Safe System Approach for 

Speed Management
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Cover Image credit. Luana Broshears.
Technical Report Documentation Page

1. Report No. 

FHWA-SA-23-002

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

4. Title and Subtitle 

Safe System Approach for Speed Management

5. Report Date

May 2023

6. Performing Organization Code

7. Authors

 Wes Kumfer, Lewis Martin, Shane Turner, Luana Broshears

8. Performing Organization 

Report No.

9. Performing Organization Name and Address

Institute of Transportation Engineers 

1617 Eye Street NW, Suite 550

Washington, DC 20006

10. Work Unit No. (TRAIS)

11. Contract or Grant No.

DTFH6116D00055

12. Sponsoring Agency Name and Address

U.S. Department of Transportation 

Federal Highway Administration

1200 New Jersey Ave., SE 

Washington, DC 20590

13. Type of Report and 

Period Covered

 

14. Sponsoring Agency Code

HSA

15. Supplementary Notes

This report was produced under the direction of Anyesha Mookherjee, FHWA Office of Safety. The ITE Project Manager was 

Lisa Fontana Tierney.

16. Abstract

This report will help practitioners understand the impacts of speed on traffic safety and explore the link between speed 

management and the Safe System Approach by introducing a five-stage Safe System Approach for Speed Management 

framework. The five stages are establishing a vision and building consensus for speed management; collecting and 

analyzing speed and safety data; prioritizing locations for speed management proactively; selecting speed management 

countermeasures; and conducting ongoing monitoring, evaluation, and adjustment

Case studies and examples are interspersed throughout the report and in the appendix, demonstrating how agencies have 

been able to overcome institutional barriers and rally behind Safe System Approach principles to enact speed management 

programs with proven, measurable reductions in operating speeds and crashes.

17. Key Words

Safe System Approach, speed management, target speed, speed limits

18. Distribution Statement 

No restrictions. 

19. Security Classif. (of this 

report) 

Unclassified

20. Security Classif. (of this 

page) Unclassified

21. No of Pages

 116

22. Price 

 N/A

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

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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

TABLE OF CONTENTS

EXECUTIVE SUMMARY ........................................................................................................................1

1. INTRODUCTION................................................................................................................................3

1.1. THE NATIONAL ROADWAY SAFETY STRATEGY’S VISION FOR SPEED MANAGEMENT........... 5

2. THE RATIONALE FOR A SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT .......................7

2.1. SPEED AND CRASHES ........................................................................................................................... 8

2.1.1. HUMAN TOLERANCE TO SPEED....................................................................................................... 9

2.2. SPEED LIMITS AND SAFETY OUTCOMES ........................................................................................11

2.2.1. SETTING SAFER SPEED LIMITS ..............................................................................................11

2.2.2. THE IMPORTANCE OF REVIEWING SPEED LIMITS ........................................................... 14

2.2.3. INTERNATIONAL SPEED LIMIT PRACTICES ....................................................................... 14

2.3. SPEED AND ROADWAY DESIGN....................................................................................................... 15

2.4. SPEED AND VEHICLE DESIGN ........................................................................................................... 16

2.5. SPEED AND THE SAFE SYSTEM APPROACH................................................................................... 16

2.6. INTEGRATING SPEED MANAGEMENT AND SYSTEMIC SAFETY IN THE SAFE SYSTEM 

APPROACH ................................................................................................................................................... 17

2.6.1. OVERVIEW OF SPEED MANAGEMENT PRACTICES........................................................... 17

2.6.2. TRAFFIC SAFETY MANAGEMENT AND ANALYTICAL FRAMEWORKS........................... 18

3. THE SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT......................................................21

3.1. ESTABLISHING A VISION AND BUILDING CONSENSUS FOR SPEED MANAGEMENT............ 23

3.1.1. EXAMINE THE EXISTING LEGAL CONSTRAINTS AND SOCIOPOLITICAL FACTORS IN 

YOUR JURISDICTION.......................................................................................................................... 24

3.1.2. DETERMINING THE PRACTICAL SCOPE OF SPEED MANAGEMENT ACTIVITIES......... 24

3.1.3. ESTABLISHING A VISION FOR SPEED MANAGEMENT: MECHANISMS FOR STATE 

AGENCIES............................................................................................................................................. 28

3.1.4. ESTABLISHING A VISION FOR SPEED MANAGEMENT: MECHANISMS FOR LOCAL 

AGENCIES............................................................................................................................................. 31

3.1.5. EXAMPLES OF ESTABLISHING A VISION AND BUILDING CONSENSUS FOR SPEED 

MANAGEMENT ................................................................................................................................... 33

3.2. COLLECTING AND ANALYZING SPEED AND SAFETY DATA ....................................................... 35

3.2.1. USING A DATA-INFORMED APPROACH............................................................................... 35

3.2.2. RELEVANT DATA FOR A SPEED MANAGEMENT PROGRAM........................................... 35

3.2.3.QUALITY DATA ARE KEY......................................................................................................... 37

3.2.4. EXAMPLES OF COLLECTING AND ANALYZING SPEED AND SAFETY DATA................ 38

3.3. PRIORITIZING LOCATIONS FOR SPEED MANAGEMENT PROACTIVELY .................................. 39

3.3.1. PRIORITIZING LOCATIONS FOR SYSTEMIC COUNTERMEASURE IMPLEMENTATION.......39

3.3.2. SCHEMES FOR PRIORITIZATION.......................................................................................... 41

3.3.3. EXAMPLES OF PROACTIVELY PRIORITIZING LOCATIONS FOR SPEED MANAGEMENT ...43
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

