall 

be able to interpret received intentions to reduce speeds due to weather events 

and process these intentions in conjunction with the locations, speeds, 

headings, and brake status received from other ADS-equipped vehicles with 

Cooperation Class A or higher. 

Yes

RWM-R1.18 An ADS-equipped vehicle shall be able to detect a vehicle not equipped with 

ADS if in detection range.

No

RWM-R1.19 An ADS-equipped vehicle shall have a means to visually display to the driver 

the location of other vehicles about which it has information.

Optional

RWM-R1.20 A TMS shall be able to continuously broadcast the detected RWIS weather 

data, including any modifications to the geofenced adverse-weather area 

approximately every 10 s. 

Yes, 

Cooperation

Class B and 

higher

RWM-R1.21 An ADS-equipped vehicle with at least Cooperation Class A capabilities shall 

be able to receive, decode, process, analyze, and use adverse-weather data 

from a TMS to determine when and where it can safely and efficiently resume 

its previous travel speeds.

Yes, 

Cooperation 

Class B and 

higher

RWM-R1.22 An ADS-equipped vehicle with at least Cooperation Class A capabilities shall 

be able to receive, decode, process, analyze, and use the adverse-weather data 

from an ADS-equipped vehicle with weather-detection equipment to determine 

when and where it can safely and efficiently resume its previous travel speeds.

Yes, 

Cooperation

Class B and 

higher

BT-R1.17 See table 6 for the same requirement FR ID number. Yes

RWM-R1.23 A TMS shall be able to receive vehicle operations and weather-related data 

(e.g., locations, speeds, headings, brake status, and available weather data) 

from an ADS-equipped vehicle with at least Cooperation Class A capabilities 

in a specified area that can provide weather data. Communications shall be 

possible approximately every 1 s via short- or long-range communications 

infrastructure to the TMS.

Yes

FR ID = functional requirement identification.

Performance Metrics

Key performance metrics for monitoring and evaluating operations during execution of 

situation 3, some of which were adapted from A Framework for Automated Driving System 

Testable Cases and Scenarios, should include the following: 

• Separation distances—longitudinal distances between the vehicles in the test. Separation 

distances are used to determine safe distances and the frequency of infringement of those 

distances (Thorn et al. 2018). 

• Disengagements—occurrence frequency when safety drivers deactivate the ADS feature 

being tested and take manual control of the vehicles (Thorn et al. 2018). 

• Travel speeds driven: Speeds driven by each of the vehicles during the tests will be used 

to create an accurate picture (playback) for evaluating driving within the vehicle travel 

areas.

• Deceleration rate—vehicle’s change-of-speed rate when approaching the wet pavement 

(Thorn et al. 2018). 
60 

• Weather-content message latency—the time difference between origination of the 

weather-content message from the TMS to receipt by the vehicle, including time to 

decompose and read the message.

• Speed changes—changes in speeds of the vehicles greater than (or less than) a specified 

threshold in response to interactions between ADS-equipped vehicles driving toward the 

adverse-weather area and an ADS-equipped maintenance vehicle (reduction in speeds by 

the vehicles reacting to weather information received from the equipped maintenance 

vehicle).

Requirements Traceability Matrix for Road Weather Management Operational Needs and 

Functional Requirements

Table 19 traces the relationship between operational needs and functional requirements. 

Table 19. Requirements traceability matrix for ADS-equipped vehicles slowing down and 

increasing gap when passing over wet pavement. 

Operational 

Need

Identifier Operational Need

Functional 

Requirement

Identifier Functional Requirement

RWM-N1.01 Safely travel along a 

roadway impacted by 

adverse weather.

RWM-R1.01 An ADS-equipped vehicle with at least Cooperation 

Class A capabilities shall provide for the capability to 

avoid crashes with other vehicles with or without 

cooperation class capabilities prior to, during, and 

after completion of the maneuver, Vehicle adjusts 

speed and prepares for other adjustments at beginning 

of weather-event zone. Communications shall be 

possible approximately every 1⁄10 s.

RWM-N1.02 Gather, integrate, process, 

and disseminate road 

weather information.

RWM-R1.02 An ADS-equipped vehicle with at least Cooperation 

Class A capabilities shall be able to broadcast the 

windshield-wiper activation and/or ABS-engagement 

activation to other ADS-equipped vehicles with at 

least Cooperation Class A within its short-range 

communications approximately every 1 s. 

RWM-N1.02 Gather, integrate, process, 

and disseminate road 

weather information.

RWM-R1.03 An ADS-equipped vehicle with, onboard 

weather-detection equipment and at least Cooperation 

Class A capabilities shall be able to broadcast the 

detected weather data to other ADS-equipped

vehicles with at least Cooperation Class A within its 

short-range communications approximately every 1 s. 

RWM-N1.02 Gather, integrate, process, 

and disseminate road 

weather information. 

RWM-R1.04 An ADS-equipped vehicle with onboard 

weather-detection equipment shall be able to 

broadcast at a minimum the following weather-related 

data (if the related onboard sensors are functioning 

properly):

• Wet-pavement indication. 

• Icy pavement indication. 

• Black ice on pavement indication. 

• Weather sensor operational status 

(failed/operational). 
61 

Operational 

Need

Identifier Operational Need

Functional 

Requirement

Identifier Functional Requirement

RWM-N1.02 Gather, integrate, process, 

and disseminate road 

weather information. 

RWM-R1.05 An ADS-equipped vehicle with at least Cooperation 

Class A capabilities shall be able to receive, decode, 

process, analyze, and react to the weather data from 

ADS-equipped weather-detection vehicles with at 

least Cooperation Class A capabilities within its 

short-range communications approximately every 1 s. 

RWM-N1.03 Gather location and speed 

information from vehicles 

near the ADS-equipped 

vehicle.

BT-R1.02 An ADS-equipped vehicle with at least Cooperation 

Class A capabilities shall be able to broadcast its 

location, speed, heading, and brake status 

approximately every 1⁄10 s.

RWM-N1.03 Gather location and speed 

information from vehicles 

near the ADS-equipped 

vehicle.

BT-R1.03 An ADS-equipped vehicle with at least Cooperation 

Class A capabilities shall be able to receive, decode, 

process, analyze, and use locations, speeds, and 

headings from other ADS-equipped vehicles with at 

least Cooperation Class A within its short-range 

communications range approximately every 1⁄10 s.

RWM-N1.03 Gather location and speed 

information from vehicles 

near the ADS-equipped 

vehicle.

RWM-R1.16 An ADS-equipped vehicle with at least Cooperation 

Class A capabilities shall be able to broadcast its 

driving path for the previous 1 min at approximately 

every 1 s.

RWM-N1.04 Accept and process road 

weather information 

(e.g., weather data, 

reduced speed limits, and 

recommended headways) 

to adjust speed and 

headway spacing 

accordingly.

RWM-R1.05 An ADS-equipped vehicle with at least Cooperation 

Class A capabilities shall be able to receive, decode, 

process, analyze, and react to the weather data from 

ADS-equipped weather-detection vehicles with at 

least Cooperation Class A capabilities within its 

short-range communications approximately every 1 s. 

RWM-N1.04 Accept and process road 

weather information 

(e.g., weather data, 

reduced speed limits, and 

recommended headways) 

to adjust speed and 

headway spacing 

accordingly. 

RWM-R1.08 An ADS-equipped vehicle with at least Cooperation 

Class A capabilities shall be able to receive, decode, 

process, analyze, and react to the weather data from a 

TMS via short-range communications approximately 

every 10 s.

RWM-N1.04 Accept and process road 

weather information 

(e.g., weather data, 

reduced speed limits, and 

recommended headways) 

to adjust speed and 

headway spacing 

accordingly. 

RWM-R1.12 An ADS-equipped vehicle with at least ADS vehicle 

with at least Cooperation Class B capabilities shall be 

able to receive, decode, process, analyze, and react to 

the weather data from ADS-equipped

weather-detection vehicles with at least Cooperation 

Class B capabilities within its long-range 

communications approximately every 1 s. 

RWM-N1.04 Accept and process road 

weather information 

(e.g., weather data, 

reduced speed limits, and 

recommended headways) 

to adjust speed and 

headway spacing 

accordingly. 

RWM-R1.15 An ADS-equipped vehicle with at least Cooperation 

Class B capabilities shall be able to receive, decode, 

process, analyze, and react to the weather data from a 

TMS via long-range communications approximately 

every 10 s.
62 

Operational 

Need

Identifier Operational Need

Functional 

Requirement

Identifier Functional Requirement

RWM-N1.04 Accept and process road 

weather information 

(weather data, reduced 

speed limits, and 

recommended headways) 

to adjust speed and 

headway spacing 

accordingly. 

RWM-R1.17 An ADS-equipped vehicle with at least Cooperation 

Class B capabilities shall be able to interpret received 

intentions to reduce speeds due to weather events and 

process these intentions in conjunction with the 

locations, speeds, headings, and brake status received 

from other ADS-equipped vehicles with Cooperation 

Class A capabilities or higher. 

RWM-N1.04 Accept and process road 

weather information 

(weather data, reduced 

speed limits, and 

recommended headways) 

to adjust speed and 

headway spacing 

accordingly. 

RWM-R1.21 An ADS-equipped vehicle with at least Cooperation 

Class A capabilities shall be able to receive, decode, 

process, analyze, and use the adverse-weather data 

from a TMS to determine when and where it can 

safely and efficiently resume its previous travel 

speeds.

RWM-N1.04 Accept and process road 

weather information 

(weather data, reduced 

speed limits, and 

recommended headways) 

to adjust speed and 

headway spacing 

accordingly. 

RWM-R1.22 An ADS-equipped vehicle with at least Cooperation 

Class A capabilities shall be able to receive, decode, 

process, analyze, and use the adverse-weather data 

from an ADS- and weather detection-equipped 

vehicle to determine when and where it can safely and 

efficiently resume its previous travel speeds.

RWM-N1.05 Transmit road weather 

information to other 

vehicles.

RWM-R1.02 An ADS-equipped vehicle with at least Cooperation 

Class A capabilities shall be able to broadcast the 

windshield-wiper activation and/or ABS-engagement 

activation to other ADS-equipped vehicles with at 

least Cooperation Class A capabilities within its 

short-range communications approximately every 1 s. 

RWM-N1.05 Transmit road weather 

information to other 

vehicles.

RWM-R1.03 An ADS-equipped vehicle with onboard 

weather-detection equipment and with at least 

Cooperation Class A capabilities shall be able to 

broadcast the detected weather data to other 

ADS-equipped vehicles with at least Cooperation 

Class A capabilities within its short-range 

communications range every 1 s. 

RWM-N1.05 Transmit road weather 

information to other 

vehicles.

RWM-R1.04 An ADS-equipped vehicle with onboard 

weather-detection equipment shall be able to 

broadcast at a minimum the following weather-related 

data (if the onboard sensors are mounted and 

functioning properly):

• Wet-pavement indication. 

• Icy pavement indication. 

• Black ice on pavement indication. 

• Weather sensor operational status 

(failed/operational). 

RWM-N1.05 Transmit road weather 

information to other 

vehicles.

RWM-R1.06 A TMS shall be able to broadcast the detected 

weather data from its connected RWIS to 

ADS-equipped vehicles with at least Cooperation 

Class A capabilities within its short-range 

communications approximately every 5 s.
63 

Operational 

Need

Identifier Operational Need

Functional 

Requirement

Identifier Functional Requirement

RWM-N1.05 Transmit road weather 

information to other 

vehicles.

RWM-R1.07 A TMS shall be able to broadcast, at a minimum, the 

following weather-related data (assuming the 

applicable sensor data are available):

• Pavement surface condition indication. 

• Precipitation presence indication. 

• Icy conditions indication. 

• Location indication. 

• Weather sensor operational status 

(failed/operational). 

RWM-N1.05 Transmit road weather 

information to other 

vehicles.

RWM-R1.09 An ADS-equipped vehicle with at least Cooperation 

Class A capabilities shall be able to broadcast the 

windshield-wiper activation and/or ABS-engagement 

activation in near real-time to other ADS-equipped

vehicles with at least Cooperation Class A capabilities 

within its long-range communications approximately 

every 1 s. 

RWM-N1.05 Transmit road weather 

information to other 

vehicles.

