Speed Management Toolkit

FHWA Safety Program

http://safety.fhwa.dot.gov
This page intentionally left blank. 
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Contents

Tables.....................................................................................................................................................................................................ii

Introduction to the Speed Management Toolkit.................................................................................................................................. 1

Annotated Bibliography of Key Speed Management Resources.......................................................................................................... 2

Speed Management Countermeasures.............................................................................................................................................. 15

Keys to Successful Speed Management Programs Tip Sheets ........................................................................................................... 51
ii

Tables

Table 1. Speed Management Resources - Annotated Bibliography................................................................................................................. 2

Table 2. Matrix of Speeding-related Crash Countermeasures. ...................................................................................................................... 16

Table 3. Potential Crash Effects for Design and Traffic Calming Treatments................................................................................................. 21

Table 4. Potential Speed Reductions for Design and Traffic Calming Measures............................................................................................ 33

Table 5. Potential Crash Effects for Pavement Treatments, Markings and Signs. ......................................................................................... 36

Table 6. Potential Speed Reductions for Pavement Treatments, Markings and Signs. ................................................................................. 40

Table 7.Potential Crash Effects for Traffic Speed Management and Operations Measures.......................................................................... 43

Table 8. Potential Crash Effects for Enforcement and Publicity Countermeasures. ...................................................................................... 46

Table 9. Potential Injury Crash Effects (CMFs) of Changes in Average Operating Speed for a Road Section. [Adapted from Table 3E-2. 

Crash Modification Factors for Changes in Average Operating Speed, Highway Safety Manual, AASHTO, 2010, p. 3-57.] .................. 50

Table 10. Potential Fatal Crash Effects (CMFs) of Changes in Average Operating Speed for a Road Section. [Adapted from Table 3E-2. 

Crash Modification Factors for Changes in Average Operating Speed, Highway Safety Manual, AASHTO, 2010, p. 3-57.] 43................ 50
1

Introduction to the Speed Management Toolkit

This package of speed management resources was developed from the most relevant and up-to-date existing speed management 

guides, informational resources, and research evidence. There are three main types of content. 

 The first section, an Annotated Bibliography provides a descriptive list of key speed management resources. The Bibliography 

also indicates the primary target audiences who may find the resources most useful. Resources were reviewed as part of the 

project to identify best speed management practices, and to develop the model speed management Action Plan template. 

 The second section describes crash- and speed-reducing countermeasures and the effects that might be expected for 

implementing the listed treatments. The countermeasures included, with potential crash effects or Crash Modification 

Factors (CMFs), are derived from high quality evaluations. Several sources were consulted to develop the list of 

countermeasures with strong evidence of crash or speed-reducing effects. Key among these sources were the Highway 

Safety Manual, the Crash Modification Factors Clearinghouse, and FHWA proven safety countermeasures information. 

Although only measures that have a high quality of evaluation evidence were included in these lists, other measures may also 

have crash-reducing effects, but the evidence is not as conclusive. New knowledge emerges continually, so practitioners are 

encouraged to consult the Crash Modification Factors Clearinghouse and other sources for the most up-to-date information. 

These CMF effect estimates may be used in cost : benefit assessments to help prioritize among alternate countermeasures as 

described in the Action Plan template. 

 The third section provides tip sheets for communications experts and others involved in supporting the speed management 

program and countermeasures through education and awareness efforts. The tip sheets provide guidance on developing a 

locally-tailored communications program. Creating and sustaining an effective speed management program requires the 

commitment and support of diverse stakeholders, including users of the roadways and effective communications can help 

build such support. In addition, safety benefits of specific countermeasures, such as enforcement or new or unfamiliar 

engineering treatments, may be enhanced with an effective communications programs. 
Speed Management Toolkit

2

Annotated Bibliography of Key Speed Management Resources

Table 1. Speed Management Resources - Annotated Bibliography.

Speed Management Resources - Annotated Bibliography

Resource Description Primary Audience

Highway Safety Manual, 1st 

edition. American 

Association of State Highway 

and Transportation Officials: 

Washington, D.C., 2010.

Available at:

highwaysafetymanual.org. 

“The first edition of the [Highway Safety Manual] HSM provides the best 

factual information and tools in a useful form to facilitate roadway 

planning, design, operations, and maintenance decisions based on precise 

consideration of their safety consequences. The primary focus of the HSM is 

the introduction and development of analytical tools for predicting the 

impact of transportation project and program decisions on road safety.

AASHTO’s Highway Safety Manual webpage serves as the official HSM 

website where you can find the most up to date information and new 

developments on the HSM.”

-Engineers

-Program Managers 

Crash Modification Factors 

Clearinghouse. Interactive 

website resource. 

U.S. Department of 

Transportation, Federal 

Highway Administration web 

page. Available at: 

http://www.cmfclearinghous

e.org/.

“This site is funded by the U.S. Department of Transportation Federal 

Highway Administration and maintained by the University of North Carolina 

Highway Safety Research Center. This site is continually updated with the 

latest information on safety or crash effects of countermeasures. “A crash 

modification factor (CMF) is a multiplicative factor used to compute the 

expected number of crashes after implementing a given countermeasure at 

a specific site. The Crash Modification Factors Clearinghouse houses a Webbased database of CMFs along with supporting documentation to help 

transportation engineers identify the most appropriate countermeasure for 

their safety needs. Using this site, you can search to find CMFs” to treat 

identified problems.

-Engineers

-Program Managers
Speed Management Toolkit

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Speed Management Resources - Annotated Bibliography

Resource Description Primary Audience

CMFs in Practice. U.S. DOT, 

Federal Highway 

Administration web page

Available at: 

http://safety.fhwa.dot.gov/t

ools/crf/resources/cmfs/.

“Crash modification factors (CMFs) support a number of safety-related 

activities in the project development process. The CMFs in Practice Series 

includes five separate guides that identify opportunities to consider and 

quantify safety in specific activities, including roadway safety management 

processes, road safety audits, design decisions and exceptions, development 

and analysis of alternatives and value engineering. The series also includes 

reference documents that provide background information on crash 

modification factors and safety performance functions.”

-Engineers

Speed Concepts: 

Informational Guide.

Washington, D.C.: Office of 

Safety, Federal Highway 

Administration, 2009.

Available at: 

http://safety.fhwa.dot.gov/s

peedmgt/ref_mats/fhwasa1

0001/ .

“The objectives of this guide are to:

 -Define common speed-related terminology so that the guide’s contents 

can be clearly conveyed.

 - Explain the differences between designated design speed, inferred design 

speed, operating speed, and posted speed limits.

 - Illustrate perceptions and research conclusions related to the effects of 

speed.

 -Document speed-based technical processes.

 - Summarize State and local government agency roles and actions related 

to traffic speed.

 - Highlight speed management and mitigation measures.”

-Engineers

-Enforcement

-Others

Automated Enforcement for 

Speeding and Red Light 

Running. NCHRP Report 729, 

Washington, D.C.: 

Transportation Research 

Board, 2012.

Available at: 

http://www.trb.org/main/bl

urbs/167757.aspx.

“TRB’s [Transportation Research Board] National Cooperative Highway 

Research Program (NCHRP) Report 729: Automated Enforcement for 

Speeding and Red Light Running includes guidelines designed to help 

transportation agencies start-up and operate automated enforcement 

programs to improve highway safety by reducing speeding and red light 

running.”

-Enforcement

-Program Managers
Speed Management Toolkit

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Speed Management Resources - Annotated Bibliography

Resource Description Primary Audience

Engineering 

Countermeasures for 

Reducing Speeds: A Desktop 

Reference of Potential 

Effectiveness in Reducing 

Speed. FHWA Office of 

Safety website tool, 2014. 

Available at:

http://safety.fhwa.dot.gov/s

peedmgt/ref_mats/eng_cou

nt/2014/reducing_speed.cf

m.

“This chart summarizes studies about engineering countermeasures used to 

manage speeds. Studies where an increase in speed were reported are also 

shown since this information is also relevant in selection of 

countermeasures.”

-Engineers

-Others

Engineering Speed 

Management 

Countermeasures:

A Desktop Reference of 

Potential Effectiveness in 

Reducing Crashes. FHWA 

Office of Safety website tool, 

2014. Available at: 

http://safety.fhwa.dot.gov/s

peedmgt/ref_mats/eng_cou

nt/2014/eng_ctm_crsh_14.p

df

“This chart summarizes studies about the effectiveness of engineering 

countermeasures. Studies where an increase in crashes were reported are 

also shown since this

information is also relevant in selection of countermeasures.”

-Engineers

-Others
Speed Management Toolkit

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Speed Management Resources - Annotated Bibliography

Resource Description Primary Audience

Traffic Calming: State of the 

Practice. Prepared for the 

U.S. Department of 

Transportation, Federal 

Highway Administration, by 

Institute of Transportation 

Engineers, 1999. Available 

at:

http://www.ite.org/traffic/tc

state.asp - tcsop.

“Traffic Calming: State of the Practice is an Informational Report of the 

Institute of Transportation Engineers (ITE) and the Federal Highway 

Administration (FHWA). The information in this document has been 

obtained from the research and experiences of transportation engineering 

and planning professionals. The report was prepared by ITE on behalf of 

FHWA for informational purposes only and does not include 

recommendations on the best course of action or the preferred application 

of the data.”

-Engineers

FHWA Guidance 

Memorandum on 

Consideration and 

Implementation of Proven 

Safety Countermeasures.

Date: July 10, 2008

Available at: 

http://safety.fhwa.dot.gov/p

olicy/memo071008/.

Considerations and Implementation of Proven Safety Countermeasures. -All

FHWA. Speed Management 

Safety.

Available at: 

http://safety.fhwa.dot.gov/s

peedmgt/.

FHWA Speed Management webpages and resources. -Engineers
Speed Management Toolkit

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Speed Management Resources - Annotated Bibliography

Resource Description Primary Audience

Methods and Practices for 

Setting Speed Limits: An 

Informational Report. 

Washington, D.C.: Federal 

Highway Administration, 

Report no. FHWA-SA-12-004.

Available at: 

http://safety.fhwa.dot.gov/s

peedmgt/ref_mats/fhwasa1

2004/.

“This informational report describes four primary practices and 

methodologies that are used in establishing speed limits (engineering 

approach, expert systems, optimization, and injury minimization). It also 

reviews the basic legalities of speed limits and presents several case studies 

for setting speed limits on a variety of roads.”

-Engineers 

-Program Managers

-Policy-Makers

Community Speed 

Reduction and Public 

Health. Informational 

resources and case studies.

Available at: 

http://hria.org/resources/re

ports/community-speedreduction/2013-resourcesspeed-reduction.html.

“Motor vehicle crashes are the leading cause of unintentional injury deaths 

in the United States each year. In 2011, vehicle speed played a role in nearly 

one in three crash deaths, about ninety percent of which took place on nonInterstate roads. High speeds are especially dangerous for pedestrians and 

cyclists, who are disproportionately threatened by even small increases in 

traffic speed, when collisions occur. Poor road design, lack of enforcement, 

and speed limits that are set too high can encourage high speeds. 

Community-wide speed reduction strategies intervene in the built 

environment to slow down motor vehicles and are systematically applied 

within a defined geographic area.”

- See more at: http://hria.org/resources/reports/community-speedreduction/2013-resources-speed-reduction.html - sthash.EqjnT2WZ.dpuf.