3.4. SELECTING SPEED MANAGEMENT STRATEGIES ..........................................................................44

3.4.1. DETERMINE APPROPRIATE SPEED LIMITS TO MATCH TARGET SPEEDS ......................44

3.4.2. INFORM THE PUBLIC ABOUT SPEED MANAGEMENT BENEFITS TO BUILD SUPPORT ......44

3.4.3. IDENTIFY AND IMPLEMENT ROADWAY REDESIGN OR BEHAVIORAL TREATMENTS 

TO SUPPORT SPEED LIMIT CHANGES ............................................................................................ 45

3.4.4. COUNTERMEASURES FOR IMPROVING SPEED LIMIT COMPLIANCE ........................... 47

3.4.5. SPEED MANAGEMENT RESOURCES ....................................................................................48

3.4.6. EXAMPLES OF SELECTING SPEED MANAGEMENT COUNTERMEASURES .................. 50

3.5. ONGOING MONITORING, EVALUATION, AND ADJUSTMENT ................................................... 51

3.5.1. MONITORING AND DATA COLLECTION .............................................................................. 52

3.5.2. EVALUATE CURRENT SPEED MANAGEMENT EFFORTS ................................................... 52

3.5.3. SPEED ENFORCEMENT ........................................................................................................... 53

3.5.4. EDUCATION OF ROAD USERS ............................................................................................... 54

3.5.5. USEFUL TECHNOLOGIES ....................................................................................................... 55

3.5.6. EXAMPLES OF MONITORING, EVALUATION, AND ADJUSTMENT ................................ 55

4. CONCLUSION ..................................................................................................................................57

APPENDIX – CASE STUDIES ..............................................................................................................59

CASE STUDY A.1. WASHINGTON STATE INJURY MINIMIZATION AND SPEED MANAGEMENT 

—STATE OF WASHINGTON, USA ............................................................................................................. 59

CASE STUDY A.2. VIDEO-BASED NETWORK-WIDE SPEED AND SPEEDING ANALYSIS—

BELLEVUE, WASHINGTON, USA .............................................................................................................. 62

CASE STUDY A.3. 2020 VISION ZERO: SPEED MANAGEMENT—FREMONT, CALIFORNIA, USA 67

CASE STUDY A.4. AUTOMATED SPEED ENFORCEMENT—MONTGOMERY COUNTY, 

MARYLAND, USA......................................................................................................................................... 70

CASE STUDY A.5. NEW YORK CITY’S SPEEDING SOLUTIONS TOOLKIT—NEW YORK CITY, 

NEW YORK, USA .......................................................................................................................................... 73

CASE STUDY A.6. MULTI-DISCIPLINARY APPROACH FOR SPEED REDUCTION CITYWIDE—

PORTLAND, OREGON, USA ....................................................................................................................... 77

CASE STUDY A.7. SEATTLE SYSTEMIC SPEED LIMIT REDUCTION—SEATTLE, WASHINGTON, 

USA ................................................................................................................................................................ 81

CASE STUDY A.8. AUCKLAND TRANSPORT SAFE SPEEDS—AUCKLAND, NEW ZEALAND ........ 86

CASE STUDY A.9. NETWORK-WIDE SPEED LIMIT REDUCTION—MORNINGTON PENINSULA, 

AUSTRALIA ................................................................................................................................................... 89

CASE STUDY A.10. SPEED LIMIT REDUCTION ON URBAN ROADS—REPUBLIC OF KOREA ........ 92

REFERENCES .......................................................................................................................................95

TABLE OF CONTENTS (continued)
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

LIST OF FIGURES

Figure 1. The Safe System Approach. ............................................................................................................................... 4

Figure 2. Comparison of pedestrian risk curves.......................................................................................................... 10

Figure 3. The Safe System Approach for Speed Management Framework. ..................................................... 21

Figure 4. Percentage of motorists speeding. ...............................................................................................................64

Figure 5. Bel-Red Road and NE 30th Street in Bellevue. ..........................................................................................65

Figure 6. Speed heatmap at the Bel-Red Road and NE 30th Street intersection............................................65

Figure 7. Through driver speeding to cross red light................................................................................................65

Figure 8. Striped median to reduce lane widths in Fremont..................................................................................68

Figure 9. Montgomery County safe-speed camera locations (outside of Speed Camera Corridors). .....71

Figure 10. Speed limit sign used in combination with automated enforcement. .......................................... 74

Figure 11. Lincoln Center Bowtie Street improvements included reduced lane width and turn calming.....75

Figure 12. Example of road configuration in Portland after street redesign from five lanes to three lanes. 77

Figure 13. Simplified speed limit matrix for fatal crash reduction by mode.....................................................79

Figure 14. New speed limit sign on Greenwood/Phinney Avenue North..........................................................81

Figure 15. Mornington Peninsula Safer Speeds Trial. ................................................................................................90
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

LIST OF TABLES

Table 1. Safe System elements and how they relate to safe speeds...................................................................... 7

Table 2. Speeding-related fatalities and injuries in the United States, from 2010 to 2021............................. 9

Table 3. Example of a proposed safer speed limits model in the Netherlands, alongside the existing 

general speed limits. ............................................................................................................................................................ 12

Table 4. Summary of speed and crash study results. ................................................................................................ 13

Table 5. Probability of fatality or serious injury corresponding for different crash types............................26

Table 6. FDOT Design Manual target speeds and speed management techniques......................................27

Table 7. Components of a Vision Zero plan that addresses speed.......................................................................33

Table 8. Complementary speed management infrastructure treatments: speed and crash reductions....46

Table 9. Speed limit evaluation data collection in Seattle.......................................................................................84

Table 10. Outcomes of speed limit reductions in Seattle. .......................................................................................85

Table 11. Option 3 estimated costs and benefit table...............................................................................................88

Table 12. Korea case study – current status of lowering speeds across Korea.................................................93

Table 13. Korea case study – results of speed limit changes. .................................................................................94
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

GLOSSARY OF TERMS

The following section defines several of the key speed-related terms relevant to the Safe System 

Approach for Speed Management framework. The definitions provided here are intended to provide 

clear and consistent use of these terms throughout this report.