RWM-R1.10 An ADS-equipped vehicle with onboard 

weather-detection equipment and at least Cooperation 

Class A capabilities shall be able to broadcast the 

detected weather data in near real-time to other 

ADS-equipped vehicles with at least Cooperation 

Class A capabilities within its long-range 

communications approximately every 1 s. 

RWM-N1.05 Transmit road weather 

information to other 

vehicles. 

RWM-R1.11 An ADS-equipped vehicle with onboard 

weather-detection equipment shall be able to 

broadcast at a minimum the following weather-related 

data (assuming the applicable sensor data are 

available):

• Pavement-surface condition indication. 

• Precipitation presence indication. 

• Icy conditions indication. 

• Location indication. 

• Weather-sensor operational status 

(failed/operational). 

RWM-N1.05 Transmit road weather 

information to other 

vehicles.

RWM-R1.13 A TMS shall be able to broadcast detected weather 

data to ADS-equipped vehicles with at least 

Cooperation Class A capabilities within its long-range 

communications approximately every 10 s.

RWM-N1.05 Transmit road weather 

information to other 

vehicles.

RWM-R1.14 A TMS shall be able to broadcast at a minimum the 

following weather-related data (if the related sensor 

data are available):

• Pavement-surface condition indication. 

• Precipitation presence indication. 

• Icy conditions indication. 

• Location indication. 

• Weather-sensor operational status 

(failed/operational). 

RWM-N1.06 Detect vehicles incapable 

of cooperating with other 

vehicles.

RWM-R1.18 An ADS-equipped vehicle shall be able to detect the 

reduction of speed in a vehicle without ADS if it is in 

detection range.
64 

Operational 

Need

Identifier Operational Need

Functional 

Requirement

Identifier Functional Requirement

RWM-N1.06 Detect vehicles incapable 

of cooperating with other 

vehicles.

RWM-R1.19 An ADS-equipped vehicle shall have a means to 

visually display to the driver the location of other 

vehicles about which it has information.

RWM-N1.07 Visual alerts about 

adverse-weather 

conditions from ITS 

devices or radio 

broadcasts.

RWM-R1.02 An ADS-equipped vehicle with at least Cooperation 

Class A capabilities shall be able to broadcast the 

windshield-wiper activation and/or ABS-engagement 

activation to other ADS-equipped vehicles with at 

least Cooperation Class A capabilities within its 

short-range communications approximately every 1 s. 

RWM-N1.07 Visual alerts about 

adverse-weather 

conditions from ITS 

devices or radio 

broadcasts.

RWM-R1.04 An ADS-equipped vehicle with onboard 

weather-detection equipment shall be able to 

broadcast at a minimum the following weather-related 

data (if the onboard sensors are mounted and 

functioning properly):

• Wet-pavement indication. 

• Icy-pavement indication. 

• Black ice on pavement indication. 

• Weather sensor operational status 

(failed/operational). 

RWM-N1.07 Visual alerts about 

adverse-weather 

conditions from ITS 

devices or radio 

broadcasts.

RWM-R1.07 A TMS shall be able to broadcast, at a minimum, the 

following weather-related data (assuming the 

applicable sensors data are available):

• Pavement-surface condition indication

• Precipitation presence indication. 

• Icy conditions indication. 

• Location indication. 

• Weather sensor operational status 

(failed/operational). 

RWM-N1.07 Visual alerts about 

adverse-weather 

conditions from ITS 

devices or radio 

broadcasts.

RWM-R1.09 An ADS-equipped vehicle with at least Cooperation 

Class A capabilities shall be able to broadcast the 

windshield-wiper activation and/or ABS-engagement 

activation in near real-time to other ADS-equipped

vehicles with at least Cooperation Class A capabilities 

within its long-range communications approximately 

every 1 s. 

RWM-N1.07 Visual alerts about 

adverse-weather 

conditions from ITS 

devices or radio 

broadcasts.

RWM-R1.11 An ADS-equipped vehicle with onboard 

weather-detection equipment shall be able to 

broadcast at a minimum the following weather-related 

data (assuming the applicable sensor data are 

available):

• Pavement-surface condition indication. 

• Precipitation-presence indication. 

• Icing-conditions indication. 

• Location indication. 

• Weather sensor operational status 

(failed/operational). 
65 

Operational 

Need

Identifier Operational Need

Functional 

Requirement

Identifier Functional Requirement

RWM-N1.07 Visual alerts about 

adverse-weather 

conditions from ITS 

devices or radio 

broadcasts.

RWM-R1.14 A TMS shall be able to broadcast at a minimum the 

following weather-related data (if the related sensor 

data are available):

• Pavement-surface condition indication.

• Precipitation-presence indication.

• Icing-conditions indication.

• Location indication.

• Weather sensor operational status 

(failed/operational).

RWM-N1.08 Need information on 

acceptable speed limits to 

safely navigate roadways 

affected by 

adverse-weather 

conditions.

RWM-R1.17 An ADS-equipped vehicle with at least Cooperation 

Class B capabilities shall be able to interpret received 

intentions to reduce speeds due to weather events and 

process these intentions in conjunction with the 

locations, speeds, headings, and brake status received 

from other ADS-equipped vehicles with Cooperation 

Class A capabilities or higher. 

RWM-N1.08 Information on acceptable 

speed limits to safely 

navigate roadways 

affected by 

adverse-weather 

conditions.

RWM-R1.18 An ADS-equipped vehicle shall be able to detect a 

reduction in speed of a vehicle not equipped with 

ADS if it is in detection range.

RWM-N1.08 Information on acceptable 

speed limits to safely 

navigate roadways 

affected by 

adverse-weather 

conditions.

RWM-R1.21 An ADS-equipped vehicle with at least Cooperation 

Class A capabilities shall be able to receive, decode, 

process, analyze, and use the adverse-weather data 

from a TMS to determine when and where it can 

safely and efficiently resume its previous travel 

speeds. 

RWM-N1.08 Information on acceptable 

speed limits to safely 

navigate roadways 

affected by 

adverse-weather 

conditions.

RWM-R1.22 An ADS-equipped vehicle with at least Cooperation 

Class A capabilities shall be able to receive, decode, 

process, analyze, and use the adverse-weather data 

from an ADS-equipped vehicle with weatherdetection equipment to determine when and where it 

can safely and efficiently resume its previous travel 

speeds.

RWM-N1.09 Capability to determine 

pavement temperature and 

presence of water, snow, 

or ice on the roadway.

RWM-R1.04 An ADS-equipped vehicle with onboard weather 

detection equipment shall be able to broadcast at a 

minimum the following weather-related data (if the 

related sensors are onboard and are functioning 

properly):

• Wet-pavement indication. 

• Icy-pavement indication. 

• Black ice on pavement indication. 

• Weather sensor operational status 

(failed/operational). 
66 

Operational 

Need

Identifier Operational Need

Functional 

Requirement

Identifier Functional Requirement

RWM-N1.09 Capability to determine 

pavement temperature and 

presence of water, snow, 

or ice on the roadway. 

RWM-R1.07 A TMS shall be able to broadcast at a minimum the 

following weather-related data (assuming the 

applicable sensors data are available):

• Pavement-surface condition indication. 

• Precipitation-presence indication. 

• Icing-conditions indication. 

• Location indication. 

• Weather-sensor operational status 

(failed/operational). 

RWM-N1.09 Capability to determine 

pavement temperature and 

presence of water, snow, 

or ice on the roadway. 

RWM-R1.11 An ADS-equipped vehicle with onboard 

weather-detection equipment shall be able to 

broadcast at a minimum the following weather-related 

data (assuming the applicable sensor data are 

available):

• Pavement-surface condition indication.

• Precipitation-presence indication.

• Icing-conditions indication.

• Location indication.

• Weather-sensor operational status 

(failed/operational).

RWM-N1.09 Capability to determine 

pavement temperature and 

presence of water, snow, 

or ice on the roadway. 

RWM-R1.14 A TMS shall be able to broadcast at a minimum the 

following weather-related data (if the related sensor 

data are available):

• Pavement-surface condition indication.

• Precipitation-presence indication.

• Icing-conditions indication.

• Location indication.

• Weather-sensor operational status 

(failed/operational).

RWM-N1.10 Provide road weather 

condition information to 

ADS-equipped vehicles in 

a geofenced area.

RWM-R1.20 A TMS shall be able to continuously broadcast the 

detected RWIS weather data, including any 

modifications to the geofenced adverse-weather area 

approximately every 10 s. 

RWM-N1.11 Provide road weather 

condition response 

suggestions (reduced 

speed limits and 

recommended headways) 

to ADS-equipped vehicles 

in a geofenced area.

RWM-R1.21 An ADS-equipped vehicle with at least Cooperation 

Class A capabilities shall be able to receive, decode, 

process, analyze, and use the adverse-weather data 

from a TMS and use that information to determine 

when and where it can safely and efficiently resume 

its previous travel speeds.

RWM-N1.11 Provide road weather 

condition response 

suggestions (reduced 

speed limits and 

recommended headways) 

to ADS-equipped vehicles 

in a geofenced area.

RWM-R1.22 An ADS-equipped vehicle with at least Cooperation 

Class A capabilities shall be able to receive, decode, 

process, analyze, and use the adverse-weather data 

from an ADS-equipped vehicle with weatherdetection equipment to determine when and where it 

can safely and efficiently resume its previous travel 

speeds.

RWM-N1.12 Gather and process data 

from ITS devices and 

ADS-equipped vehicles to 

monitor current traffic 

conditions.

RWM-R1.16 An ADS-equipped vehicle with at least Cooperation 

Class A capabilities shall be able to broadcast its 

driving path for the previous 1 min approximately 

every 1 s. 
67 

Operational 

Need

Identifier Operational Need

Functional 

Requirement

Identifier Functional Requirement

RWM-N1.12 Gather and process data 

from ITS devices and 

ADS-equipped vehicles to 

monitor current traffic 

conditions.

RWM-R1.23 A TMS shall be able to receive vehicle operations and 

weather-related data (e.g., locations, speeds, headings, 

brake status, and available weather data) from an 

ADS-equipped vehicle with at least Cooperation 

Class A capabilities in a specified area that can 

provide weather data. Communications shall be 

possible approximately every 1 s via short- or 

long-range communications infrastructure to the 

TMS.

69 

CHAPTER 6. USE CASE: WZM

PRIORITY SITUATION 4 TREATMENT: ADS-EQUIPPED VEHICLES NAVIGATING

A ONE-LANE, TWO-WAY TRAFFIC TAPER IN A WORK ZONE

The subject of this situational analysis is an ADS feature with a specified ODD that includes 

operation of ADS-equipped vehicles safely navigating a work zone on a roadway with one lane 

in each direction with one lane blocked because of a work zone. This will require the vehicle to 

temporarily merge into the lane going in the opposite direction to pass the work zone. The 

roadway is populated by vehicles of different Automation Levels and Cooperation Classes. 

ADS-equipped vehicles travel through the ADS vehicle travel areas of advanced 

warning/notification, transition, activity, and termination. These travel areas are defined in 

chapter 2. 

Situation 4 involves several vehicles positioned on a roadway with one lane in each direction. 

One lane is blocked because of a work zone and the presence of workers. The work-zone setup 

will follow MUTCD guidelines. Typically, the traffic control for similar situations can be 

performed by a flagger or a traffic light. In this situation, a traffic light with the ability to 

transmit signal phasing and timing (SPaT) data will be used, and the TMS provides digital layout 

of the work zone. ADS-equipped vehicles approaching the work zone will have to gradually 

slow down to the work-zone speed limit, detect the signal phase, cross over the double yellow 

centerline to merge into the lane going in the opposite direction if the signal is green (i.e., bottom 

indication is active), and change lanes again to go back to regular operations after passing the 

work zone. The vehicles traveling in the opposite direction will receive a red signal (i.e., top 

indication is active) and stop until the lane is cleared of oncoming traffic. 

The situational layout is depicted in figure 24. The situation includes vehicles with different 

cooperation class capabilities shown in red circles in the graphic. 

Source: FHWA.

Figure 24. Illustration. WZM situational layout. 

Operational Needs

This situation is intended to address specific operational user needs, detailed in table 20 through 

table 23. 
70 

Table 20. Operational needs for WZM. 