-Public Health /

Injury Prevention

-Policymakers
Speed Management Toolkit

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Speed Management Resources - Annotated Bibliography

Resource Description Primary Audience

Interactive Highway Safety 

Design Model (IHSDM). 

Website with description 

and link to the IHSDM

modeling tool.

Available at:

http://www.fhwa.dot.gov/re

search/tfhrc/projects/safety/

comprehensive/ihsdm/.

“IHSDM development is coordinated with two related initiatives: the 

Highway Safety Manual, developed by the Transportation Research Board 

and published by AASHTO; and the SafetyAnalyst, developed by FHWA and 

now available as AASHTOWare.

The Interactive Highway Safety Design Model (IHSDM) is a suite of software 

analysis tools for evaluating safety and operational effects of geometric 

design decisions on highways. IHSDM is a decision-support tool. It provides 

estimates of a highway design's expected safety and operational 

performance and checks existing or proposed highway designs against 

relevant design policy values. IHSDM results support decision making in the 

highway design process. Intended users include highway project managers, 

designers, and traffic and safety reviewers in State and local highway 

agencies and engineering consulting firms.

IHSDM currently includes six evaluation modules (Crash Prediction, Design 

Consistency, Intersection Review, Policy Review, Traffic Analysis, and 

Driver/Vehicle).”

-Engineers

Managing Speed: Review of 

current practice for setting 

and enforcing speed limits.

Transportation Research 

Board, Special Report 254, 

National Research 

Council. Washington, D.C., 

National Academy Press, 

1998.

Available: 

http://www.trb.org/Main/Bl

urbs/152251.aspx.

“Managing Speed: Review of Current Practices for Setting and Enforcing 

Speed Limits reviews practices for setting and enforcing speed limits on all 

types of roads and provides guidance to state and local governments on 

appropriate methods of setting speed limits and related enforcement 

strategies. Following an executive summary, the report is presented in six 

chapters and five appendices.”

-Engineers

-Program Managers

-Enforcement 
Speed Management Toolkit

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Speed Management Resources - Annotated Bibliography

Resource Description Primary Audience

Adding Power to Our Voices: 

A Framing Guide for 

Communicating about 

Injury. National Center for 

Injury Prevention and 

Control: Atlanta, GA: US 

Department of health and 

Human Services, Centers for 

Disease Control and 

Prevention; 2008 (revised 

March 2010). 

Available: 

http://www.cdc.gov/injury/f

raming.

“This guide is designed to help organizations involved in injury and violence 

prevention and response speak with a consistent voice. The framing guide is 

built on the belief that the collective voice of many injury and violence 

professionals across several disciplines is much louder than that of an 

individual or single organization.

This guide incorporates framing theory, message development techniques 

and vehicles for explaining important public health statistics. The 

information and tools provided in this Guide can be used to build messages 

that can be included in press releases, speeches, annual reports, and 

research articles, to help health professionals better communicate with their 

audiences.”

-Communications 

Specialists

Roundabouts: An 

informational guide, Second 

edition. NCHRP Report 672, 

Transportation Research 

Board: Washington, D.C., 

2010.

Available: 

http://onlinepubs.trb.org/on

linepubs/nchrp/nchrp_rpt_6

72.pdf.

“This report updates the FHWA’s Roundabouts: An Informational Guide

based on experience gained in the United States since that guide was 

published in 2000. The report addresses the planning, design, construction, 

maintenance, and operation of roundabouts. It also includes information 

that will be useful in explaining to the public the trade-offs associated with 

roundabouts.”

-Engineers
Speed Management Toolkit

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Speed Management Resources - Annotated Bibliography

Resource Description Primary Audience

Guidance for 

Implementation of the 

AASHTO Strategic Highway 

Safety Plan. Volume 21: 

Safety Data and Analysis in 

Developing Emphasis Area 

Plans. Washington, DC: 

NCHRP, Transportation 

Research Board, 2008.

Available: 

onlinepubs.trb.org/Onlinepu

bs/nchrp/nchrp_rpt_500v21.

pdf.

“This guide specifically addresses highway safety data, an emphasis area 

under the management category in AASHTO’s SHAP, and was developed to 

aid highway safety analysts in using the other implementation guides to 

make decisions about how to appropriately allocate safety funds to get the 

best results. Section I introduces a three-stage process for identifying a 

target emphasis area, setting an appropriate injury (and fatality) reduction 

goal, and defining the treatments that will allow the jurisdiction to reach 

that goal.” Section II describes the types of data necessary; Section III lays 

out the details of the three-stage process; and the remaining sections 

provide a detailed description of the specific applications of the process and 

procedures for roadway segments, junctions, special road users, illegal 

driver actions, unsafe driver actions, work zones, and EMS services.”

-Program Managers

-Data Analysts

Guidance for 

Implementation of the 

AASHTO Strategic Highway 

Safety Plan. Volume 23: A 

Guide for Reducing 

Speeding-Related Crashes. 

Washington, DC: NCHRP,

Transportation Research 

Board, 2009. 

Available: 

onlinepubs.trb.org/onlinepu

bs/nchrp/nchrp_rpt_500v23.

pdf. 

Note: This guide, one of a series of 23 such guides in the NCHRP Report 500 

series, describes essential processes and a speed management program 

planning framework, as well as specific strategies and countermeasures, to 

assist with meeting Strategic Highway Safety Plan objectives. 

“One of the hallmarks of the AASHTO Strategic Highway Safety Plan process 

is to approach safety problems in a comprehensive manner. The range of 

strategies available in the guides cover various aspects of the road user, the 

highway, the vehicle, the environment, and the management system. The 

guides strongly encourage the user to develop a program to tackle a 

particular emphasis area from each of these perspectives in a coordinated 

manner.”

-All Road Safety 

Practitioners

-Program Managers
Speed Management Toolkit

10

Speed Management Resources - Annotated Bibliography

Resource Description Primary Audience

Countermeasures that 

Work, 7

th ed. Department of 

Transportation, National 

Highway Traffic Safety 

Administration, 2013. 

Available at: 

www.nhtsa.gov/staticfiles/nt

i/pdf/811727.pdf.

“The National Highway Traffic Safety Administration has released the latest 

edition of its report that explores major highway safety strategies and 

countermeasures that are relevant to State Highway Safety Offices; 

summarizes their use, effectiveness, costs, and implementation time; and 

provides references to safety research summaries and individual studies.”

-Enforcement

-Educators

-Communications

Specialists

Uniform Guidelines for State 

Highway Safety Programs. 

Highway Safety Program 

Guidelines No. 19. National 

Highway Traffic Safety 

Administration, 2006.

Available:

http://www.nhtsa.gov/nhtsa

/whatsup/tea21/tea21progr

ams/402guide.html#g19.

The Speed Control Guidelines (no. 19) is one of 21 sets of uniform program 

guidelines for state highway safety programs developed for TEA21.

“Introduction: Each State, in cooperation with its political subdivisions, 

should have, as part of a comprehensive highway safety program, an 

effective speed control program that encourages its citizens to voluntarily 

comply with speed limits. The program should stress systematic and rational 

establishment of speed limits, a law enforcement commitment to 

controlling speed on all public roads, a commitment to utilize both 

traditional methods and state-of-the art equipment in setting and enforcing 

speed limits, and a strong public information and education program aimed 

at increasing driver compliance with speed limits.”

-Program Managers

-Enforcement

-Communications

Specialists
Speed Management Toolkit

11

Speed Management Resources - Annotated Bibliography

Resource Description Primary Audience

Effectiveness of Behavioral 

Highway Safety 

Countermeasures, NCHRP 

Report 622.Washington, DC: 

Transportation Research 

Board, 2008. 

Available: 

http://www.nap.edu/openb

ook.php?record_id=14195.

"The goal of this project is to assist states in selecting programs, projects, 

and activities that have the greatest potential for the reduction of highway 

death and injury. The specific objectives are as follows:

Produce a manual for application of behavioral highway safety 

countermeasures and develop a frame-work and guidance for estimating 

the costs and benefits of emerging, experimental, untried, or unproven

behavioral highway safety countermeasures."

-Enforcement

-Communications

Specialists 

-Program Managers
Speed Management Toolkit

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Speed Management Resources - Annotated Bibliography

Resource Description Primary Audience

Road Safety Audit resources 

on FHWA website: 

http://safety.fhwa.dot.gov/r

sa/.

FHWA Road Safety Audit 

Guidelines. Available: 

http://safety.fhwa.dot.gov/

rsa/guidelines/.

Pedestrian Road Safety 

Audit Guidelines and 

Prompt Lists. Highway 

Administration.

Available: 

http://safety.fhwa.dot.gov/p

ed_bike/tools_solve/ped_rsa

/.

Bicycle Road Safety Audit 

Guidelines and Prompt Lists.

Available: 

http://safety.fhwa.dot.gov/p

ed_bike/tools_solve/fhwasa

12018/.

“A Road Safety Audit (RSA) is the formal safety performance examination of 

an existing or future road or intersection by an independent, 

multidisciplinary team. It qualitatively estimates and reports on potential 

road safety issues and identifies opportunities for improvements in safety 

for all road users. The FHWA works with State and local jurisdictions and 

Tribal Governments to integrate RSAs into the project development process 

for new roads and intersections, and also encourages RSAs on existing roads 

and intersections...

The aim of an RSA is to answer the following questions:

 -What elements of the road may present a safety concern: to what extent, 

to which road users, and under what circumstances?

 -What opportunities exist to eliminate or mitigate identified safety 

concerns?

Public agencies with a desire to improve the overall safety performance of 

roadways under their jurisdiction should be excited about the concept of 

RSAs. Road safety audits can be used in any phase of project development 

from planning and preliminary engineering, design and construction. RSAs 

can also be used on any sized project from minor intersection and roadway 

retrofits to mega-projects.”

Note: The pedestrian and bicycle road safety audit guidelines provide 

supplemental information focusing on safety and roadway issues 

particularly affecting those users. 

-Engineers

-Planners

-Law Enforcement

-Other Road Safety 

Stakeholders
Speed Management Toolkit

13

Speed Management Resources - Annotated Bibliography

Resource Description Primary Audience

Safety Analyst.

AASHTOware. Network 

screening analysis tool.

Available: 

http://www.safetyanalyst.or

g/.

“Synopsis: SafetyAnalyst incorporates state-of-the-art safety management 

approaches into computerized analytical tools for guiding the decisionmaking process to identify safety improvement needs and develop a system

wide program of site-specific improvement projects. SafetyAnalyst has a 

strong basis in cost-effectiveness analysis; thus, SafetyAnalyst has an 

important role in ensuring that highway agencies get the greatest possible 

safety benefit from each dollar spent in the name of safety.

SafetyAnalyst was developed as a cooperative effort by FHWA and 

participating state and local agencies. AASHTO manages distribution, 

technical support, maintenance, and enhancement of SafetyAnalyst as a 

licensed AASHTOWare product.”

-Engineers

Speed Management: Road 

Safety Manual for Decisionmakers and Practitioners.

Geneva: Global Road Safety 

Partnership, 2008. Available

at: 

http://www.who.int/roadsaf

ety/projects/manuals/speed

_manual/en/.

“This speed management manual proposes simple, effective and low-cost 

solutions to excessive and inappropriate speed that can be implemented on 

a national or local level. It targets governments, non-governmental 

organizations and road safety practitioners, particularly those in low- and 

middle-income countries. The manual is based on a modular structure that 

provides evidence, examples, case studies and practical steps on how to 

manage vehicle speed.”