Design Speed – Geometric roadway design practices in the United States use design controls and 

criteria such as those from the American Association of State Highway and Transportation Officials 

(AASHTO) A Policy on Geometric Design of Highways and Streets, also known as the Green Book. 

AASHTO defines design speed as “a selected speed used to determine the various geometric design 

features of the roadway such as horizontal alignment, vertical alignment, and cross-section design 

elements” (AASHTO 2018).

Kinetic Energy – The energy of a moving object is defined as kinetic energy, and kinetic energy 

is directly proportional to the object’s mass and velocity. The human body has limits for tolerating 

crash forces; when kinetic energy exceeds a certain threshold, a fatal or serious injury occurs. The 

Safe System Approach framework prioritizes accommodating human injury tolerances by designing 

and operating transportation systems to reduce kinetic energy transfer in the event of a crash 

(FHWA 2020a). The reduction in kinetic energy transfer can be achieved primarily through speed 

management (Kumfer, LaJeunesse, Sandt, and Thomas 2019).

Operating Speed – Operating speed is defined as a speed at which a driver operates a typical 

vehicle, or a speed at which the overall traffic operates during free flow conditions. Under free flow 

conditions, motorist speed is not affected by an upstream or downstream traffic control device 

(e.g., traffic signal) or by the presence of other vehicles in the same, opposing, or crossing traffic 

stream. Operating speed is a general term that can refer to speed values such as the average, pace, 

or 85th percentile speeds (ITE 2016).

Pace – Pace is defined as the 10 mph speed range representing the speeds of the largest percentage 

of vehicles in the traffic stream.

Self-Enforcing Roadways – A self-enforcing or self-explaining roadway is a roadway that is 

planned and designed to encourage drivers to select operating speeds consistent with the posted 

speed limit.

Speed Distribution/85th Percentile Speed – Speed distribution is the arrangement of speed values 

showing their observed frequency of occurrence. The 85th percentile speed is defined as the speed 

at or below which 85 percent of free-flowing vehicles are traveling. Conversely, this means that 

only 15 percent of traffic is traveling faster than the 85th percentile speed.

Speed Limit – Speed limit is defined in Section 1A.13 of the Manual on Uniform Traffic Control 

Devices (MUTCD) as “the maximum (or minimum) speed applicable to a section of highway as 

established by law or regulation.” In the United States, there is no longer a national maximum speed 

limit; speed limits are established by State or local governments (FHWA 2009).
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

Speeding – The National Highway Traffic Safety Administration considers a crash to be speedingrelated if any driver in the crash was charged with a speeding-related offense or if a police officer 

indicated that racing, driving too fast for conditions, or exceeding the posted speed limit was 

a contributing factor in the crash. In the context of speed management, speeding is defined as 

exceeding the posted speed limit or driving at a speed that is too fast for conditions.

Target Speed – Target speed is the highest operating speed at which vehicles should ideally operate 

on a roadway in a specific context (ITE 2021). 

Vulnerable Roadway User – The definition of “vulnerable road user,” provided in 23 U.S.C. 

148(a)(15), is a non-motorist—

‘‘(A) with a fatality analysis reporting system person attribute code that is included in the 

definition of the term ‘number of non-motorized fatalities’ in section 490.205 of title 23, 

Code of Federal Regulations (or successor regulations);” or

‘‘(B) described in the term ‘number of non-motorized serious injuries’ in that section.”

The number of non-motorized fatalities as defined by FARS includes pedestrians, bicyclists, 

other cyclists, and persons on personal conveyance.

The Safety in Road Traffic for Vulnerable Users report defines a vulnerable road user as a 

person “unprotected by an outside shield, as they sustain a greater risk of injury in any collision 

witha vehicle and are therefore highly in need of protection against such collisions” (European 

Conference of Ministers of Transport 2000). Throughout this report, people walking, rolling, or 

using other kinds of personal conveyances are referred to as vulnerable road users.
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

EXECUTIVE SUMMARY

Speeding, exceeding the posted speed limits, or traveling too fast for conditions was a contributing 

factor in almost 29 percent of all fatalities in 2021. Of the 42,939 fatalities that occurred on our 

Nation’s roadways that year, 12,330 were speeding-related—an increase of 7.9 percent from 

2020 (Stewart 2023). Speed is fundamental in dictating injury risk for all road users in any crash, 

especially for vulnerable road users (VRUs) such as pedestrians and bicyclists (Corben 2020). 

Studies clearly show that higher speeds result in greater impact at the time of a crash, which leads 

to more severe injuries and fatalities (Elvik 2005; WHO 2008). 

The correlation between speed and injury crashes has been well documented throughout the 

scientific literature on traffic safety, and achieving lower speeds has been proven to save lives and 

reduce serious injuries. To achieve a truly safe transportation system, road safety practitioners 

should not only manage speeds but make achieving safe speeds on all roads a cornerstone of their 

safety policies.

This report will help practitioners understand the impacts of speed on traffic safety and explore 

the link between speed management and the Safe System Approach by introducing a five-stage 

framework on the Safe System Approach for Speed Management. These five stages are establishing 

a vision and building consensus for speed management, collecting, and analyzing speed and 

safety data, prioritizing locations for speed management proactively, selecting speed management 

countermeasures, and conducting ongoing monitoring, evaluation, and adjustment.