Operational 

Need 

Identifier Operational Need

WZM-N1.01 Safely approach, navigate through, and clear a work zone.

WZM-N1.02 Possess situational awareness regarding the work zone, including workers and TCDs. 

WZM-N1.03 Gather, integrate, process, and disseminate work-zone information.

Table 21. WZM—operational needs for ADS-equipped vehicles in a work zone. 

Operational 

Need 

Identifier Operational Needs for ADS-Equipped Vehicles 

WZM-N1.04 Receive and process SPaT and work-zone geographic layout (MAP) messages from traffic signals 

controlling the approaches to the work zone.

WZM-N1.05 Gather location and speed information from vehicles near ADS-equipped vehicles.

WZM-N1.06 Detect any workers or TCDs encroaching on the travel lane.

WZM-N1.07 Detect vehicles incapable of cooperating with other vehicles.

WZM-N1.08 Detect vehicles entering or exiting the work zone.

Table 22. WZM—operational needs for non-ADS equipped vehicles (human driver).

Operational 

Need 

Identifier Operational Need for Non-ADS (Human Driver)

WZM-N1.09 Visual alerts upstream and when navigating the work zone.

Table 23. WZM—operational needs for TMS. 

Operational 

Need 

Identifier Operational Need for Traffic Management Service

WZM-N1.10 Provide geofenced work-zone information, including speed limits, to ADS-equipped vehicles 

approaching the work zone. 

WZM-N1.11 Manage variable message signs and other traveler information systems to provide vehicles 

approaching the work zone with visual and/or audible information about the work zone.

WZM-N1.12 Gather and process data from ITS devices and ADS-equipped vehicles to monitor current traffic 

conditions.

Stakeholders and Entities

Researchers can execute the operational situation using several vehicles. The focus of CARMA 

is on Automation Level 3 or higher and Cooperation Class B or higher, but under real-world 

conditions, other vehicles will also be encountered that might be equipped with lower 

Automation Levels and Cooperation Classes. The following stakeholders and entities, and their 

associated minimum vehicle configurations, should be considered when executing this 

operational situation within CARMA:
71 

• Vehicle 1 navigating the controlled one-way work zone-related, one-lane, two-way traffic 

taper:

o ADS vehicle with Automation Level 3 and Cooperation Class B. 

• Vehicle 2 (in front of the first vehicle arriving at the work zone-related, one-lane, 

two-way traffic taper):

o ADS vehicle with Automation Level 3 and Cooperation Class B. 

• Vehicle 3 (behind the first vehicle arriving at the work zone-related, one-lane, two-way 

traffic taper):

o ADS vehicle with Automation Level 3 and Cooperation Class B. 

Traffic lights, flaggers, or broadcasting work-zone channeling devices (i.e., cones) at each end of 

the work zone can be used to manage the one-way traffic through the work zone. 

Another stakeholder is a TMS operator (or software package) that will monitor the positions of 

each vehicle for recording and storage purposes. While many smaller, one-way traffic taper work 

zones are managed locally without control or monitoring by a TMS, a TMS could also control 

and manage a traffic signal or configure a broadcasting work-zone channeling device. If an RSU 

is used for the communications, then the TMS would need to monitor the communications 

associated with the RSU.

User-Oriented Operational Description

Concept Diagram 

Priority Situation 4 includes several ADS vehicle travel areas—advanced warning/notification, 

transition, activity, and termination—that are explained in the following sections. The concepts 

include an overview diagram for each ADS-equipped vehicle travel area, a description, and a 

table that shows how vehicles with different Automation Levels and Cooperation Classes would 

react and respond within each travel area of the one-lane, two-way traffic taper WZM situation.

For the following descriptions of ADS vehicle travel areas to be used within CARMA, all vehicles 

support at least Cooperation Class B capabilities. 

Advanced Warning/Notification Vehicle Travel Area

Within the advanced warning/notification vehicle travel area, ADS-equipped vehicles travel 

along a one-lane roadway when they all receive a TMS broadcast with a notification of a 

downstream work zone that closes the lane in which the vehicles are traveling and they will have 

to obey a traffic signal prior to the work zone. Alternatively, the vehicles could exit to take a 

detour, as shown in figure 25. 
72 

Source: FHWA.

Figure 25. Illustration. WZM-ADS-equipped vehicles receiving a notification. 

The information from the TMS includes location of the work zone (start and end locations), start 

and end work times in the work zone, queue information prior to the work zone (if any), and 

alternative route suggestions (if any). The TMS also takes advantage of a VMS located just 

before the nearest exit and prior to the work zone by posting a message to warn vehicles of the 

work zone and the availability of a detour. 

The first vehicles downstream of the vehicles under test (those with circles) have arrived and are 

stopped in front of a traffic light regulating the traffic around the work zone, which currently 

shows a red light (top indication is active). The upstream vehicles receive the traffic-signal status 

information as well as the work-zone layout via a map data (MAP) message. The upstream 

vehicles process the data to avoid any rear-end accidents and/or to minimize the deceleration 

and/or stop time at the signal.

The traffic light operates on a fixed-cycle basis and does not react to locally detected volumes or 

delays (this is the normal mode of operations, particularly in more rural areas and/or in 

conjunction with small, temporally limited work zones). The traffic light is assumed to be 

configured with a preprogrammed cycle length and green light splits that are managed locally 

(as opposed to being managed by a TMS with signal-control capabilities, which is an option 

often used in cities). However, the traffic light provides its light-status data (e.g., SPaT data, 

failure status) to the vehicles directly via short- or long-range communications. Furthermore, the 

TMS broadcasts the digital layout of the work zone (via MAP messages) to the vehicles, which 

includes work-zone start location (first channeling device) and date/time, channeling devices 

taper angle, work-zone end location (first channeling device where the taper ends) and taper-end 

angle, as well as other data, such as work-zone entry and exit locations (if applicable). 

Alternatively, instead of traffic lights managing the traffic around such a work zone, human or 

mechanical flaggers can be positioned at each end of the work zone to coordinate which 

direction is open for traffic as well as to ensure that the traffic already in the work zone has 

cleared. Another alternative or addition is the provision of smart channeling devices 

(e.g., intelligent cones with broadcasting capabilities), which could broadcast their locations as 

well as other information. 

Simultaneously, all vehicles involved in this situation are communicating with each other, 

exchanging data about their operational status (e.g., location, speed, and heading). Those 
73 

vehicles that follow the suggested detour would broadcast that fact via their location, speed, 

heading, and potential intention data; however, for this situation, no vehicle is assumed to follow 

a detour suggestion. 

Vehicle Travel Transition Area

Within the transition area, ADS-equipped vehicles are restarting or accelerating to the posted 

work-zone speed limit, which is lower than the normal speed limit and appropriate for the work 

zone, to pass the work zone after the traffic light has changed to green (bottom indication is 

active) as shown in figure 26. The traffic light is programmed to allow sufficient time for 

vehicles in the opposite direction to clear the work zone and not block the one lane available 

within the work zone for oncoming vehicles. The traffic light continues to broadcast its light 

status, including the change to green (bottom indication is active) for the direction from which 

the vehicles under test are coming. 

Source: FHWA. 

Figure 26. Illustration. WZM—vehicle transition area. 

The ADS-equipped vehicles, which are programmed not to cross a double yellow centerline, are 

crossing the double yellow centerline to pass the work zone in the one available lane. This 

maneuver will only take place when the light is green (bottom indication is active) and the 

downstream vehicles have moved. The ADS-equipped vehicles broadcast their locations, speeds, 

headings, and path intentions. ADS-equipped vehicles with Cooperation Class C capabilities 

exchange data with each other to coordinate the moving maneuvers each vehicle is executing. 

ADS-equipped vehicles arriving late in the green cycle (bottom indication is active) at the traffic 

light receive, process, analyze, and use SPaT and MAP data, as well as the location data from 

other downstream vehicles, to determine whether they can pass the traffic light while still green

(bottom indication is active) or if they have to prepare to stop in front of the traffic light.

Vehicle Travel Activity Area

Within the activity area, ADS-equipped vehicles on the one-directional lane pass the work zone. 

They broadcast their current locations, as well as their intended-path information, to each other 

and any other listening device (e.g., TMS via short- or long-range communications media). Any 

unusual obstacles (e.g., a vehicle exiting from the actual protected work zone or a person 

working within the work zone) will be detected by the nearest upstream vehicle and reported to 

all other nearby vehicles and the TMS. 
74 

The traffic light in the direction of the ADS-equipped vehicles is still continuously broadcasting 

its status, including remaining green time (bottom indication is active) within a geofenced area 

around the work zone, which is received by ADS-equipped vehicles, as shown in figure 27. 

Source: FHWA.

Figure 27. Illustration. WZM—vehicle activity area.

Vehicle Travel Termination Area

Within the termination area, ADS-equipped vehicles have reached the end of the contraflow 

one-lane work-zone area and are moving over into their original through lane, as shown in 

figure 28. 

Source: FHWA.

Figure 28. Illustration. WZM—termination area.

ADS-equipped vehicles with Cooperation Class C capabilities are exchanging data to negotiate 

the merging area between the work-zone end and the vehicles in the opposite direction waiting at 

their traffic light, which still shows a red light (top indication is active). 

Once the ADS-equipped vehicles have reached the through lane in their direction and passed the 

reduced speed limit area, they accelerate to the normal speed limit, while broadcasting their 

location, speed, and heading information to other vehicles in the vicinity. 

As soon as the work zone is resolved, the TMS removes the work-zone warning and 

alternate-route message from the upstream VMS.
75 

Trigger to Invoke Situation of ADS-Equipped Vehicles Navigating a One-Lane, Two-Way 

Traffic Taper in a Work Zone 

Priority situation 4 is triggered when ADS-equipped vehicles are first informed of the existence 

of the work zone upstream either by the TMS or a local method, which is broadcasting data of 

the downstream work zone. Additionally, vehicles are informed via an upstream VMS where the 

TMS posted the warning message. The following indicators are designated as triggers to invoke 

responses of ADS-equipped vehicles: 

• Broadcast from the TMS.

• Broadcast from a local device as part of the work-zone setup. 

• Reading/comprehending a corresponding message posted on a VMS (optical character 

recognition technology). 

Additional triggers are needed and will be used when ADS-equipped vehicles approach the work 

zone in response to the traffic light (or flagger or broadcasting channeling device) and to cross 

the otherwise noncrossable double yellow line.

Requirements

The requirements to address the situation and to fulfill the stated user-operational needs are 

defined in table 24. 

Table 24. Requirements for ADS-equipped vehicles navigating a one-lane, two-way traffic 

taper in a work zone.

Functional 

Requirement

Identifier Functional Requirement

Applicable to 

CARMA

BT-R1.01 See table 6 for the same requirement FR ID number. Yes, 

Cooperation

Class B and 

higher

BT-R1.02 See table 6 for the same requirement FR ID number. Yes, 

Cooperation

Class B and 

higher

BT-R1.03 See table 6 for the same requirement FR ID number. Yes, 

Cooperation

Class B and 

higher

BT-R1.04 See table 6 for the same requirement FR ID number. Yes, 

Cooperation

Class B and 

higher

WZM-R1.01 An ADS-equipped vehicle with at least Cooperation Class A capabilities

shall be able to receive, decode, process, analyze, and use work-zone data 

(start and end location, lanes affected, date/time of work-zone activities, 

associated speed limits prior to and within the work zone) obtained from the 

TMS via short-range communications approximately every 1 s. 

Yes, 

Cooperation

Class B and 

higher
76 

Functional 

Requirement

Identifier Functional Requirement

Applicable to 

CARMA

WZM-R1.02 An ADS-equipped vehicle with at least Cooperation Class A capabilities 

shall be able to receive, decode, process, analyze, and use data about the 

work-zone geographic layout obtained from the TMS via short-range 

communications approximately every 1 s. 

Yes, 

Cooperation

Class B and 

higher

WZM-R1.03 An ADS-equipped vehicle with at least Cooperation Class A capabilities 

shall be able to receive, decode, process, analyze, and use traffic-signal status 

data from the traffic light via short-range communications approximately 

every 1⁄10 s.