-All Safety 

Stakeholders

-Program Managers

-Policymakers

U.S. DOT, NHTSA Branding 

website. Accessible at: 

http://www.trafficsafetymar

keting.gov/TOOLS/Branding.

General traffic safety marketing guidance. -Communications

Specialists
Speed Management Toolkit

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Speed Management Resources - Annotated Bibliography

Resource Description Primary Audience

Speed Enforcement Camera 

Systems: Operational 

Guidelines. Washington, DC: 

U.S. Department of 

Transportation, National 

Highway Traffic Safety 

Administration and Federal 

Highway Administration, 

2008. 

Available at: 

http://ntl.bts.gov/lib/30000/

30100/30166/810916.pdf.

“The ASE guidelines are intended to serve program managers, 

administrators, law enforcement, traffic engineers, program evaluators, and 

other individuals responsible for the strategic vision and daily operations of 

the program. The guidelines are written from a U.S. perspective and 

emphasize U.S. contexts and best practices. However, they are also drawn 

from the experiences of exemplary programs internationally. Though 

international differences in law, history, and culture might influence best 

practices for ASE, the majority of these guidelines are relevant to ASE 

programs worldwide.”

-Enforcement

-Engineering

-Program Managers

USLimits2. FHWA. A Tool to 

Aid Practitioners in 

Determining Appropriate 

Speed Limit 

Recommendations. 

Tool available at: 

http://safety.fhwa.dot.gov/u

slimits/

“USLIMITS is a web based tool designed to help practitioners set reasonable, 

safe, and consistent speed limits for specific segments of roads. USLIMITS is 

applicable to all types of roads ranging from rural local roads and 

residential streets to urban freeways.

User-friendly, logical, and objective, USLIMITS2 is of particular benefit to 

local communities and agencies without ready access to engineers 

experienced in conducting speed studies for setting appropriate speed 

limits. For experienced engineers, USLIMITS2 can provide an objective 

second opinion and increase confidence in speed limit setting decisions.”

A related report documenting research for USLimits, 1st ed.: 

Expert System for Recommending Speed Limits in Speed Zones: Final Report.

National Cooperative Highway Research Program, Transportation Research Board. 

Available at: 

onlinepubs.trb.org/onlinepubs/trbnet/acl/NCHRP%200367_FinalReport.pdf. 

-Engineers

-Others responsible 

for setting speed 

limits
Speed Management Toolkit

15

Speed Management Countermeasures

Countermeasures included in this Resource are ones with well-documented safety or speed-reducing effects. The countermeasures 

with expected crash modifying effects (Crash Modifying Factors or CMFs) that were included in the Highway Safety Manual 

(AASHTO, 2010) or that are derived from high quality studies that have since been added to the CMF Clearinghouse are included.

(See more information on these resources in the bibliography.) In addition, some measures with speed-reducing or calming effects 

but (as of the time this document was prepared) unproven crash-reducing effects, are also included, since measures known to 

reduce speeds are also expected to reduce fatal and injury crashes. In particular, geometric measures that by their design limit travel 

speeds are expected to lower speeds where vehicles are traveling above those design speeds. More information on using these 

estimates of speed reduction to determine expected crash benefits is provided below.

Table 2 provides an overview of the countermeasures identified to reduce crashes, and/or control travel speed by design. Other 

types of treatments that have been reported to reduce travel speeds in multiple studies at multiple locations are also included for 

consideration. Other measures may also reduce travel speeds and crashes in some situations, but the evidence is less conclusive.

Below Table 2, the listed countermeasures are grouped into additional tables containing more details about the expected crash or 

speed effects of these treatments. Separate tables are provided for measures with expected crash reductions (crash modification 

effects) and measures with expected speed reductions as follows:

 Road Design and Traffic Calming countermeasures.

 Potential crash effects (Table 3).

 Potential speed reduction effects (Table 4).

 Pavement Treatments, Markings, and Signs.

 Potential crash effects (Table 5).

 Potential speed reduction effects (Table 6).

 Traffic Speed Management and Operations measures.

 Potential crash effects (Table 7).

 Enforcement and Publicity measures.

 Potential crash effects (Table 8).

Two other tables are included (Table 9 and Table 10) that show what the crash effects might be for countermeasures that reduce 

travel speeds (Tables 4 and 6, and FHWA’s Engineering Countermeasures for Reducing Speeds), but measured crash effects are 

unavailable.
Speed Management Toolkit

16

Table 2 shows the area and location types where the countermeasure is most typically applied. The two right-most columns under 

“Documented Effects” indicate whether research has found crash-reducing or speed-reducing effects of the treatment, or both.

Table 2. Matrix of Speeding-related Crash Countermeasures.

Matrix of Speeding-related Crash Countermeasures

Area Type Location Type Documented Effects

Countermeasure Name Urban Suburban Rural Intersection

Section/ 

corridor Curve Crash Reducing

1

Speed 

Reducing

Design and Traffic Calming

Area-wide Traffic Calming X X X X X X X

Chicanes X X X X X

Full Closure X X X

Gateway Treatment X X X X

Half Closure X X X

Lateral Shift X X X X X

Mini Traffic Circle X X X X X X

Realigned Skewed Intersection X X X X X X

Reduce Lane Width on Intersection Approaches using 

longitudinal rumble strips and painted median X X X X

Road Diet X X X X X

Roundabout X X X X Pos.2X X

Speed Cushions X X X X X

Speed Humps X X X X X

 

1

Crash-based evidence may be unavailable for some measures with documented speed-reducing effects. Estimates of speed reduction may be used in 

conjunction with Highway Safety Manual estimates of crash modification effects for changes in average operating speed to generate crash modification 

estimates for speed-reducing treatments.

2 May also improve flow and average mobility along a corridor.
Speed Management Toolkit

17

Matrix of Speeding-related Crash Countermeasures

Area Type Location Type Documented Effects

Countermeasure Name Urban Suburban Rural Intersection

Section/ 

corridor Curve Crash Reducing

1

Speed 

Reducing

Design and Traffic Calming

Speed Tables X X X X X

Traffic Calming (varied) X X X X X X X

Pavement Treatments, Markings, Signs, and Signals

Enhanced Curve Delineation X X X

Optical Speed bars / Converging Chevrons X X X X X X Possibly

Transverse (in lane) Rumble Strips for Speed Calming Pos.3Pos. X X X X

Speed Management and Traffic Operations Measures 

Lower Speed Limits on Expressway X X X X X

Protected-only Left Turn Signal Phasing (high-speed 

intersections) X X

Signal Coordination along a Corridor X X X X X

Variable Speed Limits on Expressway 4X X X X

Enforcement and Publicity

Automated Section Speed Enforcement

Mobile Speed Camera Enforcement X X X X

Fixed Speed Camera Enforcement X X X X

Publicity of Automated Speed Enforcement Cameras X X X

Speed Display / Feedback Devices X X X X X X

5

 

3 May be used in urban / suburban areas, but there are noise considerations in developed areas.

4

In testing phase in U.S. but promising speed and crash reductions have been documented when limits are lowered.

5

Effective where and while in place. Effects enhanced with visible law enforcement presence. May not be effective in some areas. 
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Users should consider that combinations of multiple countermeasures might be appropriate and generate larger crash reductions 

than any one measure. Other types of countermeasures may provide mitigation or reduce crash types that frequently involve 

speeding, but are not included in this Resource. Such measures as improving pavement friction, providing shoulder and centerline 

rumble strips, and providing roadside barriers may reduce some types of crashes that are potentially associated with speeding, but 

are unlikely to reduce travel speeds.

Using the Tables of Crash Modification Factor (CMF) Estimates 

In each of the tables with crash modification estimates below, the expected effects on crashes of the listed countermeasures are 

shown in the “CMFs” column. CMFs (or crash modification factors) show the expected effects (with standard errors when available) 

of the different treatments compared to if no treatment were applied. These estimates may be used to help perform cost : benefit 

analysis of alternate potential countermeasures as described in the Action Plan Template document and other sources. 

Countermeasures with CMFs less than 1 are expected to have a crash-reducing effect. For example, a CMF of 0.7 is expected to yield 

a crash rate of 0.7 times the expected crash rate if no treatment is applied, or a 30 percent crash reduction, controlling for traffic 

volume and other trends. Statistically significant CMFs are shown with asterisks. 

A few non-significant CMF effects are included that indicate potential safety improvement, but uncertainty of the estimate means 

the CMF may be no different than 1 (within 90 or 95% confidence limits). The standard error estimates provide an indication of the 

variability and reliability of the estimate. Small standard errors (s.e.) that are much less than the estimated CMF indicate more 

robust and reliable estimates. Some non-significant effects or negative treatment effects were also included in the tables for more 

complete disclosure about the overall potential effects of a treatment. Treatments may sometimes have beneficial effects on certain 

crash types or severities but no effect or negative effects on other types or severities. The potential user should understand these 

potential trade-offs to understand how best to apply the treatment. 
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The CMF star ratings provide another indication of the quality or reliability of the estimate, as provided by the expert reviewers for 

the CMF Clearinghouse. A five point star-rating system (highest quality) was developed using five measures of study quality.6 An 

“HSM” in the CMF star rating column indicates that the estimate is from the Highway Safety Manual. 

The area and location types, and types of crashes covered by the CMF estimate, are those that were included in the study and may 

not be generalizable to other conditions. Other disaggregate effect measures may also be available from some studies. The sources 

of the estimates are provided in footnoted references. If specific estimates are unavailable for the circumstances for which 

treatment is needed, the estimate for the most similar circumstances may be used, but additional uncertainty or caution may be 

warranted. In addition, locally-calibrated CMFs should be used, if available, as estimates derived from other States/areas may need 

adjustment to reflect differences in expected outcomes.

The CMF estimates (or locally-calibrated CMFs) may be used to help determine the expected economic benefits or cost-effectiveness

of each treatment. As per the Action Plan, each corridor or location must undergo further diagnosis to determine the most 

appropriate treatment or combination of treatments among alternates available.

Using the Tables of Potential Speed Reduction Effects

Traffic calming measures with speed limiting designs (primarily measures that require a vertical or horizontal shift in the travel way) 

are included in Table 4. Other traffic calming measures that have been reported to reduce travel speeds in multiple studies at 

multiple locations are also included in Table 4 and Table 6.

The speed reduction estimates in Table 4 (Traffic Calming Measures) and Table 6 (Pavement Treatments, Markings and Signs) are 

reproduced from the 2009 version of Engineering Countermeasures for Reducing Speeds. Note that this resource was updated in 

2014, and the updated resource is available on FHWA’s speed management web pages. This and a companion resource on the crash 

effects of speed-related countermeasures are both referenced in Table 1. More information about the reported changes in speed 

 

6

CMF Clearinghouse. The star quality ratings are based assessments of study design, sample size, standard error, potential bias, and data source. For more 

information see the Clearinghouse website at http://www.cmfclearinghouse.org/sqr.cfm
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and references to the original studies are available in the Engineering Countermeasures resource. Note that different studies may 

have measured speeds using different methods. For example, not all may have measured change in free-flow operating speeds, so 

caution or review of the original studies is suggested. The resources (both 2009 and 2014) also include additional countermeasures 

reported in some instances to reduce travel speeds, but effects may not be consistent. Similar to CMF estimates with larger standard 

errors, larger standard deviations suggest that speed results obtained may vary to a greater degree compared to measures with 

lower standard deviations. Again, combinations of treatments may be needed to achieve desired crash/speed reductions.