The report and Appendix include case studies and examples demonstrating how agencies overcame 

institutional barriers and coalesced on Safe System Approach principles to enact speed management 

programs with measurable reductions in operating speeds and crashes. These case studies include 

examples of successful approaches to lowering speed limits, redesigning roadways, collecting data, 

enforcing speeds with technologies, and working toward network wide realizations of target speeds 

that improve the safety of all road users.

Key themes highlighted in this report from international and domestic documents and interviews 

include the following:

• Strategic plans, like Vision Zero, help build public will for speed management practices, and 

agencies can align those practices with Safe System Approach-based traffic safety goals.

• Speed and safety data are helpful both to guide the speed management program and to build 

public support for the program.

• As much as practicable, agencies should align speed limits and target speeds to prioritize 

injury minimization. This alignment often requires changing the roadway environment to slow 

driver speeds.

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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

1. INTRODUCTION

Speeding, exceeding the posted speed limits, or traveling too fast for conditions was a contributing 

factor in almost 29 percent of all fatalities in 2021. Of the 42,939 fatalities that occurred on our 

Nation’s roadways that year, 12,330 were speeding-related—an increase of 7.9 percent from 

2020 (Stewart 2023). Speed is fundamental in dictating injury risk for all road users in any crash, 

especially for vulnerable road users (VRUs) such as pedestrians and bicyclists (Corben 2020). 

Studies clearly show that higher speeds result in greater impact at the time of a crash, which leads 

to more severe injuries and fatalities (Elvik 2005; WHO 2008).

A nationally consistent approach to speed management can prevent fatalities and serious 

injuries where speeds are high. This report summarizes both international research and results 

from established speed management programs to help inform noteworthy practices for speed 

management in a U.S. context. The recommended approach to speed management is underpinned 

by the Safe System Approach. The Safe System Approach is an internationally recognized best 

practice for reducing and ultimately eliminating fatalities and serious injuries for all road users and 

consists of the following five elements: safe speeds, safe roads, safe vehicles, safe road users, and 

post-crash care. Principles of a Safe System Approach include the following:

• Death and serious injury are unacceptable.

• Humans make mistakes.

• Humans are vulnerable.

• Responsibility for road safety is shared.

• Traffic safety is proactive.

• Redundancy is crucial (for preventing death and serious injury).

The key elements and principles of the Safe System Approach are shown in Figure 1.
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

 Source: Doctor, M., Ngo, C., Ocel, N., Scurry, K., and Shaw, J. (2020). 

 “Safe System – An Approach Toward Zero Traffic Deaths.” FHWA’s Safety 

 Compass Newsletter 14(3), 4-6.

Figure 1. The Safe System Approach.

This report highlights the importance of achieving target speeds and kinetic energy management on 

all roads in a network. Emphasis is placed on the overlap of the safe speeds and safe roads elements 

of the Safe System Approach, as the appropriate target speed for a road depends on the road design, 

roadway context, and desired mix of roadway users. The target speed can be achieved by aligning 

the road design and speed limit with the intended purpose of the roadway while implementing 

speed management countermeasures to reduce operating speeds, as needed. The correlation between 

speeds and injury crashes has been well documented throughout the scientific literature on traffic 

safety, and achieving lower speeds has been proven to save lives and prevent serious injuries. 

Therefore, a Safe System Approach strives to manage speeds so that impact forces experienced 

by road users are not beyond their physical tolerances (Doecke, Kloeden, Dutschke, and 

Baldock 2018).

This informational report will help practitioners understand the impacts of speed on traffic safety 

and make clear the link between speed management and the Safe System Approach by introducing 

a five-stage framework for Safe System Approach for Speed Management. These five stages (shown 

below) are explained in greater detail in Chapter 3.

1 Establishing a vision and building consensus for speed management.

2 Collecting and analyzing speed and safety data.

3 Prioritizing locations for speed management proactively.

4 Selecting speed management countermeasures.

5 Conducting ongoing monitoring, evaluation, and adjustment.
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

The Appendix of this report contains 10 case studies that provide agencies with useful models as to 

how other traffic safety stakeholders have implemented components of the Safe System Approach 

for Speed Management framework. References to these case studies are highlighted with text boxes 

in relevant sections throughout this report.

1.1. The National Roadway Safety Strategy’s Vision for Speed Management

In January 2022, the U.S. Department of Transportation (USDOT) released the first National 

Roadway Safety Strategy (NRSS) to inform priorities and strategies across the entire department 

(USDOT 2022a). This new strategy proclaimed that the USDOT’s priority “is to make our 

transportation system safe for all people.” The Safe System Approach to preventing fatalities and 

serious injuries is foundational to the NRSS. In fact, the strategy lists four key actions (to be led 

by FHWA and NHTSA) that the department will take to work towards the Safe System principle 

of safer speeds, and one of these actions is a robust, multimodal speed management program. To 

achieve safer speeds, “[t]he Department believes it is important to prioritize safety and moving 

individuals at safe speeds over focusing exclusively on the throughput of motor vehicles.” This 

emphasis on safety will require a “multi-faceted approach that leverages road design and other 

infrastructure interventions, speed limit setting, education, and enforcement” (USDOT 2022a). 

The Safe System Approach for Speed Management framework discussed in this report dovetails 

with the multi-faceted speed management approach emphasized by the NRSS.

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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

2. THE RATIONALE FOR A SAFE SYSTEM APPROACH 

FOR SPEED MANAGEMENT

Speed, as is established throughout this chapter’s review of the scientific literature on traffic safety, 

is one of two primary factors that determines whether a crash is fatal or results in a serious injury, 

with vulnerability being the second. Speed directly informs how safe roads are for all roadway 

users. For this reason, speed management is a key component of the NRSS as well as a key element 

of the Safe System Approach. This chapter explores the link between speed and traffic safety by 

highlighting key international and domestic research. It also presents the Safe System Approach 

as a potential strategy for mitigating the harm that high speeds can cause on U.S. roadways. 