Yes, 

Cooperation

Class B and 

higher

BT-R1.05 See table 6 for the same requirement FR ID number. Optional, 

Cooperation

Class B and 

higher

BT-R1.06 See table 6 for the same requirement FR ID number. Optional, 

Cooperation

Class B and 

higher

WZM-R1.04 An ADS-equipped vehicle with at least Cooperation Class B capabilities shall 

be able to receive, decode, process, analyze, and use work-zone data (start 

and end location, lanes affected, date/time of work-zone activities, associated 

speed limits prior to and within the work zone) obtained from the TMS via 

long-range communications approximately every 1 s. 

Optional

WZM-R1.05 An ADS-equipped vehicle with at least Cooperation Class B capabilities shall 

be able to receive, decode, process, analyze, and use data about the 

work-zone geographic layout obtained from the TMS via long-range 

communications approximately every 1 s. 

Optional

WZM-R1.06 An ADS-equipped vehicle with at least Cooperation Class B capabilities shall 

be able to receive, decode, process, analyze, and use traffic-signal status data 

from the traffic light via long-range communications approximately every 1⁄10

s. 

Optional

WZM-R1.07 An ADS-equipped vehicle shall be able to detect, decode, process, analyze, 

and react to the work-zone message posted on a VMS prior to the work zone 

using visual detection onboard sensors and optical code recognition 

technology.

No

WZM-R1.08 An ADS-equipped vehicle with at least Cooperation Class A capabilities 

shall be able to broadcast its driving path for the previous 1 min

approximately every 1 s. 

No

WZM-R1.09 An ADS-equipped vehicle with at least Cooperation Class B capabilities shall 

be able to broadcast its intended future driving path for at least the next 15 s 

approximately every 3 s.

Yes, 

Cooperation

Class B and 

higher

WZM-R1.10 An ADS-equipped vehicle shall be able to interpret the presence of a tapered 

barrier (in the form of channeling devices) in conjunction with a traffic light 

showing green to allow it to cross a double yellow line and proceed in the 

opposing driving lane to pass the work-zone area (before moving into the 

opposite direction lane).

Yes

WZM-R1.11 An ADS-equipped vehicle shall be able to detect any oncoming vehicles still 

present in the opposing lane before moving into the opposite direction lane.

Yes

WZM-R1.12 An ADS-equipped vehicle shall not drive into the opposing lane if any 

oncoming vehicles have been detected (and instead stop in its own lane until 

all oncoming vehicles have passed).

Yes

WZM-R1.13 An ADS-equipped vehicle shall be able to detect and either slow down or 

stop when a work-zone vehicle exits the work zone.

Yes
77 

Functional 

Requirement

Identifier Functional Requirement

Applicable to 

CARMA

WZM-R1.14 An ADS-equipped vehicle shall be able to detect and either slow down or 

stop when a worker in the work zone steps into the lane in front of the 

ADS-equipped vehicle.

Optional

WZM-R1.15 An ADS-equipped vehicle with Cooperation Class C capabilities shall be 

able to send and receive, decode, process, analyze, and use detailed intention 

data, including ACKs and NAKs when cooperating with other ADS-equipped

vehicles with Cooperation Class C capabilities during the work-zone bypass 

maneuver, including interactions with work-zone vehicles coming out of or 

driving into the work zone.

Yes

WZM-R1.16 An ADS-equipped vehicle shall be able to use onboard sensors to detect the 

location, speed, and heading at suitable sensing intervals of 

non-ADS-equipped vehicles with no cooperation capabilities within its 

vicinity.

Yes

BT-R1.16 See table 6 for the same requirement FR ID number. Optional

WZM-R1.17 An ADS-equipped vehicle shall be able to detect, decode, process, analyze, 

and use the end-of-work-zone area and merge into the original lane in a safe 

and efficient manner.

Yes

WZM-R1.18 An ADS-equipped vehicle shall use the end-of-work-zone area information to 

determine how it can safely and efficiently resume its previous travel speed.

Yes

BT-R1.17 See table 6 for the same requirement FR ID number. Yes

WZM-R1.19 A TMS shall be able to broadcast a work-zone notification message to a 

geofenced area around the work zone. Communications shall be possible 

approximately every 1 s via short- or long-range communications 

infrastructure to the TMS.

Yes

WZM-R1.20 A TMS shall be able to broadcast the geographic layout of the work zone to a 

geofenced area around the work zone. Communications shall be possible 

approximately every 1 s via short- or long-range communications 

infrastructure to the TMS.

Yes

WZM-R1.21 A TMS shall be able to post a message on VMS prior to the work zone. Yes

WZM-R1.22 A TMS shall be able to modify a message posted on VMS prior to the work 

zone.

Yes

WZM-R1.23 A TMS shall be able to delete a message posted on VMS prior to the work 

zone and display the previously displayed message (if applicable). 

Yes

WZM-R1.24 A traffic-light system installed prior to the work zone shall be able to 

broadcast its traffic-light status, including the green-light status 

approximately every 1⁄10 s via short-range communications.

Yes

WZM-R1.25 A traffic-light system installed prior to the work zone shall be able to 

broadcast its traffic-light status, including the green-light status 

approximately every 1⁄10 s via long-range communications.

Optional

ACK = acknowledgment; FR ID = functional requirement identification.

Performance Metrics

Key performance metrics for monitoring and evaluating operations during execution of this 

situation, some of which were adapted from A Framework for Automated Driving System 

Testable Cases and Scenarios, should include the following: 

• Separation distances—longitudinal distances between the vehicles in the test. Separation 

distances are used to determine safe distances and the frequency of infringement of those 

distances (Thorn et al. 2018). 
78 

• Disengagements—occurrence frequency when safety drivers deactivate the ADS feature 

being tested and take manual control of the vehicles (Thorn et al. 2018). 

• Travel speeds driven—speeds driven by each of the vehicles during the tests will be used 

to create an accurate picture (playback) for evaluating driving within the vehicle travel 

areas.

• Deceleration rate—vehicle’s change-of-speed rate when approaching the work zone 

(Thorn et al. 2018). 

• SPaT message latency—the time difference between origination of the SPaT message 

from the controller to receipt by the vehicle, including time to decompose and read the 

message.

• MAP message latency—the time difference between origination of the MAP message 

from the TMS to receipt by the vehicle, including time to decompose and read the 

message.

• Data exchanges during negotiation (Cooperation Class C)—capture all data exchanges 

between two Cooperation Class C ADS-equipped vehicles, vehicle 1 and vehicle 2, to 

determine whether the maneuver negotiations occurred as designed. The data exchanges 

include the following data types: 

o Total duration of negotiation process. 

o Frequency of negotiation success/failure (NAKs from neighboring vehicles). 

o Number of attempts before a plan is accepted by all affected neighbors. 

o Message latency. 

Message latency refers to the time difference between message origination on vehicle 1 to 

reading of message by vehicle 2. The latency time includes the time to compose the message, 

sending the message from vehicle 1’s guidance computer to vehicle 1’s OBU, queuing time on 

vehicle 1’s OBU, radio transmission from vehicle 1 to vehicle 2, message constitution and

queueing on vehicle 2’s OBU, sending the message from vehicle 2’s OBU to vehicle 2’s 

guidance computer, and the time for vehicle 2 to decompose and read the message.

Requirements Traceability Matrix for WZM Operational Needs and Functional 

Requirements

Table 25 traces the relationship between operational needs and functional requirements. 
79 

Table 25. Requirements traceability matrix for ADS-equipped vehicles navigating a 

one-lane, two-way traffic taper in a work zone.

Operational 

Need 

Identifier Operational Need

Functional 

Requirement

Identifier Functional Requirement

WZM-N1.01 Safely approach, navigate 

through, and clear a work 

zone.

BT-R1.01 An ADS-equipped vehicle with at least 

Cooperation Class A capabilities shall provide for 

the ability to avoid crashes with other vehicles 

(vehicles with or without cooperation class 

capabilities) prior to, during, and after completion 

of the merging maneuver. Communications shall 

be possible approximately every 1⁄10 s. 

WZM-N1.02 Situational awareness 

regarding the work area 

including the workers and 

TCD.

BT-R1.02 An ADS-equipped vehicle with at least 

Cooperation Class A capabilities shall be able to 

broadcast its location, speed, heading, and brake 

status approximately every 1⁄10 s. 

WZM-N1.02 Situational awareness 

regarding the work area 

including the workers and 

TCD.

BT-R1.03 An ADS-equipped vehicle with at least 

Cooperation Class A capabilities shall be able to 

receive, decode, process, analyze, and use 

locations, speeds, and headings from other 

ADS-equipped vehicles with at least Cooperation 

Class A capabilities within its short-range 

communications approximately every 1⁄10 s.

WZM-N1.02 Situational awareness 

regarding the work area 

including the workers and 

TCD.

BT-R1.04 An ADS-equipped vehicle with at least 

Cooperation Class A capabilities shall be able to 

receive, decode, process, analyze, and use braking 

status from other ADS-equipped vehicles with at 

least Cooperation Class A capabilities within its 

short-range communications approximately every 

1⁄10 s.

WZM-N1.03 Gather, integrate, process, 

and disseminate work-zone 

information.

WZM-R1.01 An ADS-equipped vehicle with at least 

Cooperation Class A capabilities shall be able to 

receive, decode, process, analyze, and use 

work-zone data (start and end location, lanes 

affected, date/time of work-zone activities, 

associated speed limits prior to and within the 

work zone) obtained from the TMS via 

short-range communications approximately every 

1 s. 

WZM-N1.03 Gather, integrate, process, 

and disseminate work-zone 

information.

WZM-R1.02 An ADS-equipped vehicle with at least 

Cooperation Class A capabilities shall be able to 

receive, decode, process, analyze, and use data 

about the work-zone geographic layout obtained 

from the TMS via short-range communications 

approximately every 1 s. 

WZM-N1.03 Gather, integrate, process, 

and disseminate work-zone 

information.

WZM-R1.04 An ADS-equipped vehicle with at least 

Cooperation Class B capabilities shall be able to 

receive, decode, process, analyze, and use 

work-zone data (start and end location, lanes 

affected, date/time of work-zone activities, 

associated speed limits prior to and within the 

work zone) obtained from the TMS via long-range 

communications approximately every 1 s. 
80 

Operational 

Need 

Identifier Operational Need

Functional 

Requirement

Identifier Functional Requirement

WZM-N1.03 Gather, integrate, process, 

and disseminate work-zone 

information.

WZM-R1.05 An ADS-equipped vehicle with at least 

Cooperation Class B capabilities shall be able to 

receive, decode, process, analyze, and use data 

about the work-zone geographic layout obtained 

from the TMS via long-range communications 

approximately every 1 s. 

WZM-N1.03 Gather, integrate, process, 

and disseminate work-zone 

information.

WZM-R1.10 An ADS-equipped vehicle shall be able to 

interpret the presence of a tapered barrier 

(i.e., channeling devices) in conjunction with a 

traffic light showing green to allow it to cross a 

double yellow line and proceed in the opposing 

driving lane to pass the work-zone area (before 

moving into the opposite direction lane).

WZM-N1.03 Gather, integrate, process, 

and disseminate work-zone 

information.

WZM-R1.07 An ADS-equipped vehicle shall be able to detect, 

decode, process, analyze, and react to the message 

related to the work zone posted on a VMS prior to 

the work zone using visual detection onboard 

sensors and optical code recognition technology.

WZM-N1.03 Gather, integrate, process, 

and disseminate work-zone 

information.

WZM-R1.10 An ADS-equipped vehicle shall be able to 

interpret the presence of a tapered barrier 

(i.e., channeling devices) in conjunction with a 

traffic light showing green to allow it to cross a 

double yellow line and proceed in the opposing 

driving lane to pass the work-zone area (before 

moving into the opposite direction lane).

WZM-N1.04 Receive and process traffic 

SPaT and work-zone 

geographic layout (MAP) 

messages from traffic signals 

controlling the approaches to 

the work zone.

WZM-R1.03 An ADS-equipped vehicle with at least 

Cooperation Class A capabilities shall be able to 

receive, decode, process, analyze, and use 

traffic-signal status data from the traffic light via 

short-range communications approximately every 

1⁄10 s. 