In the case of measures for which there are estimates of speed change, but as yet no measured crash effects, estimates of potential 

crash effects can be obtained by using expected crash effects for changes in average travel speed. As mentioned earlier, CMFs from 

Table 9 and Table 10, which were adapted from the Highway Safety Manual, may be used to estimate fatal and injury crash effects 

for countermeasures that reduce average travel speed. 

Table 3 follows with crash effect estimates for design and traffic calming treatments.
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Table 3. Potential Crash Effects (CMFs) for Design and Traffic Calming Treatments.

CMFs for Design and Traffic Calming Treatments

Countermeasure Description Area Type Road / Intersection 

Type Traffic Volume Crash Type

Crash 

Injury 

Severity 

CMF 7

(std. error)

CMF 

Star

Rating 

Traffic Calming 8Area/corridorwide traffic 

calming 

Urban All Up to 30,000 All Serious, 

Minor 

Injury

0.89**

(0.05)

5

Traffic Calming 8Area/corridorwide traffic 

calming

Urban Local Not specified All Serious, 

Minor 

Injury

0.82

(0.12)

3

Traffic Calming 8Area/corridorwide traffic 

calming

Urban Major, Minor Collector 

(2+ lanes)

5000 - 30,000 All Serious, 

Minor 

Injury

0.94

(0.06)

3

Realign Skewed 

Intersection 9

Realign 

skewed 

angle(s) of 

intersection 

approach(es)

Rural Unsignalized, 3-leg 

intersection of 2-

lane highways 

(minor road stopcontrolled)

Not specified All All CMF = 

e(0.0040 x

SKEW angle) 10

Equations 

cannot 

be 

rated

 

7

In this and each subsequent table of CMFs, ** (two asterisks) next to the CMF estimate indicates effects significant at the 0.05 level (95% confidence 

interval). 

In this and each subsequent table of CMFs, * (one asterisk) next to the CMF estimate indicates effects significant at the 0.10 level (90% confidence interval). 

No stars indicates that the effects reported were not statistically significant, or significance could not be determined.

8

Source: Elvik, R. and Vaa, T., (2004). Handbook of Road Safety Measures. Oxford, United Kingdom: Elsevier.

9

Sources: AASHTO (2010). Highway Safety Manual, 1st ed. Washington, DC: American Association of State Highway and Transportation Officials. [There are 

mistakes in equations for multilane roads in the HSM; also see: Lord et al., Methodology for Estimating the Safety Performance of Multilane Rural Highways.

National Cooperative Highway Research Program 17-29 Project, Washington, DC: NCHRP, for the original equations.]

10 The base condition for this CMF is an intersection without any skew (i.e., all the intersection angles are 90 degrees). If converting from a skewed intersection 

to an intersection without skew (all right angles), the inverse of the CMF (i.e., 1/CMF) should be used. If converting from an intersection with more skew to 
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CMFs for Design and Traffic Calming Treatments

Countermeasure Description Area Type Road / Intersection 

Type Traffic Volume Crash Type

Crash 

Injury 

Severity 

CMF 7

(std. error)

CMF 

Star

Rating 

Realign Skewed 

Intersection 9

Realign 

skewed 

angle(s) of 

intersection 

approach(es)

Rural Unsignalized 4-leg 

intersection of 2-

lane highways 

(minor road stopcontrolled)

Not specified All All CMF = 

e(0.0054 x

SKEW angle) 10

Cannot 

be 

rated

Realign Skewed 

Intersection 9

Realign 

skewed 

angle(s) of 

intersection 

approach(es)

Rural Unsignalized 3-leg 

intersection of 

multi-lane highways 

(minor road stopcontrolled)

Not specified All All CMF = 0.016 x 

SKEW/(098 + 

0.016 x SKEW

angle) + 1.0 10

Cannot 

be 

rated

Realign Skewed 

Intersection 9

Realign 

skewed 

angle(s) of 

intersection 

approach(es)

Rural Unsignalized 4-leg 

intersection of 

multi-lane highways 

(minor road stopcontrolled)

Not specified All All CMF = (0.053 x 

SKEW)/ (1.43 + 

0.053 x SKEW

angle) + 1.0 10

Cannot 

be 

rated

 

one with less skew, use the difference between the CMFs for the estimated crash effects of the different skew angles. For more information see the Highway 

Safety Manual or http://safety.fhwa.dot.gov/intersection/resources/intsafestratbro/ub16_intersection_skew.pdf.
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CMFs for Design and Traffic Calming Treatments

Countermeasure Description Area Type Road / Intersection 

Type Traffic Volume Crash Type

Crash 

Injury 

Severity 

CMF 7

(std. error)

CMF 

Star

Rating 

Reduce Lane 

Width -

Intersection 

Approach 11

Reduce lane 

width using 

longitudinal 

rumble strips on 

both edge lines 

and painted 

median

Rural Major (high speed) 

road approach of 2-

lane, 2-way 

roadways with 2-

way STOP-control, 

3-leg, 4-leg.

Not specified All All 0.69

(n/a)

2

12

Reduce Lane 

Width -

Intersection 

Approach 11

Reduce lane 

width using 

longitudinal 

rumble strips on 

both edge lines 

and painted 

median

Rural Major (high speed) 

road approach of 2-

lane, 2-way 

roadways with 2-

way STOP-control, 

3-leg, 4-leg.

Not specified All Fatal, 

Serious, 

Minor 

Injury

0.8

(n/a)

2

 

11 Source: Hughes, W., Jagannathan, R., and Gross, F. (2008). Two Low Cost Safety Concepts for Two Way Stop Controlled, Rural Intersections on High Speed 

Two Lane, Two Way Roadways, (Report No. FHWA-HRT-08-063), Washington, DC: Federal Highway Administration. Available at: 

http://www.fhwa.dot.gov/publications/research/safety/10047/index.cfm.

12 Note increase in rear-end crashes. Although the CMF estimate receives only a fair rating (2 stars) due to a small sample size, a preliminary study observed 

that operating speeds at the treatment sites decreased by an average of 4.5 mph for all vehicles, and by 4.8 mph for trucks. These speed reductions support 

crash reduction effectiveness. 
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CMFs for Design and Traffic Calming Treatments

Countermeasure Description Area Type Road / Intersection 

Type Traffic Volume Crash Type

Crash 

Injury 

Severity 

CMF 7

(std. error)

CMF 

Star

Rating 

Reduce Lane 

Width -

Intersection 

Approach 11

Reduce lane 

width using 

longitudinal 

rumble strips on 

both edge lines 

and painted 

median

Rural Major (high speed) 

road approach of 2-

lane, 2-way 

roadways with 2-

way STOP-control, 

3-leg, 4-leg.

Not specified Angle All 0.58

(n/a)

2

Reduce Lane 

Width -

Intersection 

Approach 11

Reduce lane 

width using 

longitudinal 

rumble strips on 

both edge lines 

and painted 

median

Rural Major (high speed) 

road approach of 2-

lane, 2-way 

roadways with 2-

way STOP-control, 

3-leg, 4-leg.

Not specified Rear-end All 1.54

(n/a)

2
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CMFs for Design and Traffic Calming Treatments

Countermeasure Description Area Type Road / Intersection 

Type Traffic Volume Crash Type

Crash 

Injury 

Severity 

CMF 7

(std. error)

CMF 

Star

Rating 

Road Diet 13 Convert 4-lane 

undivided road 

to 2-lanes plus 

turning lane)

Urban & 

Suburban

Minor Arterial and 

Highway routes

4,000 - 17,000 All All 0.71**

(0.02)

5

Road Diet 13 Convert 4-lane 

undivided road 

to 2-lanes plus 

turning lane)

Large 

Suburban 

area

Minor Arterial 6000 to 17,000 All All 0.81**

(.03)

4

Road Diet 13 Convert 4-lane 

undivided road 

to 2-lanes plus 

turning lane)

Small 

Urban

Highway routes 4000 to 14,000 All All 0.53**

(0.01)

4

Roundabout 14,

15

Convert twoway 

stopcontrolled 

intersection to 

roundabout

All All (1- or 2-lane) Not specified All All 0.56**

(0.04)

5

 

13 Source: NCHRP, (2008). Crash Reduction Factors for Traffic Engineering and ITS Improvements, NCHRP Report 617, Washington, D.C.: National Cooperative 

Highway Research Program, Transportation Research Board. Available at: http://onlinepubs.trb.org/onlinepubs/nchrp/nchrp_rpt_617.pdf.

14 Source: NCHRP (2007). Applying Roundabouts in the United States, NCHRP Report 572, Washington, D.C.: National Cooperative Highway Research Program, 

Transportation Research Board.

15 With the exception of all-way stop control conversions (where no significant change in crashes), roundabouts have provided significant safety benefits in 

urban, suburban and rural environments for both signal-control and stop-controlled conversions (NCHRP 572). Injury /more severe crashes are especially 
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CMFs for Design and Traffic Calming Treatments

Countermeasure Description Area Type Road / Intersection 

Type Traffic Volume Crash Type

Crash 

Injury 

Severity 

CMF 7

(std. error)

CMF 

Star

Rating 

Roundabout 14 Convert twoway 

stopcontrolled 

intersection to 

roundabout

All All (1- or 2-lane) Not specified All Injury 0.18**

(0.03)

5

Roundabout 14 Convert twoway 

stopcontrolled 

intersection to 

roundabout

Rural 1-lane Not specified All All 0.29** 

(0.04)

5

Roundabout 14 Convert twoway 

stopcontrolled 

intersection to 

roundabout

Rural 1-lane Not specified All Injury 0.13** 

(0.03)

5

 

reduced. Safety benefits are highest for single-lane roundabouts. Consider pedestrian (including sight-impaired) and bicyclist needs at entry/crossings and 

especially exits where yielding by motorists was lower. Two-lane entry legs are also more difficult for pedestrians to cross than one-lane entry legs. See 

http://safety.fhwa.dot.gov/intersection/resources/fhwasa10005/brief_14.cfm
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CMFs for Design and Traffic Calming Treatments

Countermeasure Description Area Type Road / Intersection 

Type Traffic Volume Crash Type

Crash 

Injury 

Severity 

CMF 7

(std. error)

CMF 

Star

Rating 

Roundabout 14 Convert twoway 

stopcontrolled 

intersection to 

roundabout

Suburban All 

(1- or2-lane)

Not specified All All 0.68**

(0.07)

4

Roundabout 14 Convert twoway 

stopcontrolled 

intersection to 

roundabout

Suburban All 

(1- or2-lane)

Not specified All Injury 0.29**

(0.08)

4

Roundabout 14 Convert twoway 

stopcontrolled 

intersection to 

roundabout

Suburban 1-lane Not specified All All 0.22**

(0.06)

4

Roundabout 14 Convert twoway 

stopcontrolled 

intersection to 

roundabout

Suburban 1-lane Not specified All Injury 0.22**

(0.10)

4

Roundabout 14 Convert twoway 

stopcontrolled 

intersection to 

roundabout

Suburban 2-lane Not specified All All 0.81**

(0.09)

3
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CMFs for Design and Traffic Calming Treatments

Countermeasure Description Area Type Road / Intersection 

Type Traffic Volume Crash Type

Crash 

Injury 

Severity 

CMF 7

(std. error)