Table 1 steps through each element of a Safe System Approach (shown in Figure 1) with a 

detailed explanation of each, a discussion of how they each relate to safe speeds, and links 

to relevant research.

Table 1. Safe System elements and how they relate to safe speeds.

Element Detailed Explanation Connection to Safe Speeds

Safe Speeds Humans are unlikely to survive highspeed crashes. Reducing speeds can 

accommodate human injury tolerances 

in three ways: reducing impact forces, 

providing additional time for drivers to 

stop, and improving drivers’ ability to see 

the surrounding roadway.

The Safe Speeds element is inevitably at 

the heart of a speed program 

(Zia, Harris, and Smith 2019).

Safe Vehicles Vehicles can be designed and regulated 

to minimize the occurrence and severity 

of collisions using safety measures that 

incorporate the latest technology.

Safe vehicle technologies that encourage 

drivers to travel within the speed limit, 

such as Intelligent Speed Adaptation 

(ISA), are available. These tools provide 

drivers with important feedback 

regarding speed limits and operating 

speeds (European Commission 2018).

Safe Road 

Users

The Safe System Approach addresses the 

safety of all road users, including those 

who walk, bike, drive, ride transit, and 

travel by other modes.

This element also highlights the need of 

the transportation system to act equitably 

when it comes to different forms of road 

users (USDOT 2022a).

The system can be designed to 

encourage road users to travel at safe 

speeds. For example, police enforcement 

is often one element of a successful 

speed management program (Turner, 

Khoo, Bosher, and Trumper 2014), 

and immediate safety benefits can be 

achieved through enforcing existing 

speed limits, especially with automated 

technologies.
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

Element Detailed Explanation Connection to Safe Speeds

Safe Roads Designing to accommodate human 

mistakes and injury tolerances can greatly 

reduce the severity of crashes that do 

occur.

Safe roads and safe speeds are two 

elements with a significant connection 

to each other. Speed management 

infrastructure that encourages road 

users to drive at lower speeds is critical 

in creating a long-term safe system.

Post-Crash 

Care

When a person is injured in a collision, 

they rely on emergency first responders to 

quickly locate them, stabilize their injury, 

and transport them to medical facilities. 

Post-crash care also includes forensic 

analysis at the crash site, traffic incident 

management, and other activities.

Consideration should be given to speed 

management infrastructure to reduce 

the time and effort it takes for first 

responders to get to the location of a 

crash. For example, vertical deflection 

devices on emergency services routes 

should be assessed to ensure that 

any safety benefit for road users is 

not outweighed by increases in the 

emergency response times. 

Source: FHWA.

Each section of this chapter explores research related to speed and how it corelates to crashes, speed 

limits, roadway design, and vehicle design. Finally, this chapter presents an overview of speed 

management and explains how it fits within the Safe System Approach.

2.1. Speed and Crashes

Speed is one of the most critical factors in the outcome of motor vehicle crashes. Speed affects a 

driver’s ability to react to other objects on the road, as well as the survivability of road users inside 

and outside of vehicles (National Safety Council 2022). Although speeding-related fatalities in 

the United States (shown in Table 2) steadily declined from 2010 to 2019, 2020 statistics indicate 

that there was a 17 percent increase in speeding-related fatalities, resulting in 11,258 fatalities 

(NHTSA 2022b). NHTSA statistics for 2021 also indicate an additional 7.9 percent increase in 

speeding-related fatalities, for a total of 12,330 such fatalities in 2021 (Stewart 2023). Moreover, 

international estimates indicate that up to 60 percent of roadway fatalities may be speeding-related 

(Soames and Brodie 2022).

However, focusing on speeding alone minimizes the actual impacts of speed itself on traffic safety. 

Speed is one of the determinants of how much kinetic energy is released in a crash (IIHS 2021), 

and years of research and evaluation have shown that it is positively associated with both the 

frequency of crashes and the severity of injuries sustained in those crashes (Elvik 2005; WHO 

2008). Therefore, a singular focus on speeding ignores the impact that even high, legal speeds can 

have on safety, since human injury tolerance can be exceeded even when drivers comply with the 

legal speed limit. Speed management efforts are intended to reduce harmful speeds rather than just 

control speeding behavior. Keeping this in mind, this report focuses on the impacts of speed on 

traffic safety rather than speeding alone.

Table 1. Safe System elements and how they relate to safe speeds. (continued)
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

Table 2. Speeding-related fatalities and injuries in the United States, from 2010 to 2021.

Year

Speeding-Related 

Fatalities

Speeding-Related 

Fatalities as 

Percentage of Total 

Fatalities

Speeding-Related 

Injuries

Speeding-Related 

Injuries as 

Percentage of Total 

Persons Injured

2010 10,508 32% 464,000 21%

2011 10,001 31% 460,000 21%

2012 10,329 31% 503,000 21%

2013 9,696 19% 383,000 17%

2014 9,283 28% 339,000 14%

2015 9,723 27% 348,000 14%

2016 10,291 27% 377,000 12%

2017 9,947 27% 362,000 13%

2018 9,579 26% 359,000 13%

2019 9,478 26% 326,000 12%

2020 11,258 29% 308,013* 13%*

2021 12,330 29% i i

i = injury data unavailable for 2021.

* Estimate

Source: For data up through 2020, see NHTSA. 2022. “Traffic Safety Facts: Speeding.” DOT HS 813 320. Washington, DC: NHTSA. https://

crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/813320. For 2021 data, see T. Stewart. 2023. Overview of Motor Vehicle Traffic Crashes in 2021. 