WZM-N1.04 Receive and process traffic 

SPaT and work-zone 

geographic layout (MAP) 

messages from traffic signals 

controlling the approaches to 

the work zone.

WZM-R1.06 An ADS-equipped vehicle with at least 

Cooperation Class B capabilities shall be able to 

receive, decode, process, analyze, and use 

traffic-signal status data from the traffic light via 

long-range communications approximately every 

1⁄10 s.

WZM-N1.05 Location and speed 

information from vehicles 

near ADS-equipped vehicles.

BT-R1.05 An ADS-equipped vehicle with at least 

Cooperation Class A capabilities shall be able to 

receive, decode, process, analyze, and use 

locations, speeds, and headings from other 

ADS-equipped vehicles with at least Cooperation 

Class A capabilities via long-range 

communications within a configurable geofenced 

area approximately every 1⁄10 s.

WZM-N1.05 Location and speed 

information from vehicles 

near ADS-equipped vehicles.

BT-R1.06 An ADS-equipped vehicle with at least 

Cooperation Class A capabilities shall be able to 

receive, decode, process, analyze, and use braking 

status from other ADS-equipped vehicles with at 

least Cooperation Class A capabilities via 

long-range communications within a configurable 

geofenced area approximately every 1⁄10 s.
81 

Operational 

Need 

Identifier Operational Need

Functional 

Requirement

Identifier Functional Requirement

WZM-N1.05 Location and speed 

information from vehicles 

near ADS-equipped vehicles.

WZM-R1.08 An ADS-equipped vehicle with at least 

Cooperation Class A capabilities shall be able to 

broadcast its driving path for the previous 1 min

approximately every 1 s. 

WZM-N1.05 Location and speed 

information from vehicles 

near ADS-equipped vehicles.

WZM-R1.09 An ADS-equipped vehicle with at least 

Cooperation Class B capabilities shall be able to 

broadcast its intended future driving path for at 

least the next 15 s approximately every 3 s.

WZM-N1.06 Detect any workers or TCDs 

encroaching on the travel 

lane.

WZM-R1.14 An ADS-equipped vehicle shall be able to detect 

and either slow down or stop when a worker 

within the work zone steps into the lane in front of 

the ADS-equipped vehicle.

WZM-N1.07 Detect vehicles incapable of 

cooperating with other 

vehicles.

WZM-R1.16 An ADS-equipped vehicle shall be able to use 

onboard sensors to detect the location, speed, and 

heading at suitable sensing intervals of vehicles 

not equipped with ADS with no cooperative 

automation capabilities.

WZM-N1.08 Detect vehicles entering or 

exiting the work zone.

WZM-R1.11 An ADS-equipped vehicle shall be able to detect 

any oncoming vehicles still present in one lane 

before moving into the opposite direction lane.

WZM-N1.08 Detect vehicles entering or 

exiting the work zone.

WZM-R1.12 An ADS-equipped vehicle shall not drive into the 

opposing lane if any oncoming vehicles have been 

detected (and instead stop in its own lane until all 

oncoming vehicles have passed).

WZM-N1.08 Ability to detect vehicles 

entering or exiting the work 

zone.

WZM-R1.13 An ADS-equipped vehicle shall be able to detect 

and either slow down or stop when a work-zone 

vehicle exits the work zone.

WZM-N1.09 Visual alerts upstream and 

when navigating the work 

zone.

WZM-R1.11 An ADS-equipped vehicle shall be able to detect 

any oncoming vehicles still present in the lane 

before moving into the opposite direction lane.

WZM-N1.09 Visual alerts upstream and 

when navigating the work 

zone.

WZM-R1.12 An ADS-equipped vehicle shall not drive into the

opposing lane if any oncoming vehicles have been 

detected (and instead stop in its own lane until all 

oncoming vehicles have passed).

WZM-N1.09 Visual alerts upstream and 

when navigating the work 

zone.

WZM-R1.13 An ADS-equipped vehicle shall be able to detect 

and either slow down or stop when a work-zone 

vehicle exits the work zone.

WZM-N1.09 Visual alerts upstream and 

when navigating the work 

zone.

WZM-R1.14 An ADS-equipped vehicle shall be able to detect 

and either slow down or stop when a worker 

within the work zone steps into the lane in front of 

the ADS-equipped vehicle.

WZM-N1.09 Visual alerts upstream and 

when navigating the work 

zone.

WZM-R1.15 An ADS-equipped vehicle with Cooperation 

Class C capabilities shall be able to send, receive, 

decode, process, analyze, and use detailed 

intention data including ACKs and NAKs when 

cooperating with other ADS-equipped vehicles 

with Cooperation Class C capabilities during the 

work-zone bypass maneuver including interactions 

with work-zone vehicles coming out of or driving 

into the actual work zone.
82 

Operational 

Need 

Identifier Operational Need

Functional 

Requirement

Identifier Functional Requirement

WZM-N1.09 Visual alerts upstream and 

when navigating the work 

zone.

WZM-R1.16 An ADS-equipped vehicle shall be able to use 

onboard sensors to detect the location, speed, and 

heading at suitable sensing intervals of 

non-ADS-equipped vehicles with no cooperative 

automation capabilities. 

WZM-N1.09 Visual alerts upstream and 

when navigating the work 

zone.

BT-R1.16 An ADS-equipped vehicle shall have a means to 

visually display to the driver the location of other 

vehicles about which it has information.

WZM-N1.09 Visual alerts upstream and 

when navigating the work 

zone.

WZM-R1.17 An ADS-equipped vehicle shall be able to detect, 

decode, process, analyze, and use the end of the

work-zone area and merge into the original lane in 

a safe and efficient manner.

WZM-N1.09 Visual alerts upstream and 

when navigating the work 

zone.

WZM-R1.18 An ADS-equipped vehicle shall use the end of the 

work-zone area information to determine how it 

can safely and efficiently resume its previous 

travel speed.

WZM-N1.10 Geofenced work-zone 

information, including speed 

limits to ADS-equipped 

vehicles approaching the 

work zone. 

WZM-R1.19 A TMS shall be able to broadcast a work-zone 

notification message to a geofenced area around 

the work zone. Communications shall be possible 

approximately every 1 s via short- or long-range 

communications to the TMS.

WZM-N1.10 Geofenced work-zone 

information, including speed 

limits to ADS-equipped 

vehicles approaching the 

work zone. 

WZM-R1.20 A TMS shall be able to broadcast the geographic 

layout of the work zone to a geofenced area 

around the work zone. Communications shall be 

possible approximately every 1 s via short- or 

long-range communications to the TMS.

WZM-N1.11 Ability to manage variable 

message signs and other 

traveler information systems 

to provide vehicles 

approaching the work zone

with visual and/or audible 

information about the work 

zone.

WZM-R1.21 A TMS shall be able to post a message on VMS 

prior to the work zone.

WZM-N1.11 Ability to manage variable 

message signs and other 

traveler information systems 

to provide vehicles 

approaching the work zone

with visual and/or audible 

information about the work 

zone.

WZM-R1.22 A TMS shall be able to modify a message posted 

on VMS prior to the work zone.

WZM-N1.11 Ability to manage VMSs and 

other traveler information 

systems to provide vehicles 

approaching the work area 

with visual and/or audible 

information about the work 

zone.

WZM-R1.23 A TMS shall be able to delete a message posted on 

VMS prior to the work zone and display the 

previously displayed message, if applicable. 
83 

Operational 

Need 

Identifier Operational Need

Functional 

Requirement

Identifier Functional Requirement

WZM-N1.12 Gather and process data from 

ITS devices and 

ADS-equipped vehicles to 

monitor current traffic 

conditions.

BT-R1.17 A TMS shall be able to receive aggregated data 

(e.g., locations, speeds, headings, and brake status) 

from each ADS-equipped vehicle with at least 

Cooperation Class A capabilities in a specified 

area. Communications shall be possible 

approximately every 1 s via short- or long-range 

communications to the TMS.

ACK = acknowledgment.

85 

APPENDIX. KEY TSMO STRATEGIES AND THEIR RELATIONSHIP TO 

COOPERATIVE ADS

The TSMO strategies presented in table 26 through table 43 are profiled in tabular format in 

relation to CDA, strategy group, strategy, description, and Cooperation Classes applicable to the 

strategy.

Table 26 presents TSMO strategies for arterial management that provides users with a safe, 

efficient, and reliable trip.

Table 26. TSMO strategies for arterial management. 

ID TSMO Strategies Description

Cooperation 

Class

Additional Benefit to 

Existing TSMO 

Strategy

1-1 Access Management

Related strategies: 

Weather-Related Road 

Restrictions (8-6), Curbside 

Management (17-6)

Access management is the proactive 

management of vehicular access 

points to land parcels adjacent to all 

types of roadways. Techniques to 

control access include, for example,

driveway spacing, safe turning lanes, 

and median treatments.

A, B Improved real-time 

access allocation. 

1-2 Adaptive Signal Timing

Related strategies: 

Transit-Signal Priority (1-5), 

Truck Traffic Signal Priority 

(1-6), Weather-Responsive 

Traffic Signal Control (8-7)

Adaptive traffic signal control is a 

concept for which vehicular traffic in 

a network is detected at an upstream 

and/or downstream point and an 

algorithm is used to predict when the 

traffic will arrive and where the traffic 

will be located. 

A, B Improved real-time 

traffic detection. 

Reduced reliance on 

physical sensor 

devices and 

maintenance. 

Improved algorithms 

to adjust signal timing 

and queue 

management. 

1-3 Signal 

Retiming/Optimization

Related strategies: Signal 

Timing for Bicycles and 

Pedestrians (1-4)

Signal retiming/optimization strategy 

is a concept to optimize traffic flow.

A, B Improved historical 

traffic data for 

nonreal-time 

adjustments. 

Reduced reliance on 

physical sensor 

devices and 

maintenance. 

1-4 Signal Timing for Bicycles 

and Pedestrians

Related strategies: Signal 

Retiming/Optimization (1-3)

Signal timing for bicycles and 

pedestrians is an operational strategy 

for reducing the delay pedestrians and 

bicyclists experience at traffic signals.

A, B Ability to monitor the 

number of vehicles 

versus bicycles and 

pedestrians.

Reduced reliance on 

physical sensor 

devices and 

maintenance. 
86 

ID TSMO Strategies Description

Cooperation 

Class

Additional Benefit to 

Existing TSMO 

Strategy

1-5 TSP

Related strategies: Adaptive 

Signal Timing (1-2)

TSP is an operational strategy for 

reducing the delay transit vehicles 

experience at traffic signals.

A, B, C Improved 

transit-vehicle 

detection. 

Enhanced real-time 

traffic-detection 

algorithms for priority. 

1-6 Truck Traffic Signal 

Priority

Related strategies: Adaptive 

Signal Timing (1-2)

Truck traffic signal priority is an 

operational strategy for reducing the 

delay commercial vehicle operators 

experience at traffic signals.

A, B, C Improved 

freight-vehicle 

detection. 

Enhanced real-time 

traffic-detection 

algorithms for priority. 

TSP = transit-signal priority.

Table 27 presents TSMO strategies for active traffic management (ATM), allowing TSMO 

operators the ability to dynamically manage recurring and nonrecurring congestion based on 

prevailing and predicted traffic conditions. Focusing on trip reliability, ATM maximizes the 

effectiveness and efficiency of the facility.
87 

Table 27. TSMO strategies for ATM.

ID TSMO Strategies Description

Cooperation 

Class

Additional 

Benefit to 

Existing 

TSMO 

Strategy

2-1 Dynamic Junction Control Dynamic junction control consists of 

dynamically allocating lane access on 

mainline and ramp lanes in interchange 

areas in which high traffic volumes are 

present and the relative demand on the 

mainline and ramps change throughout 

the day.

A, B More accurate 

junction 

control. 

High accuracy 

of traffic data 

and demand on 

mainline and 

ramps. 

2-2 Dynamic Merge Control Dynamic merge control consists of 

dynamically managing the entry of 

vehicles into merge areas with a series of 

advisory messages approaching the 

merge point that prepare motorists for an 

upcoming merge and encourage or direct 

consistent merging behavior.

A, B, C Precise merge 

operations. 

Improved 

merge 

consistency. 