CMF 

Star

Rating 

Roundabout 14 Convert twoway 

stopcontrolled 

intersection to 

roundabout

Suburban 2-lane Not specified All Injury 0.32**

(0.12)

4

Roundabout 16 Convert twoway 

stopcontrolled 

intersection to 

roundabout

Urban All

(1- or 2-lane)

Not specified All All 0.71**

(0.09)

4

Roundabout 16 Convert twoway 

stopcontrolled 

intersection to 

roundabout

Urban All

(1- or 2-lane)

Not specified All Injury 0.19**

(0.08)

4

 

16 Source: NCHRP (2007). Applying Roundabouts in the United States, NCHRP Report 572, Washington, D.C.: National Cooperative Highway Research Program, 

Transportation Research Board.
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CMFs for Design and Traffic Calming Treatments

Countermeasure Description Area Type Road / Intersection 

Type Traffic Volume Crash Type

Crash 

Injury 

Severity 

CMF 7

(std. error)

CMF 

Star

Rating 

Roundabout 16 Convert twoway 

stopcontrolled 

intersection to 

roundabout

Urban 1-lane Not specified All All 0.61**

(0.10)

4

Roundabout 16 Convert twoway 

stopcontrolled 

intersection to 

roundabout

Urban 1-lane Not specified All Injury 0.22**

(0.10)

4

Roundabout 16 Convert twoway 

stopcontrolled 

intersection to 

roundabout

Urban 2-lane Not specified All All 0.88

(0.17)

3

Roundabout 16 Convert twoway 

stopcontrolled 

intersection to 

roundabout

Urban 2-lane Not specified All Injury too few to 

estimate
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CMFs for Design and Traffic Calming Treatments

Countermeasure Description Area Type Road / Intersection 

Type Traffic Volume Crash Type

Crash 

Injury 

Severity 

CMF 7

(std. error)

CMF 

Star

Rating 

Roundabout 17 Convert 

signalized 

intersection to 

roundabout

Urban / 

Suburban

1-lane 5,322-43,123 total 

intersection

All All 0.735**

(0.086)

3

Roundabout 17 Convert 

signalized 

intersection to 

roundabout

Urban / 

Suburban

1-lane 5,322-43,123 total 

intersection

All Fatal, 

Serious, 

Minor 

Injury 

0.451**

(0.115)

3

Roundabout 17 Convert 

signalized 

intersection to 

roundabout

Suburban 1-2-lane 5,322-43,123 total 

intersection

All All 0.576**

(0.053)

4

Roundabout 17 Convert 

signalized 

intersection to 

roundabout

Suburban 1-2-lane 5,322-43,123 total 

intersection

All Fatal, 

Serious, 

Minor 

Injury

0.259**

(0.066)

4

 

17 Source: Srinivasan, R., Baek, J., Smith, S., Sundstrom, C., Carter, D., Lyon, C., Persaud, B., Gross, F., Eccles, K., Hamidi, A., and Lefler, N. (2011). Evaluation of 

Safety Strategies at Signalized Intersections, NCHRP Report 705, Washington, DC.: Transportation Research Board.
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CMFs for Design and Traffic Calming Treatments

Countermeasure Description Area Type Road / Intersection 

Type Traffic Volume Crash Type

Crash 

Injury 

Severity 

CMF 7

(std. error)

CMF 

Star

Rating 

Roundabout 18 Convert 

signalized 

intersection to 

roundabout

Urban 1-2-lane 5,322-43,123 

total intersection

All All 1.150

(0.093)

3

Roundabout 18 Convert 

signalized 

intersection to 

roundabout

Urban 1-2-lane 5,322-43,123 

total intersection

All Fatal, 

Serious, 

Minor 

Injury

0.445**

(0.100)

4

Roundabout 18 Convert 

signalized 

intersection to 

roundabout

Suburban 

and Urban

1-2-lane; 3 leg 

intersection

5,322-43,123 

total intersection

All All 1.066 

(0.163)

3

Roundabout 18 Convert 

signalized 

intersection to 

roundabout

Suburban 

and Urban

1-2-lanes; 3 leg 

intersection

5,322-43,123 

total intersection

All Fatal, 

Serious, 

Minor 

Injury

0.370**

(0.172)

3

Roundabout 18 Convert 

signalized 

intersection to 

roundabout

Suburban 

and Urban

1-2-lane; 4 leg 

intersection

5,322-43,123 

total intersection

All All 0.759**

(0.052)

4

 

18 Source: Srinivasan, R., Baek, J., Smith, S., Sundstrom, C., Carter, D., Lyon, C., Persaud, B., Gross, F., Eccles, K., Hamidi, A., and Lefler, N. (2011). Evaluation of 

Safety Strategies at Signalized Intersections, NCHRP Report 705, Washington, DC.: Transportation Research Board.
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CMFs for Design and Traffic Calming Treatments

Countermeasure Description Area Type Road / Intersection 

Type Traffic Volume Crash Type

Crash 

Injury 

Severity 

CMF 7

(std. error)

CMF 

Star

Rating 

Roundabout 18 Convert 

signalized 

intersection to 

roundabout

Urban / 

Suburban 

1-2-lane; 4 leg 

intersection

5,322-43,123 

total intersection

All Injury and 

Fatal

0.338**

(0.061)

3

Roundabout 18 Convert 

signalized 

intersection to 

roundabout

Urban / 

Suburban

2-lane; 3-4 leg 5,322-43,123 

total intersection

All All 0.809**

(0.061)

4

Roundabout 18 Convert 

signalized 

intersection to 

roundabout

Urban / 

Suburban

2-lane; 3-4 leg 5,322-43,123 

total intersection

All Fatal, 

Serious, 

Minor 

Injury 

0.288**

(0.065)

4

Speed Humps 19 Rounded, raised 

area 

(3 - 4” high 

spanning 12 - 14 

feet in length)

Urban / 

Suburban

Local 2-lane roads Not specified All Serious, 

Minor 

Injury

0.6**

(0.16)

4

Table 4 shows potential speed reductions, based on prior studies, which might be obtained with traffic calming measures. There 

may be significant variability in the speed reduction effect percentages actually obtained, as shown by higher standard deviations in 

the average results. Results may vary by site, or by prior speeds or other conditions. More information is available in the source 

document and original studies. Estimates of speed effects can be used to estimate crash effects by consulting Tables 9 and 10. 

 

19 Source: Elvik, R. and Vaa, T. (2004). Handbook of Road Safety Measures. Oxford, United Kingdom: Elsevier.
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Table 4. Potential Speed Reductions for Design and Traffic Calming Measures.

20

Potential Speed Reductions for Design and Traffic Calming Measures

Countermeasure Description Area Type Road Type Traffic Volume

85th Percentile 

Speed 

Reduction

(std. deviation)

Chicanes Curb extensions that alternate from 

one side of the street to the other, 

forming S-shaped curves. 

Urban Not specified 1,380 - 3,200 16%

(4%)

Chicanes Curb extensions that alternate from 

one side of the street to the other, 

forming S-shaped curves.

Not specified Not specified 1,380 - 1,965 29%

(8%)

Full Closure Physical street closure resulting in a 

dead end

Urban Not specified

(typically 

local/residential)

Not specified 17%

(3%)

Gateway Treatment Combined use of signs, monuments, 

landscaping, and potentially other 

traffic calming treatments at 

entrance to a neighborhood or 

community. 

Rural 

(transition 

area

Main Not specified 5%

(4%)

 

20 Source for speed reduction estimates in this table: Engineering Countermeasures for Reducing Speeds (2009): A Desktop Reference of Potential Effectiveness 

was used as the primary source for the speed change estimates, which were reported for 85th percentile (not average) speeds. This guide provides 

references to the original studies. FHWA Office of Safety website. Available at: http://safety.fhwa.dot.gov/speedmgt/ref_mats/eng_count/ . An updated 

version is available at: http://safety.fhwa.dot.gov/speedmgt/ref_mats/eng_count/2014/reducing_speed.cfm .
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Potential Speed Reductions for Design and Traffic Calming Measures

Countermeasure Description Area Type Road Type Traffic Volume

85th Percentile 

Speed 

Reduction

(std. deviation)

Gateway Treatment Combined use of signs, monuments, 

landscaping, and potentially other 

traffic calming treatments at 

entrance to a neighborhood or 

community.

Urban Not specified Not specified 7%

(n/a)

Half Closure Physical blockage of one direction of 

traffic for a short distance on a twoway street

Urban Not specified

(typically 

local/residential)

Not specified 20%

(12%)

Lateral Shift Shifting of travel lanes from one side 

of road to other and back over 

distance

Urban Local Not specified 8%

(n/a)

Lateral Shift Shifting of travel lanes from one side 

of road to other and back, over a 

distance

Rural At city limits Not specified 25%

(9%)

Mini Traffic Circle 21 Circular, raised islands placed in 

middle of an intersection

Urban Not specified 240 - 10,910 11%

(9%)

Speed Humps 22 Rounded raised area across the road, 

typically 12 - 14’ long; 3 - 4” high

Urban Local 48 - 11,544 22%

(9%)

 

21 See BikeSafe case study on Seattle’s experience with implementing over 800 mini traffic circles. Available at: 

http://www.pedbikesafe.org/BIKESAFE/case_studies/casestudy.cfm?CS_NUM=503

22 Also see Table 3 in this document for CMF estimate for speed humps. 
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Potential Speed Reductions for Design and Traffic Calming Measures

Countermeasure Description Area Type Road Type Traffic Volume

85th Percentile 

Speed 

Reduction

(std. deviation)

Speed Humps 22 Rounded raised area across the road, 

typically 12 - 14’ long; 3 - 4” high

Not specified Local 400 - 4,362 20%

(6%)

Speed Humps 22 Rounded raised area across the road, 

typically 12 - 14’ long; 3 - 4” high

Urban Local 574 - 1,506 15%

(3%)

Speed Tables Long speed hump, typically 22’, flat in 

mid-portion with ramps on ends

Urban Not specified 198 - 14,500 16%

(9%)

Speed Tables Long speed hump, typically 22’, flat in 

mid-portion with ramps on ends

Rural

(Small town))

Not specified 1,480 14%

(3%)

Speed Tables Long speed hump, typically 22’, flat in 

mid-portion with ramps on ends

Not specified Residential 198 - 2,102 24%

(n/a)

Speed Cushion Speed hump typically 6 - 7’ wide that 

allows most emergency vehicles to 

straddle the hump

Urban Not specified 3,323 20%

(n/a) 

Speed Cushion Speed hump typically 6 - 7’ wide that

allows most emergency vehicles to 

straddle the hump

Urban Not specified 1,042 - 1,556 16 to 19% 

(n/a)

Table 5 shows potential crash effects for various pavement treatments, markings, and signs. 
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Table 5. Potential Crash Effects for Pavement Treatments, Markings and Signs.