DOT HS 813 435. Washington, DC: NHTSA.

2.1.1. Human Tolerance to Speed

Humans can physically withstand a limited amount of force if a crash occurs, and this tolerance 

is even more stark if the victims of a crash are young or old. As the speed of a vehicle involved in 

a crash increases, so does the kinetic energy released and the likelihood of the crash resulting in 

a fatality or serious injury. This relationship between speed and safety is especially important for 

roadway users outside of vehicles who cannot rely on vehicle bodies or technologies to protect them.
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

Figure 2 shows probability curves indicating that as impact speed increases, the likelihood of a 

pedestrian being killed or seriously injured also increases (Porter et al. 2021; Tefft 2013). This figure 

shows that crashes occurring at speeds as low as 10 mph can result in serious or fatal injuries for 

pedestrians, while other research shows that crashes at 20 mph can result in serious or fatal injuries 

for people inside motor vehicles (Washington Injury Minimization and Speed Management Policy 

and Guidelines Workgroup 2020). Even these estimates of injury tolerance may be overestimates 

because they do not necessarily account for variations in pedestrian age and physiology or the types 

of vehicles involved. Younger and older pedestrians are likely more susceptible to head injuries in 

crashes (Sandt, Brookshire, Heiny, Blank, and Harmon 2020). One study conducted in North Carolina 

that examined crash and emergency department data determined that nearly one-third of all pedestrian 

crash injuries corresponded to collisions where the vehicle was traveling below or at only 5 mph 

(Harmon, Hancock, Rodgman, Sandt, and Thomas 2021), indicating that roadway environments may 

be unsafe for VRUs even when operating speeds are relatively low.

 Source: Tefft, B. (2013). Impact Speed and a Pedestrian’s Risk of Severe Injury or Death. Accident Analysis & Prevention 50: 871–878. 

Figure 2. Comparison of pedestrian risk curves.

Thankfully, research does indicate that even moderate changes in speed can substantially improve 

safety outcomes for all road users. The World Health Organization (WHO) (2008) highlights this 

effect, showing that a 15 percent reduction in mean speed can decrease the risk of fatal and serious 

injury crashes by almost 50 percent, although this finding is more relevant to higher-speed collisions 

(i.e., those above the curves shown in Figure 2). Etika (2018) reports similar findings, indicating 

that an average speed increase of 0.6 mph will typically result in a 4 to 5 percent increase in the risk 

of a fatality occurring. This increased risk is even more prominent with pedestrians. Peden et al. 

(2004) found that an increase in speed from 19 mph to 31 mph can increase risk of a fatality by 

70 percent for pedestrians. 
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

2.2. Speed Limits and Safety Outcomes

Speed limits and operating speeds are connected, so speed limits are a relevant factor in traffic safety 

outcomes. Agencies must follow the requirement contained in Section 2B.13 of the MUTCD to 

conduct an engineering study when identifying an appropriate non-statutory speed limit for a roadway. 

In this process, agencies collect speed distribution data while noting traffic volumes (including 

pedestrian and bicycle volumes), relevant design elements (e.g., horizontal curvature), placement of 

lighting and traffic control devices, and crash history (Forbes, Gardner, McGee, and Srinivasan 2012). 

Many agencies then place significant weight on the speed distribution data, often setting posted 

speed limits that directly correspond to either the 50th percentile speed or the 85th percentile speed, 

depending on State and local legislation and practices. Many States and jurisdictions legally require 

the use of the 85th percentile speed for posted speed limit setting.

However, the 85th percentile speed may not correspond to safe operations for every roadway 

context. Drivers often underestimate their own travel speeds by 10 percent at higher speeds (e.g., 

70 mph) and 30 percent at lower speeds (e.g., 35 mph), resulting in operating speeds higher than 

posted speed limits that are potentially unsafe (Grembek et al. 2020). The 85th percentile approach 

may also not account for additional considerations, such as crash experience, road characteristics, 

road context, and presence of pedestrians and bicyclists. Setting context appropriate speed limits is a 

key part of the Safe System Approach for Speed Management framework.

2.2.1. Setting Safer Speed Limits

Much of the current surface transportation system in both the United States and abroad was not 

designed with human injury tolerance in mind (Peden et al. 2004). In other words, the current 

system produces speeds that may not be safe for all road users. International researchers and road 

agencies have identified potential injury minimization speed limits that are more likely to prevent 

fatalities and serious injuries. These speed limits, like those highlighted by Jurewicz and Turner 

(2010) and shown in Table 3, vary by roadway classification but are rooted in the Safe System 

Approach. Other research has demonstrated that changing speed limits can achieve a 4 mph 

reduction in 85th percentile speed and 25 percent reduction in casualty crashes on average (Hillier, 

Makwasha, and Turner 2016). This has been shown in other literature to vary greatly depending on 

the speed environment and levels of enforcement.

An analysis of speed limit evaluation studies showed that lowering the speed limit on high-speed 

roads has a greater effect on mean operating speeds than lowering the speed limits on low-speed 

roads (even for the same reduction in speed limit) (Jurewicz and Hall 2009). However, even 

changes in lower speed environments can produce safety benefits, especially for vulnerable road 

users. For example, a 6.2 mph speed limit reduction may reduce mean operating speeds on average 

by approximately 2.5 mph (Jurewicz and Hall 2009). Table 4 summarizes these documented safety 

benefits corresponding to speed limit changes. This international research demonstrates that if speed 

limits are proactively lowered to address safety risks and implemented alongside speed management 

treatments, practitioners can expect that operating speeds and crash frequencies will decrease.
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

Table 3. Example of a proposed safer speed limit model in the Netherlands, 

alongside the existing general speed limits.