2-3 Lane Use Control

Related strategies: 

Traffic-Incident Management 

(11-2), Work-Zone 

Management (15-1)

Lane-use control signals are special 

overhead signals that permit or prohibit 

the use of specific lanes of a street or 

highway or that indicate the impending 

temporary closure of the lanes.

A, B Improved use 

of lane-use 

control based 

on 

high-frequency 

traffic data. 

Improved 

safety for 

Cooperation 

Class B

vehicles. 

2-4 Queue Warning

Related strategies: Motorist 

Advisory and Warning 

Systems (8-2), Break Long 

Queues on Arterials (17-3)

Queue warning systems advise motorists 

of approaching congested work zones, 

predictable bottlenecks, or areas with 

sight-distance limitations of traffic 

stoppage or slowdown. 

A, B Improved 

queue detection 

and location 

accuracy. 

Enhanced 

safety, 

particularly for 

Cooperation 

Class B

vehicles. 

2-5 Reversible Lanes The reversible lanes operational strategy 

allows for the direction of the roadway to 

be reversed depending on traffic demand.

A, B, C Improved 

reversal times 

based on 

additional 

traffic data. 

Improved 

conflict 

detection. 

Improved 

warning 

systems. 
88 

ID TSMO Strategies Description

Cooperation 

Class

Additional 

Benefit to 

Existing 

TSMO 

Strategy

2-6 Ramp Metering Ramp meters are traffic signals installed 

on freeway onramps to control the 

frequency at which vehicles enter the 

flow of traffic on the freeway. Ramp 

metering reduces overall freeway 

congestion by managing the volume of 

traffic entering the freeway and by 

breaking up platoons that make it 

difficult to merge onto the freeway.

A, B, C Improved 

mainline 

detection. 

Improved queue 

detection. 

Enhanced 

safety, 

particularly for 

Cooperation

Class B

vehicles. 

2-7 Real-Time Traffic 

Monitoring

Related strategies: Multimodal 

Regional Traveler Information 

(12-1), Real-Time Transit 

Arrival Information (12-4)

Real-time traffic monitoring is a strategy 

whereby traffic is monitored in real time 

through sensors, field devices, and 

third-party data to assist in ATM. 

A, B More 

comprehensive 

coverage for 

monitoring the 

roadway 

network and 

multiple modes. 

2-8 Speed Harmonization

Related strategies: Weather 

Speed Advisories (8-10), 

Lateral Vehicle Formations 

(17-14), Weather-Responsive 

VSL Application (8-10)

Speed harmonization (i.e., VSLs) is a 

strategy for managing traffic flow and 

congestion whereby the speed is adjusted 

based on traffic and weather conditions.

A, B Improved speed 

harmonization 

due to 

high-frequency 

data. 

Enhanced 

safety, 

particularly for 

Cooperation

Class B

vehicles. 

2-9 Shoulder Lanes

Related strategies: 

Traffic-Incident Management 

(11-2), Work-Zone 

Management (15-1), Special 

Event Management (10-1)

This strategy enables the use of the 

shoulder as a travel lane, known as Hard 

Shoulder Running or temporary shoulder 

use, the strategy is typically applied 

according to congestion levels during 

peak periods and in response to incidents 

or other conditions as warranted during 

nonpeak periods.

A, B Improved 

location-based 

detection of 

congestion 

levels. 

High-frequency 

data used to 

adjust when to 

implement 

hard-shoulder 

running. 

Enhanced 

safety. 

Table 28 presents TSMO strategies for congestion pricing, which encompasses roadway pricing 

that varies by the time of the day and the level of congestion on the facility. 
89 

Table 28. TSMO strategies for congestion pricing. 

ID TSMO Strategies Description

Cooperation 

Class

Additional 

Benefit to 

Existing 

TSMO 

Strategy

3-1 Areawide Charging

Related strategies: Cordon 

Charging (3-2), Electronic Toll 

Collection (3-3), Variable Tolls 

(3-4)

This strategy involves per-unit charges 

within a given geographical area.

Charges are typically based on miles 

traveled or zones crossed.

A, B Personalized 

tolling. 

Tolls based on 

vehicle 

attributes and 

number of 

occupants. 

3-2 Cordon Charging

Related strategies: Areawide 

Charging (3-1), Electronic Toll 

Collection (3-3), Variable Tolls 

(3-4)

This strategy charges motorists for 

driving in congested core locations.

A, B Personalized 

tolling. 

Tolls based on 

vehicle 

attributes and 

number of 

occupants. 

3-3 Electronic Toll Collection

Related strategies: Areawide 

Charging (3-1), Cordon 

Charging (3-2), 

High-Occupancy Toll Lanes 

(7-1)

This strategy uses electronic methods 

for collecting tolls to avoid delays 

associated with cash-based tolls.

A, B Potential to 

reduce tolling 

infrastructure. 

3-4 Variable Tolls

Related strategies: Areawide 

Charging (3-1), Cordon 

Charging (3-2), Electronic Toll 

Collection (3-3), 

High-Occupancy Toll Lanes 

(7-1)

This strategy changes the toll fee, in real

time, based on the level of traffic 

demand on the lanes.

A, B Improved 

high-frequency 

data for use in 

adjusting price 

based on 

demand. 

More granular 

toll rates. 

Variable tolls 

based on 

vehicle 

attributes. 

Table 29 presents TSMO strategies for emergency transportation operations, which provides 

users with a safe and efficient transportation system during emergency situations. 
90 

Table 29. TSMO strategies for emergency transportation operations. 

ID TSMO Strategies Description

Cooperation 

Class

Additional 

Benefit to 

Existing 

TSMO 

Strategy

4-1 Evacuation Management

Related strategies: Agency 

Coordination and Integration 

(18-9), Decision Support 

System (6-1), Freeway/Arterial 

Integrated Corridor 

Management (6-2), Mass 

Media Communication (18-4), 

Emergency Preparedness (4-2)

Evacuation management involves a 

predefined set of procedures to assist in a 

safe and efficient evacuation.

A, B, C Improved 

evacuation 

strategy based 

on vehicle 

data. 

Improved 

safety 

particularly 

for 

Cooperation

Class B

vehicles. 

4-2 Emergency Preparedness

Related strategies: Evacuation 

Management (4-1), Emergency 

Response (4-3), Decision 

Support System (6-1)

This strategy relates to the activities, 

programs, and systems developed prior to 

an incident, disaster, or emergency, 

which are used to support and enhance 

prevention, response, and recovery. 

Preparedness efforts depend on the 

resources and risks of a jurisdiction or 

region.

A Improved 

emergency 

preparedness 

through use of 

status data. 

4-3 Emergency Response

Related strategies: 

Traffic-Incident Management 

(11-2), Decision Support 

System (6-1), Computer-Aided 

Dispatch Integration with 

Traffic Management Center 

Operations (18-1), Evacuation 

Management (4-1), Emergency 

Preparedness (4-2), Incident 

Scene Pre-arrival Staging 

Guidance for Emergency 

Responders (RESP-STG) 

(16-4), Emergency Path 

Clearance (17-11), Safety 

Buffer (17-18), Lane Clear 

(17-13)

This strategy involves the Traffic 

Management Centers operational 

response to emergency incidents and 

disasters.

A, B, C Improved 

safety from 

additional 

traffic data. 

Improved 

safety 

particularly 

for 

Cooperation 

Class B

vehicles. 

Optimized 

emergency 

routing. 

Table 30 presents TSMO strategies for freight technology and operations, which focus on the 

effective management of the system for freight transportation. The goal of freight transportation 

is to move goods safely, efficiently, and reliably throughout the region. This goal may range 

from satisfying customers (e.g., freight shippers, receivers, and carriers) to actual travel time on 

the system.
91 

Table 30. TSMO strategies for freight technology and operations. 

ID TSMO Strategies Description

Cooperation 

Class

Additional 

Benefit to 

Existing 

TSMO 

Strategy

5-1 Fleet Management

Related strategies: 

Full-Function Service Patrols 

(11-1), Route Optimization for 

Snowplows (8-4), Automated 

Maintenance and 

Fleet-Management Systems 

(17-1)

This strategy involves location tracking 

and route planning for commercial and

DOT-owned vehicles.

A, B Improved 

fleet 

management 

from location 

data. 

Optimized 

route 

planning from 

additional 

traffic data. 

5-2 Commercial Motor Vehicle 

Electronic 

Screening/Clearance

Related strategies: 

Weather-Related Vehicle 

Restrictions (8-8), Digital 

Infrastructure Messaging 

(17-8), Lanes Dedicated as 

Transit or Trucks Only (7-3), 

Weather-Related Road 

Restrictions (8-6)

This strategy uses electronic 

screening/clearance of freight vehicles, 

including size and weight restrictions.

A, B Automatic 

electronic 

screening and 

clearance of 

vehicle 

attributes. 

Ability to 

reduce travel 

time. 

Ability to 

charge fees 

based on O-D 

and vehicle 

attributes. 

DOT = department of transportation; O-D = origin–destination.

Table 31 presents TSMO strategies for integrated corridor management, an approach that focuses 

on collaborative management of the transportation corridor as a system rather than the more 

traditional approach of managing individual assets on the corridor. Partners manage the corridor 

as an integrated asset to improve travel-time reliability and predictability, help manage 

congestion, and empower travelers through better information and more choices.
92 

Table 31. TSMO strategies for integrated corridor management. 

ID TSMO Strategies Description

Cooperation 

Class

Additional Benefit to 

Existing TSMO 

Strategy

6-1 Decision Support System

Related strategies: 

Automated Maintenance 

Decision Support System 

(17-2), Evacuation 

Management (4-1), 

Emergency Preparedness 

(4-2), Emergency Response 

(4-3), Traffic-Incident 

Management (11-2), 

Freeway/Arterial Integrated 

Corridor Management (6-2)

Decision support system employs a 

decision algorithm for incident 

response that typically includes 

expert rules, prediction, and 

evaluation based on numerous data 

inputs.

A, B, C Improved traffic flow 

from additional 

high-frequency data. 

Improved safety 

through optimized 

decision-support 

algorithms from 

additional data. 

6-2 Freeway/Arterial ICM

Related strategies: all

Freeway/arterial ICM involves the 

combined application of technologies 

and integration of various TSMO 

strategies and network partners, all 

working together to optimize traffic 

flow in a corridor.

A, B, C Improved alternate 

routes.

Creates benefits to load 

balancing. 

Improved safety 

through additional data 

inputs. 

Table 32 presents TSMO strategies for managed lanes, which are highway facilities or a set of 

lanes in which operational strategies are proactively implemented and managed in response to 

changing conditions. 
93 

Table 32. TSMO strategies for managed lanes. 

ID TSMO Strategies Description

Cooperation 

Class

Additional Benefit to 

Existing TSMO 

Strategy

7-1 High-Occupancy Toll 

Lanes

Related strategies: 

Electronic Toll 

Collection (3-3), 

Variable Tolls (3-4)

This strategy involves any HOT lane 

that allows vehicles not meeting 

minimum occupancy requirements to 

use the lane by paying a toll.

A, B Optimized HOT

activation based on 

additional 

high-frequency traffic 

data. 

Granular toll rates. 

Tolls based on vehicle 

attributes and number of 

occupants. 

7-2 High-Occupancy 

Vehicle Lanes

This strategy involves a preferential 

lane designated for exclusive use by 

vehicles with two or more occupants 

for all or part of a day, including a 

designated lane on a freeway, 

highway, street, or independent 

roadway on a separate right-of-way.

A Number-of-occupants 

detected.

Improved HOV 

effectiveness and 

optimization planning 

based on additional 

traffic data. 

7-3 Lanes Dedicated as 

Transit or Commercial 

Motor Vehicle Only

Related strategies: 

Digital Infrastructure 

Messaging (17-8), 

Roadside Truck 

Electronic 

Screening/Clearance 

(5-2)

This strategy focuses on lanes 

dedicated to transit or freight 

vehicles.

A, B, C Ability to provide lane 

guidance to transit and 

trucks. 

Reduced need for 

infrastructure 

investments. 

Table 33 presents TSMO strategies for road weather management that focus on providing users 

with a safe and efficient transportation system during and after weather events. 
94 

Table 33. TSMO strategies for road weather management. 