CMFs for Pavement Treatments, Markings, and Signs

Countermeasure Description Area Type 

Road / 

Intersection 

Type

Traffic 

Volume Crash Types Crash Injury Severity 

CMF

(std. error)

CMF

Star

Rating

Enhanced Curve 

Delineation 23

Install new 

fluorescent curve 

signs or upgrade 

existing curve signs 

to fluorescent 

sheeting

Rural 2-lane, undiv. 260-

20,500

NonintersectionAll 0.82** 24

(0.077)

4

Enhanced Curve 

Delineation 23

Install new 

fluorescent curve 

signs or upgrade 

existing curve signs 

to fluorescent 

sheeting

Rural 2-lane, undiv. 900 -

20,500

NonintersectionFatal and Injury 0.75** 24

(0.127)

4

Enhanced Curve 

Delineation 23

Install chevron 

signs on horizontal 

curves

Rural 2-lane, undiv. 260 -

14,790

NonintersectionNighttime 0.75** 24

(0.095)

4

 

23 Source: Srinivasan, R., Baek, J., Carter, D., Persaud, B., Lyon, C., Eccles, K., Gross, F., Lefler, N. (2009). Safety Evaluation of Improved Curve Delineation.

(Report No. FHWA-HRT-09-045), Washington, DC: Federal Highway Administration.

24 The reductions were more prominent at locations with higher traffic volumes and sharper curves (curve radius less than 492 ft) and in locations with more 

hazardous roadsides (roadside hazard rating (RHR) of 5 or higher) compared to locations with less hazardous roadsides (RHR of 4 or lower). In addition, 

curves where more signs were either added or replaced (with a more retroreflective material) within the curve experienced larger reductions in crashes. An 

economic analysis revealed that improving curve delineation with signing improvements is a very cost-effective treatment with the benefit-cost ratio 

exceeding 8:1. More CMFs are available for other crash types.
Speed Management Toolkit

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CMFs for Pavement Treatments, Markings, and Signs

Countermeasure Description Area Type 

Road / 

Intersection 

Type

Traffic 

Volume Crash Types Crash Injury Severity 

CMF

(std. error)

CMF

Star

Rating

Enhance Curve 

Delineation 25

Install a 

combination of 

chevron signs, 

curve warning 

signs, and/or 

sequential flashing 

beacons

Not 

specified

Principal 

arterial, & 

other 

freeways and 

expressways

7,400 -

13,975

All All 0.606** 26

(0.07)

4

 

25 Source: Montella, A. (2009). Safety Evaluation of Curve Delineation Improvements. An Empirical Bayes Observational Before-After Study. Presented at the 

88th Annual Meeting of the Transportation Research Board, Compendium of Papers CD-ROM. Washington, DC.

26 CMFs also available for other crash types and conditions. The CMFs range from 0 .58 - 0 .59 for run-off road, and wet-road to .81 for all crash types - fatal 

and injury severities.
Speed Management Toolkit

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CMFs for Pavement Treatments, Markings, and Signs

Countermeasure Description Area Type 

Road / 

Intersection 

Type

Traffic 

Volume Crash Types Crash Injury Severity 

CMF

(std. error)

CMF

Star

Rating

Transverse (in 

lane) Rumble 

Strips for speed 

calming 

(intersection 

approaches) 27

Install transverse 

rumble strips (TRS) 

(also called in-lane 

rumble strips) on 

stop-controlled 

intersection 

approaches

Rural 3 & 4 leg 

minor road, 

stopcontrolled

Major 

road: 3265 

avg.;

Minor 

road: 801 

avg.

All Injury and Fatal 

(KA)

0.608**

(0.140)

4

Transverse (in 

lane) Rumble 

Strips for speed 

calming 

(intersection 

approaches) 27

Install transverse 

rumble strips (TRS) 

(also called in-lane 

rumble strips) on 

stop-controlled 

intersection 

approaches

Rural 3 & 4 leg 

minor road, 

stopcontrolled

Major 

road: 3265 

avg.;

Minor 

road: 801 

avg.

All Injury and Fatal 

(KAB)

0.785**

(0.107)

4

Transverse (in 

lane) Rumble 

Strips for speed 

calming 

(intersection 

approaches) 27

Install transverse 

rumble strips (TRS) 

(also called in-lane 

rumble strips) on 

stop-controlled 

intersection 

approaches

Rural 3 & 4 leg 

minor road, 

stopcontrolled

Major 

road: 3265 

avg.;

Minor 

road: 801 

avg.

All Injury and Fatal 

(KABC)

0.987

(0.109)

4

 

27 Source: Srinivasan, R., Baek, J., and Council, F. (2010). Safety Evaluation of Transverse Rumble Strips on Approaches to Stop-Controlled Intersections in Rural 

Areas, Journal of Transportation Safety and Security, Vol. 2(3), September 2010.
Speed Management Toolkit

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CMFs for Pavement Treatments, Markings, and Signs

Countermeasure Description Area Type 

Road / 

Intersection 

Type

Traffic 

Volume Crash Types Crash Injury Severity 

CMF

(std. error)

CMF

Star

Rating

Transverse (in 

lane) Rumble 

Strips for speed 

calming 

(intersection 

approaches)27

Install transverse 

rumble strips (TRS) 

(also called in-lane 

rumble strips) on 

stop-controlled 

intersection 

approaches

Rural 3 & 4 leg 

minor road, 

stopcontrolled

Major 

road: 3265 

avg.;

Minor 

road: 801 

avg.

All Property 

Damage Only 

(PDO)

1.191

(0.102)

4

Transverse (in 

lane) Rumble 

Strips for speed 

calming28

Install transverse 

rumble strips as 

traffic calming 

device

Suburban 

/ Urban

Local, 2-lane Not 

specified

All All 0.66**

(0.11)

4

Transverse (in 

lane) Rumble 

Strips for speed 

calming28

Install transverse 

rumble strips as 

traffic calming 

device

Suburban 

/ Urban

Local, 2-lane Not 

specified

All Serious, Minor 

Injury

0.64**

(0.12)

4

Transverse (in 

lane) Rumble 

Strips for speed 

calming28

Install transverse 

rumble strips as 

traffic calming 

device

Suburban 

/ Urban

Local, 2-lane Not 

specified

All Property 

Damage Only 

(PDO)

0.73 

(0.41)

2

 

28 Source: Elvik, R. and Vaa, T. (2004). Handbook of Road Safety Measures, Oxford, United Kingdom: Elsevier.
Speed Management Toolkit

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Table 6 provides estimates of speed reductions for a few other pavement treatments, markings and signs for which crash estimates 

may not be available. Note that some of the estimates are smaller than the measure of variability (standard deviation); percentage 

effects on speed may vary substantially by location or other factors, including prior speeds.

Table 6. Potential Speed Reductions for Pavement Treatments, Markings and Signs.29

Potential Speed Effects for Pavement Treatments, Markings, and Signs

Countermeasure Description Area Type Road Type Traffic Volume

85th Percentile 

Speed 

Reduction

(Std. deviation)

Converging Chevrons Type of transverse pavement 

markings forming chevron shape to 

create the illusion of traveling faster 

as well as the impression of narrower 

lanes

Rural Main Roads 2,300 7%

(6)

Converging Chevrons Type of transverse pavement 

markings forming chevron shape to 

create the illusion of traveling faster 

as well as the impression of narrower 

lanes

Rural Double-S curves Not specified 4

(n/a)

Converging Chevrons Type of transverse pavement 

markings forming chevron shape to 

create the illusion of traveling faster 

as well as the impression of narrower 

lanes

Urban Collectors Not specified 5%

(n/a)

 

29 Source for speed reduction estimates in this table: Engineering Countermeasures for Reducing Speeds (2009): A Desktop Reference of Potential 

Effectiveness was used as the primary source for the speed change estimates. This guide provides references to the original studies. FHWA Office of Safety 

website. Available at: http://safety.fhwa.dot.gov/speedmgt/ref_mats/eng_count/. 
Speed Management Toolkit

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Potential Speed Effects for Pavement Treatments, Markings, and Signs

Countermeasure Description Area Type Road Type Traffic Volume

85th Percentile 

Speed 

Reduction

(Std. deviation)

Converging Chevrons Type of transverse pavement 

markings forming chevron shape to 

create the illusion of traveling faster 

as well as the impression of narrower 

lanes

Urban Freeway 

Connectors

18,000 1%

(n/a)

Converging Chevrons Type of transverse pavement 

markings forming chevron shape to 

create the illusion of traveling faster 

as well as the impression of narrower 

lanes

Urban Exit Ramps Not specified 24%

(n/a)

Optical Speed Bars Series of white rectangular markings 

typically 1 foot wide placed just inside 

both edges of the lane and spaced 

progressively closer to create the 

illusion of traveling faster as well as 

the impression of narrower lane.

Rural Main Roads

(two studies)

Not specified, 

1000

2%

(n/a)

Optical Speed Bars Series of white rectangular markings 

typically 1 foot wide placed just inside 

both edges of the lane and spaced 

progressively closer to create the 

illusion of traveling faster as well as 

the impression of narrower lane.

Rural Curve Not specified 2%

(8%)

Optical Speed Bars Series of white rectangular markings 

typically 1 foot wide placed just inside 

both edges of the lane and spaced 

progressively closer to create the 

illusion of traveling faster as well as 

the impression of narrower lane.

Rural 2-lane; Tourist 

Area

Not specified 7%

(n/a)
Speed Management Toolkit

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Potential Speed Effects for Pavement Treatments, Markings, and Signs

Countermeasure Description Area Type Road Type Traffic Volume

85th Percentile 

Speed 

Reduction

(Std. deviation)

Optical Speed Bars Series of white rectangular markings 

typically 1 foot wide placed just inside 

both edges of the lane and spaced 

progressively closer to create the 

illusion of traveling faster as well as 

the impression of narrower lane.

Rural Freeway Curves 63,072 2%

(n/a)

Table 7 presents traffic management or operational measures with documented potential to reduce speeding-related crashes. 

Numerous other operations measures may also lower speeding-related and severe crashes, although they may not be intended 

primarily for those purposes, or there is less evidence of their effectiveness for speeding-related crash problems at this time. For 

example, other signal timing measures may help to separate conflicting traffic and person movements that could result in decreasing 

speeding-related crashes at signalized intersections, including crashes involving pedestrians, cyclists or transit users. The design of 

intersections also affects traffic speed and safety for all users, with wider intersections having potential to increase speeds and 

increase risk to pedestrians.30

 

30 Chandler, B.E., Myers, M.C., Atkinson, J.E., Bryer, T.E. et al. (2013). Signalized Intersections Informational Guide, Second Ed. Report No. FHWA-SA-13-027. 

Washington, DC: Federal Highway Administration. Available at: http://safety.fhwa.dot.gov/intersection/signalized/13027/fhwasa13027.pdf.
Speed Management Toolkit

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Another potential countermeasure is to use coordinated traffic signal progression along a corridor, a measure primarily intended to 

help manage the flow of traffic, but which may also help to manage the speed of traffic along certain corridors.

30, 31 Signal 

progression is estimated to reduce all collisions along a corridor from 10 to 20 percent.30

Table 7.Potential Crash Effects for Traffic Speed Management and Operations Measures.

CMFs for Traffic Speed Management and Traffic Operations Measures

Countermeasure Description Area 

Type Road Type Traffic Volume

Crash 

Types

Crash 

Injury 

Severity

CMF

(std. 

error)

CMF 

Star 

Rating

Variable Speed 

Limits32

Install Variable Speed 

Limit signs (from 40 to 

60 mph)

Urban Principal Arterial 

Interstate

(1 study site)

Not 

specified

All All 0.92

(n/a)

4

Decrease Speed 

Limit on 

Expressway33

Lower posted speed 

limit on expressway 

from 100 to 80 km/hr

(Korea)

Not 

specified

Principal Arterial Other 

Freeways and 

Expressways (divided by 

median)

3,100 to 

50,300 

All All 0.855* 

(0.079)

4

Decrease Speed 

Limit on 

Expressway33

Lower posted speed 

limit on expressway 

from 100 to 80 km/hr

(Korea)

Not 

specified

Principal Arterial Other 

Freeways and 

Expressways (divided by 

median)

3,100 to 

50,300 

SpeedrelatedAll 0.912

(0.161) 

4

 

31 Koonce, P., Rodegerdts, L., Lee, K., Quayle, S., Beaird, S., Braud, C., Bonneson, J., Tarnoff, P., and Urbanik, T. (2008). Traffic Signal Timing Manual. (Report No. 