Roadway Context

General Speed 

Limits in the 

Netherlands

Safer Speed 

Limit to Minimize 

Injuries

Single-lane rural road (likely only run-off-road collisions) 62 to 75 mph 75 mph

Rural collector with no pedestrian or bicyclist activity and 

physical separation between driving directions 62 mph 50 mph

Rural collector with no pedestrian or bicyclist activity but 

no physical separation between driving directions 50 mph 43 mph

Rural access road 37–50 mph 25–50 mph

Intersections on rural collectors with pedestrian and 

bicyclist activity 37 mph 19 mph

Intersections on rural collectors without pedestrian and 

bicyclist activity 50 mph 31 mph

Urban arterial 43 mph 43 mph

Urban collector 31 mph 31 mph

Urban local road 19 to 31 mph 19 mph

Intersection on urban collector 31 mph 31 mph

Intersection on urban local road 19 to 31 mph 19 mph

Pedestrian and bicyclist crossing - 19 mph

General context when head-on-crashes are possible - 43 mph

General context when side impact crashes are possible - 19 mph

- No data.

Source: C. Jurewicz and B. Turner. (2010). Infrastructure/Speed Limit Relationship in Relation to Road Safety Outcomes. Sydney, New South Wales: 

Austroads.
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

Table 4. Summary of speed and crash study results.

Reference Country

Speed Limit 

Reduction

Mean 

Speed 

Change Crash Reductions

Finch et al. (1994) Switzerland 81 to 75 mph 3 mph Fatal crashes −12%

Sliogeris (1992) cited 

in Patterson et al. 

(2002)

Australia 68 to 62 mph 

rural freeways

- Injury crashes −19%

Nilsson (1990) cited in 

Stuster et al. (1998)

Sweden 68 to 56 mph 9 mph Fatal crashes −21%

Peltola (1991) cited in 

Stuster et al. (1998)

UK 62 to 50 mph 2 mph Crashes −14%

Frith and Toomath 

(1982) cited by 

Patterson et al. (2000)

New Zealand 55 or 60 to 

50 mph

rural* default

8−10 mph Fatalities −37%;

Serious injuries −24%; 

Minor injuries −22%*

Engel and Thomsen 

(1988) cited in 

Cameron and Elvik 

(2008)

Denmark 37 to 31 mph 

urban default

2–3 mph Fatalities −24% 

Serious Injuries −7% 

Minor Injuries −11%

Scharping (1994) cited 

in Stuster et al. (1998)

Germany 37 to 31 mph - Crashes −20%

Hoareau, Newstead, 

and Cameron (2006) 

cited in Cameron and 

Elvik (2008)

Australia 

(Victoria)

37 to 31 mph 

local roads

1–2 mph Fatal crashes −21%; 

Serious injury crashes −3%;

Minor injury crashes −16%; 

Casualty crashes−12%;

Pedestrian fatal crashes −25%; 

Pedestrian serious injury crashes −40%

Kloeden, Woolley, and 

McLean (2007) cited 

in Cameron and Elvik 

(2008)

Australia 

(South 

Australia)

37 to 31 mph 

local roads

2.4 mph Fatalities −40%;

Serious injuries −20%;

Minor injuries −23 to −26%; 

Casualty crashes −20%

Walsh and Smith 

(1999) cited in Archer 

et al. (2008)

Australia 

(Queensland)

37 to 31 mph 

local roads

3 mph Fatal crashes −88%;

Casualty crashes −23%

Hoareau and 

Newstead (2004) cited 

in Archer et al. (2008)

Australia 

(Western 

Australia)

37 to 31 mph

local roads

0.6 mph Casualty crashes −21%; 

Pedestrian casualty crashes−51%

Green, Gunatillake, 

and Styles (2003) cited 

in Archer et al. (2008)

Australia 

(ACT)

37 to 31 mph 

local roads

- All crashes −2.1% 

(not significant)

Hu and Cicchino 

2020)

Boston, 

U.S.A.

30 to 25 mph 0.3% 

decrease

-

- No data.

*For reference, urban areas experienced reductions of 15%, 9%, and 4% respectively over the same period.

Source: FHWA.
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

2.2.2. The Importance of Reviewing Speed Limits

The basis of any speed management approach should be the setting of speed limits. As 

demonstrated in Table 4, research demonstrates that a proactive approach to reviewing and 

then lowering speed limits, if appropriate, can produce significant safety benefits (Jurewicz and 

Turner 2010).

Although it is often desirable to implement infrastructure changes to reduce serious crash risks, 

this might not be easily achieved at a network level and could require significant time, resources, 

and funding to accomplish. Therefore, some agencies begin with a proactive evaluation of speed 

limits and lower those that correspond to the greatest risk in the roadway network. The power 

of speed limit changes is that they can be implemented much faster and at a far greater scale 

than transformational infrastructure changes. One proactive approach to speed limit setting, the 

Infrastructure Risk Rating (IRR) model (Zia, Harris, and Smith 2019), has been demonstrated to 

produce changes in both mean operating speeds and reductions in crashes. Research also shows that 

while speed limit lowering does impact travel time, a key concern for road users when it comes to 

speed change, the effect is often minor (Waka Kotahi 2022). These points combined make speed 

limit changes a key consideration when wanting to make a transformational change to the risk 

across a large network within a reasonable time.