ID TSMO Strategies Description

Cooperation 

Class

Additional Benefit to 

Existing TSMO 

Strategy

8-1 En Route Weather 

Alerts and Pavement 

Condition Information

Related strategies: 

Multimodal Regional 

Traveler Information 

(12-1)

En route weather alerts and 

pavement-condition information 

involve active alerts based on a 

particular route.

A, B More accurate 

location-based weather 

data. 

Improved safety for 

Cooperation Class B

vehicles through 

in-vehicle notifications. 

8-2 Motorist Advisory and 

Warning Systems

Related strategies: Queue 

Warning (2-4), 

Multimodal Regional 

Traveler Information 

(12-1), Cooperative 

Weather-Responsive 

Conflict Management 

(17-5)

This strategy collects and processes 

data to develop warnings based on 

weather conditions.

A, B Personalized advisories 

and warnings based on 

vehicle attributes. 

More accurate 

confirmation of hazard 

types. 

More timely warnings. 

8-3 Pretrip Condition 

Information and 

Forecast Systems

Related strategies: 

Predictive Traveler 

Information (12-3)

Pretrip condition information and 

forecast systems involve using

weather data to predict conditions 

prior to a trip.

A, B Improved weather 

predictions from 

additional weather data.

Warnings based on 

vehicle type and route 

for Cooperation Class B

vehicles. 

8-4 Route Optimization for 

Snowplows

Related strategy: Fleet 

Management (5-1)

This strategy involves dynamic 

optimization of snowplows based on 

traffic demand to minimize impact to 

a region.

A, B, C Route optimization for 

snowplows based on 

additional traffic data. 

Increased roadway 

prioritization based on 

vehicle data. 

8-5 Winter Operations

Related strategy: 

Weather-Related Road 

Restrictions (8-6)

This strategy includes several

activities that an organization 

performs to prepare or address 

adverse winter conditions, such as 

salting the roadway and removing 

snow.

A, B, C Better operations from 

additional 

high-frequency data. 

8-6 Weather-Related Road 

Restrictions

Related strategies: 

Access Management 

(1-1), Digital 

Infrastructure Messaging 

(17-8), Roadside Truck 

Electronic 

Screening/Clearance 

(5-2), Winter Operations 

(8-5)

This strategy limits access to roads 

based on weather conditions.

A, B Personalized warnings 

based on vehicle type 

and route for 

Cooperation Class B 

vehicles. 

Faster identification of 

roads that should be 

restricted based on 

weather conditions. 
95 

ID TSMO Strategies Description

Cooperation 

Class

Additional Benefit to 

Existing TSMO 

Strategy

8-7 Weather-Responsive 

Traffic Signal Control

Related strategies: 

Adaptive Signal Timing 

(1-2), Cooperative 

Weather-Responsive 

Conflict Management 

(17-5)

This strategy adjusts signal controls 

based on current weather conditions.

A, B Automatic adjustment 

based on more accurate 

location-based weather 

data. 

Ability to consider

vehicle attributes. 

8-8 Weather-Related 

Vehicle Restrictions

Related strategies: 

Roadside Truck 

Electronic 

Screening/Clearance 

(5-2), Digital 

Infrastructure Messaging 

(17-8)

This strategy uses vehicle attributes to 

determine applicable 

weather-condition restrictions.

A, B Improved identification 

of vehicles based on 

attributes. 

Personalized restrictions. 

8-9 Weather Speed 

Advisories

Related strategy: Speed 

Harmonization (Variable 

Speed Limits) (2-8)

Weather speed advisories are used as 

a safety application to advise drivers 

on a safe speed under the prevailing 

weather conditions.

A, B Refined weather 

advisories based on 

additional weather data 

from connected vehicles. 

Improved targeted 

advisory delivery for 

Cooperation Class B

vehicles. 

8-10 Weather-Responsive 

VSL Application

Related strategy: Speed 

Harmonization (Variable 

Speed Limits) (2-8)

This strategy consists of multiple 

roadside-monitoring and display 

trailers capable of detecting weather 

and traffic data.

A, B Speed harmonization 

during adverse road 

weather events to 

streamline traffic and 

improve safety. 

Table 34 presents TSMO strategies for safety management measures.
96 

Table 34. TSMO strategies for safety management. 

ID TSMO Strategies Description

Cooperation 

Class

Additional Benefit to 

Existing TSMO Strategy

9-1 Bicycle Detection/Warning

Related strategy: Intersection 

Warnings (9-3)

This strategy includes a 

detection and warning 

system to alert drivers of 

potential cyclists.

A, B Faster object detection 

alerting. 

Improved targeted 

warnings based on 

location, speed, and 

vehicle attributes. 

9-2 Geometry Warnings This strategy includes a 

warning system to alert 

drivers of geometric 

dangers, such as a sharp 

curve.

A, B Identification of 

geometric dangers. 

Personalized, targeted 

warnings based on 

vehicle attributes. 

9-3 Intersection Warnings

Related strategies: Bicycle 

Detection/Warning (9-1), 

Pedestrian Detection/Warning 

(9-4), Red-Light Violation 

Warning (16-5), Intersection 

Conflict Management (17-12)

This strategy involves 

warning systems at 

intersections to provide 

supplemental safety-related 

information, such as 

traffic-light status.

A, B Benefit from providing 

fast notifications to each 

vehicle depending on 

location and vehicle 

attributes. 

9-4 Pedestrian Detection/Warning

Related strategy: Intersection 

Warnings (9-3)

This strategy includes a 

detection and warning 

system to alert drivers to 

pedestrians crossing the 

road.

A, B Improved pedestrian 

detection. 

Targeted warnings. 

Table 35 presents TSMO strategies for special event management, including sporting events, 

concerts, festivals, and conventions occurring at permanent multiuse venues (e.g., arenas, 

stadiums, racetracks, fairgrounds, amphitheaters, convention centers). 

Table 35. TSMO strategies for special event management. 

ID TSMO Strategies Description

Cooperation 

Class

Additional Benefit to 

Existing TSMO Strategy

10-1 Special Event Management

Related strategies: Mass Media 

Communication (18-4), Shoulder 

Lanes (2-9), Traffic-Incident 

Management (11-2)

This strategy involves 

changing related strategies 

to account for a planned 

event based on anticipated 

impacts on traffic flow.

A, B, C Improved traffic routing. 

Improved predictions 

based on high-resolution 

traffic data. 

Additional safety from 

in-vehicle guidance, 

particularly for 

Cooperation Class B

vehicles. 

Table 36 presents TSMO strategies for TIM, which consists of a planned and coordinated 

multidisciplinary process to detect, respond to, and clear traffic incidents so that traffic flow may 

be restored as safely and quickly as possible. 
97 

Table 36. TSMO strategies for TIM.

ID TSMO Strategies Description

Cooperation 

Class

Additional Benefit to 

Existing TSMO Strategy

11-1 Full-Function Service Patrols

Related strategy: Fleet 

Management (5-1)

Service patrols are 

usually operated 

directly by or under 

contract to a State 

DOT. As such, the 

patrol can be the 

onscene “eyes and 

ears” for a TMC, 

increasing the 

promptness and 

accuracy of 

information about 

an incident's impact 

to the traveling 

public.

A, B Faster response time. 

Personalized vehicle 

guidance. 

Improved routing. 

11-2 Traffic-Incident Management

Related strategies: Lane Use 

Control (2-3), Shoulder Lanes 

(2-9), Computer-Aided 

Dispatch (CAD) Integration 

With Traffic Management 

Center (TMC) Operations 

(18-1), Decision Support 

System (6-1), Multimodal 

Regional Traveler Information 

(12-1), Emergency Response 

(4-3), Incident Scene Prearrival 

Staging Guidance For 

Emergency Responders 

(RESP-STG) (16-4), Dynamic 

Route Guidance (17-10), 

Disabled Vehicle Beacon 

(17-9), Lane Clear (17-13), 

Safety Buffer (17-18), 

Emergency Path Clearance 

(17-11), Quick Clearance 

Policies (18-2), Wrecker 

Response Contracts (18-3), 

Special Event Management 

(10-1), Freeway/Arterial ICM 

(6-2)

TIM consists of a 

planned and 

coordinated 

multidisciplinary 

process to detect, 

respond to, and 

clear traffic 

incidents so that 

traffic flow may be 

restored as safely 

and quickly as 

possible. Applied 

effectively, TIM 

reduces the 

duration and 

impacts of traffic 

incidents and 

improves the safety 

of motorists, crash 

victims, and 

emergency 

responders.

A, B, C Optimized response based on 

additional traffic data. 

Improved onsite monitoring. 

Increased safety and advanced 

notifications based on 

Cooperation Class B

cooperation. 

Improved safety and mobility. 

Increased productivity. 

DOT = department of transportation.

Table 37 presents TSMO strategies for traveler information, designed to provide transportation 

system users with the information they need to choose the safest and most efficient mode and 

route of travel.
98 

Table 37. TSMO strategies for traveler information.

ID TSMO Strategies Description

Cooperation 

Class

Additional Benefit to 

Existing TSMO Strategy

12-1 Multimodal Regional 

Traveler Information

Related strategies: En Route 

Weather Alerts and Pavement 

Condition Information (8-1), 

Traffic-Incident Management 

(11-2), Real-Time Traffic 

Monitoring (2-7), Special 

Event Management (10-1), 

Real-Time Transit Arrival 

Information (12-4), Motorist 

Advisory and Warning 

Systems (8-2), Queue Warning

(2-4) 

This strategy provides 

real-time information 

to travelers, allowing 

them to reschedule or 

reroute trips away 

from traffic incidents, 

construction zones, 

road closures, and 

transit service 

changes, thereby 

improving travel time 

reliability, safety, and 

quality of life.

A, B High-resolution real-time 

traffic and weather data. 

Improved safety messages 

based on additional data 

attributes. 

Personalized traveler 

information based on O-D 

and vehicle attributes. 

12-2 Parking Availability 

Information and Guidance

Related strategies: none

This strategy uses 

parking-space 

detection technology 

to gather and 

disseminate 

information to assist 

drivers in finding 

parking in a safe and 

efficient manner.

B Improved parking availability 

identification. 

Personalized parking 

information based on vehicle 

attributes or expected time of 

arrival. 

Increased ability to predict 

parking availability. 

12-3 Predictive Traveler 

Information

Related strategy: Pretrip 

Condition Information and 

Forecast Systems (8-3)

This strategy uses 

historical and realtime data to predict 

and notify the driver 

regarding anticipated 

travel times.

A, B Additional high-resolution 

data for machine learning 

prediction applications. 

Improved safety messages 

based on additional data 

attributes. 

12-4 Real-Time Transit Arrival 

Information

Related strategies: Real-Time 

Traffic Monitoring (2-7), 

Multimodal Regional Traveler 

Information (12-1), Advanced 

Transit Operations (14-1)

This strategy uses 

historical and 

real-time data to 

predict transit arrival 

times.

A, B Improved transit arrival 

predictions from additional 

data. 

O-D = origin–destination.

Table 38 presents TSMO strategies for travel demand management, which provides users with 

effective travel choices to shift or reduce the demand for travel under congested conditions. 
99 

Table 38. TSMO strategies for travel demand management. 

ID TSMO Strategies Description

Cooperation 

Class

Additional Benefit to 

Existing TSMO Strategy

13-1 Commuter Incentives

Related strategy: none

This strategy involves 

incentives for 

commuters to choose 

alternate 

transportation 

methods, such as 

transit or carpools, to 

alleviate congestion in 

a particular location.

B Enhanced ridership. 

13-2 First-Mile/Last-Mile 

Connectivity

Related strategy: none

This strategy uses 

ride-shares, bikes, 

scooters, and so on, to 

provide transportation 

between parking or 

transit locations and 

final destinations.

B Enhanced first-mile/last-mile 

connections by using O-D 

data. 

13-3 Rideshare System

Related strategy: none

This strategy 

encourages the use of 

third-party rideshare 

systems.

A, B Improved rideshare 

opportunities based on O-D 

information. 

O-D = origin–destination. 

Table 39 presents TSMO strategies for transit operations and management, which focus on the 

operation and management of the transit system in a safe and efficient manner.

Table 39. TSMO strategies for transit operations and management. 