FHWA-HOP-08-024), Washington, DC: Federal Highway Administration. Available at: 

http://ops.fhwa.dot.gov/publications/fhwahop08024/fhwa_hop_08_024.pdf.

32 Source: Bham, G. H., Long, S., Baik, H., Ryan, T., Gentry, L., Lall, K., Arezoumandi, M., Liu, D., Li, T., and Schaeffer, B. (2010). Evaluation of Variable Speed 

Limits on I-270/I-255 in St. Louis. (Report No. RI08-025), Rolla, MO: Missouri University of Science and Technology.

33 Source: Park, E.S., Park, J., Lomax, T.J. (2010). A fully Bayesian multivariate approach to before–after safety evaluation. Accident Analysis & Prevention 42, 

1118-1127. 
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CMFs for Traffic Speed Management and Traffic Operations Measures

Countermeasure Description Area 

Type Road Type Traffic Volume

Crash 

Types

Crash 

Injury 

Severity

CMF

(std. 

error)

CMF 

Star 

Rating

Decrease Speed 

Limit on 

Expressway33

Lower posted speed 

limit on expressway 

from 100 to 80 km/hr

(Korea)

Not 

specified

Principal Arterial Other 

Freeways and 

Expressways (divided by 

median)

3,100 to 

50,300 

All Fatal, 

serious 

injury

1.036

(0.172)

4

Decrease Speed 

Limit on 

Expressway33

Lower posted speed 

limit on expressway 

from 100 to 80 km/hr

(Korea)

Not 

specified

Principal Arterial Other 

Freeways and 

Expressways (divided by 

median)

3,100 to 

50,300 

All Minor 

injury

0.792**

(0.086)

4

Change Signal 

Phasing 34

Change from 

permissive to 

protected signal 

phasing

Not 

stated

Signalized, 3-, 4-, > 4-legs Not 

specified

All All 0.94

(n/a)

HSM

Change Signal 

Phasing 35

Convert from 

permitted-protected 

to protected on major 

approach 

Urban Signalized, high speed Not 

specified

Angle All 0.01**

(0.02)

5

Change Signal 

Phasing 35

Convert from 

permitted-protected 

to protected on major 

approach

Urban Signalized, high speed Not 

specified

All All 0.58*

(0.19) 

3

 

34 AASHTO (2010). Highway Safety Manual, 1st ed. 

35 Source: Davis, G.A. and Aul, N. (2007). Safety Effects of Left-Turn Phasing Schemes at High-Speed Intersections, (Report No. MN/RC-2007-03), Minnesota 

Department of Transportation. [CMFs also available for left turn and total intersection crashes from NCHRP Report 705: Evaluation of Safety Strategies and 

Signalized Intersections.
Speed Management Toolkit

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CMFs for Traffic Speed Management and Traffic Operations Measures

Countermeasure Description Area 

Type Road Type Traffic Volume

Crash 

Types

Crash 

Injury 

Severity

CMF

(std. 

error)

CMF 

Star 

Rating

Change Signal 

Phasing 35

Convert from 

permitted-protected 

to protected on minor 

approach

Urban Signalized, high speed Not 

specified

Angle All 0.01**

(0.02)

5

Change Signal 

Phasing 35

Convert from 

permitted-protected 

to protected on minor 

approach

Urban Signalized, high speed Not 

specified

All All 0.99

(0.34)

1

Change Signal 

Phasing 35

Convert from 

permitted to protected 

on minor approach

Urban Signalized, high speed Not 

specified

Angle All 0.01**

(0.01)

5

Change Signal 

Phasing 35

Convert from 

permitted to protected 

on minor approach

Urban Signalized, high speed Not 

specified

All All 0.83

(0.44)

1

Table 8 show enforcement and publicity measures that have crash modification factor estimates. While many other types of speed 

enforcement are thought to reduce speeding and related crashes, recent high quality evidence of the extent of effects is lacking. 
Speed Management Toolkit

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Table 8. Potential Crash Effects for Enforcement and Publicity Countermeasures. 

CMFs for Enforcement and Publicity Countermeasures

Countermeasure Description Area 

Type

Road / 

Intersection 

Type

Traffic 

Volume

Crash 

Type

Crash Injury 

Severity 

CMF 

(std. error)

CMF 

Star

Rating 

Automated Speed 

enforcement36

Implement 

automated speed 

enforcement 

cameras 

All All Not 

specified

All Fatal, 

Serious, 

Minor Injury

0.83**

(.01)

5

Enforcement with 

Mobile Speed 

Cameras37

Implement mobile 

automated camera 

enforcement 

following publicity 

phase 

Urban Not specified Not 

specified

All All 0.84** 

(0.07)

4

Enforcement with 

Mobile Speed 

Cameras37

Implement mobile 

automated camera 

enforcement 

following publicity 

phase

Urban Not specified Not 

specified

All Fatal, 

Serious, 

Minor injury

0.85

(0.11)

3

Enforcement with 

Mobile Speed 

Cameras37

Implement mobile 

automated camera 

enforcement 

following publicity 

phase

Urban Not stated Not 

specified

All Property 

damage only 

(PDO)

0.82

(0.11)

3

 

36 Source: AASHTO (2010). Highway Safety Manual, 1st Ed. Washington, D.C.: American Association of State Highway and Transportation Officials. [From various 

studies.]

37 Source: Moon, J.P. and J. E. Hummer. (2010). Estimating the Longer-Term Safety Effects of Speed Enforcement Cameras in Charlotte, NC. TRB 89th Annual 

Meeting Compendium of Papers CD-ROM. 
Speed Management Toolkit

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CMFs for Enforcement and Publicity Countermeasures

Countermeasure Description Area 

Type

Road / 

Intersection 

Type

Traffic 

Volume

Crash 

Type

Crash Injury 

Severity 

CMF 

(std. error)

CMF 

Star

Rating 

Enforcement with 

Fixed Speed 

Cameras38, 39

Implementation of 

fixed speed camera 

enforcement

Urban Principal 

Arterial 

(Beltway)

Not 

specified

All 

(nonpeak 

hours) 

All 0.46**

(0.07)

4

Enforcement with 

Fixed Speed 

Cameras38,39

Implementation of 

fixed speed camera 

enforcement

Urban Principal 

Arterial 

(Beltway)

Not 

specified

Single 

vehicle

(nonpeak 

hours)

All 0.37**

(0.09)

4

Enforcement with 

Fixed Speed 

Cameras38,39

Implementation of 

fixed speed camera 

enforcement

Urban Principal 

Arterial 

(Beltway)

Not 

specified

All 

(nonpeak 

hours)

Serious, 

Minor injury

0.52**

(0.14)

3

 

38 Source: Shin, K., Washington, S., van Schalkwyk, I., (2009). Evaluation of the Scottsdale Loop 101 automated speed enforcement demonstration program. 

Accident Analysis & Prevention 41, 393-403. 

A number of other disaggregate CMF estimates are also available from this study.

39 Target crashes were defined as those occurring during non-peak hours (6 to 9 am and 4 to 7 pm weekdays), as little exceeding limits was measured during 

peak hours. 
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CMFs for Enforcement and Publicity Countermeasures

Countermeasure Description Area 

Type

Road / 

Intersection 

Type

Traffic 

Volume

Crash 

Type

Crash Injury 

Severity 

CMF 

(std. error)

CMF 

Star

Rating 

Automated Section 

Speed 

Enforcement40

Implement 

automated section 

speed enforcement 

system (enforces 

average speed over 

a distance)

Not 

specified

Principal 

Arterial, 

Other 

Freeways and 

Expressways 

(median 

divided; 

speed limit 

130 km/h (81 

mph)

23,000 -

42,000 ADT

All All 0.69**41

(0.04)

4

Automated Section 

Speed 

Enforcement40

Implement 

automated section 

speed enforcement 

system (enforces 

average speed over 

a distance)

Not 

specified

Principal 

Arterial, 

Other 

Freeways and 

Expressways 

(median 

divided; 

speed limit 

130 km/h (81 

mph)

23,000 -

42,000 ADT

All Fatal, Serious 

Injury

0.44**

(0.07)

4

 

40 Source: Montella, A., Persuad, B., D’Apuzzo, M., Imbriani, L. (2012). Safety Evaluation of an Automated Section Speed Enforcement System. Presented at the 

91st Annual Meeting of the Transportation Research Board, Paper No. 12-0226, Washington, DC.

Other CMFs also available. Study from Italy.

41 CMFs at 12 months (0.66, 0.07 s.e.); at 18 months (0.68, 0.07 s.e.); and at 24 months (0.69, 0.07). 
Speed Management Toolkit

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CMFs for Enforcement and Publicity Countermeasures

Countermeasure Description Area 

Type

Road / 

Intersection 

Type

Traffic 

Volume

Crash 

Type

Crash Injury 

Severity 

CMF 

(std. error)

CMF 

Star

Rating 

Automated Section 

Speed 

Enforcement40

Implement 

automated section 

speed enforcement 

system (enforces 

average speed over 

a distance)

Not 

stated

Principal 

Arterial, 

Other 

Freeways and 

Expressways 

(median 

divided; 

speed limit 

130 km/h (81 

mph)

23,000 -

42,000 ADT

Curves All 0.57**

(0.08)

4

Earned Publicity 

Associated with 

Mobile Camera 

Enforcement37

Publicity Associated 

with Mobile 

Camera 

Enforcement

Urban Not specified Not 

specified

All All 0.92

(0.06)

3

Earned Publicity 

Associated with 

Mobile Camera 

Enforcement37

Publicity Associated 

with Mobile 

Camera 

Enforcement

Urban Not specified Not 

specified

All Fatal, 

Serious, 

Minor injury

0.9

(0.12)

3

Speed 

Display/Feedback 

Device42

Individual driver 

speed 

display/feedback 

Not 

specified

Not specified Not 

specified

All All 0.54** 

(0.17 )

 

42 Source: Elvik, R. and Vaa, T., Handbook of Road Safety Measures. (2004). Oxford, United Kingdom: Elsevier. (Multiple original studies.) 
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As mentioned earlier, CMFs from Table 9 and Table 10 may be used to estimate crash effects for countermeasures that reduce 

average travel speed, but for which estimates of crash effects are unavailable.

Table 9. Potential Injury Crash Effects (CMFs) of Changes in Average 

Operating Speed for a Road Section. [Based on Table 3E-2. Crash 

Modification Factors for Changes in Average Operating Speed, Highway 

Safety Manual, AASHTO, 2010, p. 3-57. Used by Permission.]