ID TSMO Strategies Description

Cooperation 

Class

Additional Benefit to 

Existing TSMO Strategy

14-1 Advanced Transit 

Operations

Related strategies: Real-Time 

Transit Arrival Information 

(12-4), High-Performance 

Transit (14-2)

This strategy involves 

operational 

techniques intended to 

maximize transit 

efficiency.

A, B Improved operations based on 

additional traffic data. 

Improved safety through 

warning systems. 

14-2 High-Performance Transit

Related strategies: Advanced 

Transit Operations (14-1), 

Real-Time Transit Arrival 

Information (12-1)

This approach 

involves the 

development and use 

of high-performance 

strategies to 

encourage commuters 

to use transit.

A, B Optimization of transit 

schedules based on additional 

traffic demands and O-D data. 

O-D = origin–destination. 

Table 40 presents TSMO strategies for WZM, which involves organizing and operating areas 

under construction to minimize traffic delays, maintain safety for workers as well as travelers, 

and accomplish the work efficiently.
100 

Table 40. TSMO strategies for WZM. 

ID TSMO Strategies Description

Cooperation 

Class

Additional Benefit to 

Existing TSMO 

Strategy

15-1 Work-zone Management

Related strategies: 

Lane-Use Control (2-3), 

Shoulder Lanes (2-9), 

Agency Coordination and 

Integration (18-9)

This strategy focuses on 

managing traffic during 

construction to minimize traffic 

delays, maintain motorist and 

worker safety, complete 

roadwork in a timely manner, 

and maintain access for 

businesses and residents.

A, B, C Improved work-zone 

safety. 

Personalized warnings 

based on vehicle 

attributes. 

Improved work-zone 

vehicle guidance. 

Table 41 presents other TSMO strategies.

Table 41. Other TSMO strategies. 

ID TSMO Strategies Description

Cooperation 

Class

Additional Benefit to 

Existing TSMO 

Strategy

16-1 Asset Management

Related strategies: 

Freeway/Arterial ICM 

(6-2), TIM (11-2)

Asset management is the 

strategic and systematic process 

of operating, maintaining, 

upgrading, and expanding 

physical assets.

A, B Improved traffic 

management. 

16-2 Bottleneck Mitigation

Related strategies: none

This strategy involves changes 

to alleviate bottleneck locations 

within a corridor/region. 

Recurring bottlenecks often 

require physical changes to the 

roadway. Temporary 

management of a bottleneck 

issue can be done by using

cooperative vehicle data.

A, B, C Improved bottleneck 

alleviation. 

16-3 Data Marts and Data 

Warehouses

Related strategies: all

This strategy designs and builds 

a data warehouse to collect data 

that can be used by most other 

strategies.

A, B Improved strategies by 

using high-resolution 

data. 

Enable data sharing 

between agencies. 

16-4 Incident Scene 

Prearrival Staging 

Guidance for 

Emergency Responders 

(RESP-STG)

Related strategies: 

Emergency Response 

(4-3), Traffic-Incident 

Management (11-2), 

Emergency Path 

Clearance (17-11), Lane 

Clear (17-13), Safety 

Buffer (17-18)

This strategy involves guidance 

from the TMS regarding 

coordination at the incident 

scene by using connected 

vehicle data.

A, B Improved emergency 

response. 

Increased safety. 
101 

ID TSMO Strategies Description

Cooperation 

Class

Additional Benefit to 

Existing TSMO 

Strategy

16-5 Red-Light Violation 

Warning

Related strategy: 

Intersection Warnings 

(9-3)

This strategy provides advanced 

warning to vehicles based on 

their speed as they approach 

intersections with a red traffic 

signal status.

A, B Increased safety. 

Table 42 presents the potential new TSMO strategies and relationship to CDA. 

Table 42. Potential new TSMO strategies and relationship to CDA data. 

ID TSMO Strategies Description

Cooperation 

Class

17-1 Automated Maintenance and 

Fleet-Management Systems

Related strategy: Fleet Management 

(5-1)

This strategy automates the scheduling of 

vehicle maintenance, ordering materials, and 

deploying assets to the required locations.

A, B

17-2 Automated Maintenance Decision 

Support System

Related strategy: Decision Support 

System (6-1)

This strategy uses, optimizes, and automates 

maintenance decision support systems 

through cooperative automation.

A, B

17-3 Break Long Queues on Arterials

Related strategy: Queue Warning (2-4)

This strategy supports breaking long queues 

on arterials to allow side-street vehicle 

crossing/merging.

B, C

17-4 Cooperative Lane-Balancing

Related strategy: none

This strategy uses the interaction between 

TMSs and CDA to “lane-balance” the traffic 

loads across lanes.

B, C

17-5 Cooperative Weather-Responsive 

Conflict Management

Related strategies: Weather-Responsive 

Traffic-Signal Control (8-7), Motorist 

Advisory and Warning Systems (8-2)

This strategy enables cooperative 

weather-responsive conflict management for 

intersections between infrastructure and 

CDA vehicles.

B, C

17-6 Curbside Management

Related strategy: Access Management 

(1-1)

This strategy manages and optimizes curb 

demand to provide reliable access.

B, C

17-7 Dedicated ADS Lanes

Related strategies: none

This strategy dedicates a lane to ADS to 

encourage and optimize the benefits to 

support freeway capacity.

A, B, C

17-8 Digital Infrastructure Messaging

Related strategy: all

This strategy involves TMSs sharing 

regulatory information digitally within a 

geofenced location based on vehicle 

attributes to support TSMO strategies.

A, B

17-9 Disabled Vehicle Beacon

Related strategy: Traffic-Incident 

Management (11-2)

This strategy uses cooperative 

communication to broadcast information 

regarding a disabled vehicle approaching 

CDA vehicles.

A 
102 

ID TSMO Strategies Description

Cooperation 

Class

17-10 Dynamic Route Guidance

Related strategy: Traffic-Incident 

Management (11-2)

Dynamic route guidance is a strategy that 

augments a user's navigation with real-time 

traffic, transit, and road condition 

information from a TMS or third-party 

company to assist with route guidance. This 

strategy may also include instructions and 

guidance to balance traffic flows (dynamic 

traffic assignment).

B 

17-11 Emergency Path Clearance

Related strategies: Traffic-Incident 

Management (11-2), Emergency 

Response (4-3), Safety Buffer (17-18), 

Lane Clear (17-13), Incident Scene 

Prearrival Staging Guidance for 

Emergency Responders (RESP-STG) 

(16-4)

This strategy involves clearing a path ahead 

to decrease response time for emergency 

responders.

B, C

17-12 Intersection Conflict Management

Related strategy: Intersection Warnings 

(9-3)

This strategy uses cooperative vehicle data 

to give advanced warning of potential 

collisions at intersections. The strategy may 

also include communications with CDA to 

prevent collisions at intersections by 

enhanced communications, negotiations, and 

predictive path trajectory sharing between 

other vehicles and the infrastructure.

B, C

17-13 Lane Clear

Related strategies: Traffic-Incident 

Management (11-2), Safety Buffer 

(17-18), Emergency Path Clearance 

(17-11), Emergency Response (4-3), 

Incident Scene Prearrival Staging 

Guidance for Emergency Responders 

(RESP-STG) (16-4)

This strategy involves safe lane clearing 

using location-based data and CDA to assist 

in clearing a lane for emergency vehicles.

B, C

17-14 Lateral Vehicle Formations

Related strategy: Speed Harmonization

(2-8)

This strategy coordinates the operation of 

vehicles traveling side-by-side in adjacent 

lanes (sometimes referred to as lateral 

platooning). Variable speed limits.

B, C

17-15 Perceived Lane Capacity

Related strategies: none

This strategy provides lane-level speed data 

and occupancy data from perception sensors 

shared from CDA vehicles.

A, B

17-16 Railroad-Crossing Conflict 

Management

Related strategies: none

This strategy uses CDA to coordinate 

potential railroad-crossing conflicts.

B 

17-17 Safe Stop

Related strategies: none

This strategy involves law enforcement 

safely stopping ADS or CDA vehicles.

B, C

17-18 Safety Buffer

Related strategies: Traffic-Incident 

Management (11-2), Lane Clear 

(17-13), Emergency Path Clearance 

(17-11), Emergency Response (4-3), 

Incident Scene Prearrival Staging 

Guidance for Emergency Responders 

(RESP-STG) (16-4)

This strategy uses cooperative 

communications to broadcast a safety-zone 

geofence around first responders to enforce 

Move-Over laws.

B, C
103 

ID TSMO Strategies Description

Cooperation 

Class

17-19 Vehicle Platooning

Related strategies: none

This strategy coordinates the operation of 

vehicles traveling very closely behind each 

other at high speeds.

B, C

Table 43 presents TSMO strategies not expected to be impacted by CDA. 

Table 43. TSMO strategies not expected to be impacted by CDA data. 

ID TSMO Strategies Description

18-1 Computer-Aided Dispatch Integration 

with Operations

Related strategies: Traffic-Incident 

Management (11-2), Emergency Response 

(4-3)

This strategy integrates data between TMSs and CAD 

databases; it helps incident responders to collaborate, 

reducing response time and aiding in incident 

management.

18-2 Quick-Clearance

Related strategy: Traffic-Incident 

Management (11-2)

Quick-clearance policies provide a set of guidelines to 

ensure the safe, efficient removal of vehicles involved in 

an incident from impeding traffic.

18-3 Wrecker Response Contracts

Related strategy: Traffic-Incident 

Management (11-2)

This strategy pertains to contracts with towing companies 

for removal of wrecked or disabled vehicles and debris 

from the incident scene.

18-4 Mass Media Communication

Related strategies: Evacuation Management 

(4-1), Special Event Management (10-1)

This strategy involves traditional advertising methods, 

such as radio, TV, or Internet, to reach drivers with safety 

warnings.

18-5 Traveler Information Marketing 

Campaigns

Related strategies: none

This strategy publishes and markets traveler information 

through a variety of means including print, Internet, and 

other media outlets to ensure travelers are aware of 

available options.

18-6 Employer Programs

Related strategies: none

This strategy involves employers assisting staff with 

subsidized travel options to encourage the use of public 

transport, carpools, and so on. 

18-7 Telecommuting

Related strategies: none

This strategy involves individuals working remotely.

18-8 Urban Centers, Corridor, and Industrial 

Area Investments

Related strategies: none

This strategy involves roadway design improvements.

18-9 Agency Coordination and Integration

Related strategies: Evacuation Management 

(4-1), Freeway/Arterial Integrated Corridor 

Management (6-2), Road Weather 

Management (8)

Agency coordination and integration involves 

communications between departments to optimize relevant 

regional strategies.

18-10 Unmanned Aerial Systems Detection and 

Monitoring

Related strategies: none

This strategy uses tethered and relay drones to detect and 

monitor incidents.

CAD = computer-aided dispatch.

105 

ACKNOWLEDGMENTS

This project was possible with the assistance of representatives from the following organizations:

• Arizona Department of Transportation (DOT). 

• Iowa DOT. 

• Maricopa DOT, Arizona. 

• Maryland DOT. 

• Michigan DOT. 

• Minnesota DOT.

• Nevada DOT. 

• New Jersey DOT. 

• Pennsylvania DOT.

• Texas DOT. 

• Utah DOT. 

• Virginia DOT. 

• Contra Costa Transportation Authority. 

• Maryland Transportation Authority. 

• Auburn University. 

• Carnegie Mellon University. 

• Iowa State University. 

• Old Dominion University. 

• Purdue University. 

• Texas A&M University. 

• University at Buffalo, the State University of New York. 

• University of Arizona. 

• University of California, Berkeley. 

• University of California, Irvine. 

• University of California, Riverside. 

• University of Cincinnati. 

• University of Maryland. 

• University of South Florida. 

• Virginia Tech University.

• American Association of State Highway and Transportation Officials. 

• Baltimore Metropolitan Council. 

• Maryland Center for Advanced Transportation Technology. 

• Road Commission for Oakland County. 

• Texas A&M Transportation Institute. 

• University of Michigan Transportation Research Institute. 

• University of North Carolina Highway Safety Research Center. 

107

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https://standards.its.dot.gov/DevelopmentActivities/CVReference, last accessed 

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*Revised 02/09/2021.


HRDO-20/12-20(20)E Recycled

Recyclable