43

CMFs - Injury Crashes

Change 

in avg. 

speed 

(mph)

Baseline 

Average 

Speed

Baseline 

Average 

Speed

Baseline 

Average 

Speed

Baseline 

Average 

Speed

Baseline 

Average 

Speed

Baseline 

Average 

Speed

30

mph

40

mph

50

mph

60

mph

70

mph

80

mph

-5 0.57 0.66 0.71 0.75 0.78 0.81

-4 0.64 0.72 0.77 0.8 0.83 0.85

-3 0.73 0.79 0.83 0.85 0.87 0.88

-2 0.81 0.86 0.88 0.9 0.91 0.92

-1 0.9 0.93 0.94 0.95 0.96 0.96

0 1 1 1 1 1 1

1 1.1 1.07 1.06 1.05 1.04 1.04

2 1.2 1.15 1.12 1.1 1.09 1.08

3 1.31 1.22 1.18 1.15 1.13 1.12

4 1.43 1.3 1.24 1.2 1.18 1.16

5 1.54 1.38 1.3 1.26 1.22 1.2

 

43 “NOTE: Although data used to develop these CMFs are international, the 

results apply to North American conditions.” (AASHTO, 2010. Highway 

Safety Manual, 1st ed. Washington, DC: American Association of Highway 

and Transportation Officials.)

Table 10. Potential Fatal Crash Effects (CMFs) of Changes in Average 

Operating Speed for a Road Section. [Based on Table 3E-2. Crash 

Modification Factors for Changes in Average Operating Speed, Highway 

Safety Manual, AASHTO, 2010, p. 3-57. Used by Permission.]

43

CMFs - Fatal Crashes

Change 

in avg. 

speed 

(mph)

Baseline 

Average 

Speed

Baseline 

Average 

Speed

Baseline 

Average 

Speed

Baseline 

Average 

Speed

Baseline 

Average 

Speed

Baseline 

Average 

Speed

30

mph

40

mph

50

mph

60

mph

70

mph

80

mph

-5 0.22 0.36 0.48 0.58 0.67 0.75

-4 0.36 0.48 0.58 0.66 0.73 0.8

-3 0.51 0.61 0.68 0.74 0.8 0.85

-2 0.66 0.73 0.79 0.83 0.86 0.9

-1 0.83 0.86 0.89 0.91 0.93 0.95

0 1 1 1 1 1 1

1 1.18 1.14 1.11 1.09 1.07 1.05

2 1.38 1.28 1.22 1.18 1.14 1.1

3 1.59 1.43 1.34 1.27 1.21 1.16

4 1.81 1.59 1.46 1.36 1.28 1.21

5 2.04 1.75 1.58 1.46 1.36 1.27
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Keys to Successful Speed Management Programs Tip Sheets

Two resources were developed to help local agencies, in particular, build an effective communications program and leverage 

resources to increase support of and effectiveness of the speed management program. Many of the ideas in the tip sheets may also 

be useful for regional or statewide speed management communications programs or partnership-building.

The two tip sheets, on the following pages, are as follows:

 Build a Coalition of Supporters and Partners.

 Keys to Communication Success.
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Build a Coalition 

of Supporters and Partners

Tip Sheet

GETTING BUY IN

Create early buy-in from the community:

Reach out to leading individuals (see potential partner list below) to ask for their perspective and campaign support (and 

track your contact with and input from each on a spreadsheet for easy reference).

“Frame the problem” to address their specific concerns (teen accidents, high-speeding areas, child or school areas safety, 

pedestrian and bicycle safety, the social, monetary, environmental impact, or public health threat of speed-related accidents 

and fatalities, for instance).

Customize campaign messages with their input, which also helps create buy-in. 

MAKING CONTACT

Prepare for your contact with key people:

Do your homework. (Who are the largest employers? What community or neighborhood organizations are concerned about 

traffic safety and injury? Who will be most receptive to your message? What sort of messages do they send with their ads or 

community outreach?)
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Create a “call script” to tighten your approach and be sure you have covered important selling points.

Start with the people most likely to be receptive (hospital staff members already understand and value safety so they are 

likely partners, for instance). 

Increase your contact success:

Ask to speak with a specific person in a potential partner’s organization – perhaps the “safety or security director” 

(manufacturing plants, large companies), “community programs or outreach director” (community organizations), 

“communications or public relations director” (corporations), or “advertising or community relations director” (newspapers 

or TV). Search online for staff directories to see if you can ask for that person by name.

Mention other partners to new contacts to increase your credibility.

Contact key people at organizations that have a direct vested interest in the outcome (a hospital), tremendous grassroots 

outreach (a utility company), or a large audience (major retailers/employers), particularly if their target demographic 

matches yours. To start, identify local:

Hospitals

Businesses, including major employers and retailers

Churches

Utility companies

Community organizations 

Colleges, universities, private schools

Safety organizations

Automobile and health insurers

Health care providers

Chambers of commerce

Military bases

Newspapers and television stations 
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GAINING SUPPORT

Suggest ways partners can participate such as:

Buying advertising on radio, television, billboards, or in print (a business can sponsor morning traffic reports on behalf of the 

campaign, for instance).

Flagging existing or planned advertising with campaign messages or reminders.

Sponsoring promotional materials (co-brand campaign and your partner’s name/logo on appropriate items such as coffee 

wrappers and car decals).

Hosting campaign speakers (at little or no cost to the sponsor) or events.

Distributing campaign materials to employees or members (at little or no cost).

Posting information and a link to the campaign website on the partner Intranet or website (at little or no cost).

SUSTAINING SUPPORT

Reciprocate partner support:

Post partner efforts/contributions on the campaign website and social media.

Send press releases to praise partner efforts/contributions.

Share media opportunities/spotlight with partners at every opportunity.

Refresh the partner network:

Ask partners who else they would like to see in the network.

Continually seek new partners to ensure a steady level of outreach over a longer period of time and gain creative input from 

fresh perspectives.
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Keys to Communication Success

Tip Sheet

FUNDAMENTALS

Be clear about what you are trying to accomplish.

Describe specific, desired outcomes. Quantify what will be viewed as “success.”

Figure out whom you need to reach to achieve the outcomes.

Consider how you will best influence their action toward the outcome you desire.

Track and measure your results.

Build a coalition of supporters and partners.

(See “Build a Coalition” Tip Sheet)
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Localize campaign as much as possible.

The most effective campaigns support enforcement (or engineering) activities. (e.g. “This is why we are ... enforcing close to 

the limit, in Town, on rural roads, etc.)

Appropriate “look” (local geography/climate/ feel) is important to gaining acceptance for messages. Penetrating resistance 

to information overload begins with messages that feel relevant, personal, and local.

Appropriate “voice” is important to gaining acceptance, particularly with young audiences, Leverage peer-to-peer 

communication with young audiences by holding a poster, social media, or video contest with local media arts students or 

other stakeholders (e.g., environmental science programs, medical students, etc.), judged by local industry leaders with 

technical assistance from appropriate professionals. Use winning materials to promote the campaign.

Customize messages with input from community members (see “Building Support Tip Sheet”). 

Use Several Types of Media.

Offer a unified message across a mixture of media to reach the target audience from several directions. The words may 

change but a simple, consistent message should underlie each communication. 

Reach teens and young adults through their use of technology and try to leverage respected peers or other figures to 

“deliver” the message.

Reach adults through radio ads or Public Service Announcements (PSAs) during drive time (rush hours).

Reach audiences through face-to-face communication as well as media. Even social media is based on the fact that human 

beings are hard-wired for personal connection.

Consider bilingual messaging where appropriate.

Create a simple campaign website and/or social media site to allow audience members who align with you to share

information through their networks. Several options exist for free websites that can be created in one to two hours by a 

person with no technical experience.

Develop an interactive component to your campaign, possibly through your website. Consider a simple incentive for 

interaction like an online “Safe Driver Pledge” that serves as an entry form to a weekly/monthly drawing for cash/prizes. The

site can suggest “Tweeting” or recommending the site to friends so they can take the pledge and enter to win. Prizes can be 

provided by local sponsors or partners, boosting their visibility in the campaign. 

Create an interactive display at a health fair, street fair, farmer’s market, community, or company event. Simple games that 

engage families may help children influence parents to pay attention to driving speed.
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Build a platform.

Commit to a plan with roles, responsibilities, a timeline, and a calendar of activities, creating an infrastructure for 

coordination and growth of the effort.

Inform (and annually update) local leaders, including lawmakers, officials, policy chiefs, school board officers, 

college/university administrations, military base communicators, civic leaders, and peer groups who have a stake in the 

outcome. Enlist their involvement, in accordance with your plan.

TACTICS

Repeat the message.

Deliver the same message to your target audience several times. Studies show that slight variation in message (who says it, 

the exact words) may help repeated messages penetrate more effectively. Despite debate, there does not appear to be a 

magic number for the frequency of repetition, but many sources cite three to seven repetitions as the number of times a 

person must hear a message to begin to feel likely to act on it. 

Search for credible sources who are writing or talking about speed and safety issues within your community. They may be 

willing to carry your message through a new communication or a follow-up to a previous one. 

Provide message delivery devices to partners and local officials or other stakeholders (monthly messages to include with 

bills, paychecks, or advertisements; a paragraph or two for a local leader to insert into a speech; a sample pledge and usage

guidelines; compelling and consistent print and web-ready content). Consider developing a sample agreement for a 

spokesperson to make it easy to enlist such help.
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Leverage local human resources.

Hire campaign interns from local colleges in subject areas related to your effort (and pay them with small scholarships or 

inexpensive, but desirable, items such as gift cards, phones or cameras).

Recruit high school student volunteers who want to earn community service hours by helping you.

Appoint campaign liaisons within the business community – and ask them to enlist members of their networks.

Leverage pre-existing events by sending a campaign representative to:

Partner sites, perhaps to speak at a regularly scheduled luncheon. 

Career days at high schools to talk about employment-related driving and hand out informative pamphlets. 

University classes to give students a background briefing on the campaign and hand out information or show a DVD with 

information they will find useful.

Neighborhoods, via health, safety, craft, art, holiday or other gatherings, and create relevant “hooks” to your campaign (i.e., 

coloring books or “paint your family car” stations for kids at a craft fair). Provide informative campaign materials.

Sporting events – or engage the cooperation of a local sports figure to help deliver your message at a focal point in the 

event.

Think creatively about budget.

Leverage local partners to help carry your message to their networks. Their credibility with their own audience may exceed 

yours.

Evaluate media realities (budget and effectiveness of paid vs. earned media, for instance). 

Recognize that “earning” media today does not always mean editorials and traditional "news" pieces. It could involve social 

media, emails, promotional items, or contests that may or may not be covered by news media but will help deliver your 

message through a credible third party.

Remember that earned media also includes delivering messages through partner publications or any vehicle partners use to 

communicate effectively with their own audiences.
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Be creative in planning press-worthy events.

Make events camera-friendly (action-oriented and demonstrating points rather than describing them). 

Provide professional quality video footage (known as “b roll”) that reporters can use to illustrate your subject matter as they 

speak about your campaign.

Be sure to deliver new information. After all, this is the “news” media.

Enlist local individuals to tell the story through their own relevant experiences. There is a reason reporters call their pieces 

“stories.”

SUSTAINABILITY

Update your initial plan annually, for the duration of the campaign, including lessons learned. 

Embed ownership among stakeholders for a specific period of time (i.e., ask for a commitment to the issue beyond the 

campaign).

Continue to seek new partners who may have new ideas and can replace those whose involvement is waning.

Be generous with praise for your partners.
For More Information:

Visit http://safety.fhwa.dot.gov/

FHWA, Office of Safety

Guan Xu

gxu@dot.gov

FHWA-SA-15-017