2.2.3. International Speed Limit Practices

International traffic agencies have implemented speed limit changes in coordination with 

infrastructure and planning changes as part of a Safe System type framework to manage speeds and 

improve traffic safety. Some example programs include the following:

• Sustainable Safety in the Netherlands: As part of the Dutch Sustainable Safety approach, 

practitioners carefully examined roadway functional classification and developed strict 

criteria for speed limit setting alongside operational and design considerations. In the 

Netherlands, certain rules were determined to limit potentially fatal conflicts for several 

different scenarios. These include strict speed limits (e.g., 50 mph for rural distributor 

roads), separated bike lanes for urban distributor roads with 31 mph speed limits, and 

lower speed limits (i.e., speed limits below 31 mph) when separation cannot be provided 

for bicyclists. From 1998 through 2007 it is estimated that more than 25,476 miles of 

19 mph speed limits and more than 20,505 miles of 37 mph speed limits were 

implemented in the Netherlands (often with supporting infrastructure). After this 

implementation, around 70 percent of urban roads had a speed limit of 19 mph and almost 

60 percent of all rural roads had a speed limit of 37 mph. The consistent lowering of 

speeds was achieved through almost all road authorities designing a categorization plan 

for roads on their road network. Together with a range of other road safety infrastructure 

improvements, these measures prevented an estimated 120 to 145 fatalities per year 

(Weijermars and Wegman 2011).
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

• Slow-Speed Zones: Some international agencies have implemented slow-speed zones 

to address risk of traffic injury with a combination of speed limits and physical design 

measures. In this speed management approach, agencies set target speeds of 20 mph or lower 

within a designated area (e.g., a residential area between major arterials) rather than on a 

single roadway. Agencies then alter design features within this area to ensure consistent, 

self-enforcing roadways. Designating slow-speed zones rather than making piecemeal 

modifications to roadway segments has been demonstrated to be more effective than urban 

slow-speed zones without self-enforcing roadway designs. An analysis of 20 mph zones in 

London found a 46 percent reduction in fatal and serious injury crashes overall (Sharpin et al. 

2021). In 2011, Japan introduced 19 mph zones. Over 1,100 of these zones were implemented 

by the end of March 2014, and these are being complimented by new zones with even lower 

speed limits. Analysis of large towns in Japan found that many have gone an entire year 

without a single fatality. While this may not be due to Safe System policies in isolation, these 

zones do show that becoming a genuine “zero deaths” city is possible (ITF 2016).

2.3. Speed and Roadway Design

Previous sections illustrated the link between speed limits, operating speeds, and safety. Speed is 

also connected to roadway design, both as a design element for specific geometric features of a 

roadway (e.g., curve radii) and as an operational characteristic of the roadway that can be influenced 

by additional design elements, like roadside features (AASHTO 2018). Designing roadways using 

higher design speeds can cue drivers that higher operating speeds are appropriate, even if posted 

speed limits are lower than design speeds.

Rsearch has demonstrated that non-access-controlled roadway environments that provide visual 

friction or “hem in” drivers can induce lower speeds. Roadside features that produce visual friction, 

like on-street parking, sidewalks, or downtown locations, are associated with lower speeds, while 

roadways with wide shoulders, large building setbacks, and residential-type land development were 

associated with higher speeds (Ivan, Garrick, and Hanson 2009). Creating visual friction through 

roadside design can be an effective way to slow traffic, particularly on low-speed roadways with 

pedestrian and bicyclist activity. On higher speed, access-controlled facilities, agencies should ensure 

that curves can be navigated safely and may consider roadside designs that minimize the severity of 

run-off-road crashes by referring to the AASHTO Roadside Design Guide (AASHTO 2011).

AASHTO’s A Policy on Geometric Design of Highways and Streets (aka, the Green Book) also 

affords some flexibility when specifying roadway cross-sectional elements in relation to the design 

speed and the context of the facility. In the 7th Edition of the Green Book, AASHTO notes: “[o]n 

lower-speed facilities, use of above-minimum design criteria may encourage travel at speeds higher 

than the design speed” (AASHTO 2018). Infrastructure owners and operators may design narrower 

cross-sections to maintain visual friction and restrict speeding behavior where appropriate for the 

context. AASHTO provides flexibility for the use of 10 or 11 ft lanes to accommodate lower speeds 

in urban environments. AASHTO also encourages roadway designers to select a target speed when 

roads are designed for walkable or mixed-use urban environments, with the target speed equal to 

the highest speed appropriate to provide a safe and comfortable environment for multimodal use 

(AASHTO 2018).
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

2.4. Speed and Vehicle Design

It is also worth noting that vehicle designs have changed substantially over the years, resulting in 

generally larger and heavier vehicles that are also capable of greater acceleration and speed than those 

in decades past. Sport utility vehicles (SUVs) now compose a greater proportion of the U.S. vehicle 

fleet (IIHS 2020), and notwithstanding increases in protection of vehicle occupants, pedestrians and 

bicyclists are likely at greater risk as a result of these vehicle fleet changes. Both the increased speed 

and mass of these larger vehicles correspond to higher likelihoods of people being killed or seriously 

injured in crashes, especially those outside vehicles. Research shows that while injury outcomes 

remained relatively similar between vehicle groups at low speeds (lower energy) and at high speeds 

(typically fatal crash injuries), there was an elevated risk of injury for pedestrians at medium speeds 

(greater than 19 mph) due to SUV design (Monfort and Mueller 2020).

2.5. Speed and the Safe System Approach

The Safe System Approach lies at the core of the NRSS (USDOT 2022). This approach represents 

a paradigm shift in that it recognizes road safety as a shared responsibility. It acknowledges 

that humans are vulnerable and make mistakes, so it is critical for all responsible traffic safety 

practitioners to recognize that death and serious injuries are unacceptable and to proactively build 

in redundancies to the surface transportation system. This revised emphasis is important because of 

the following:

• Blaming individuals after incidents occur, often due to distraction or human mistakes that all 

drivers make, does not address the underlining risk that exists for future crashes to occur.

• Instead, the road system should be more human-centric and allow for reasonable human 

mistakes without those mistakes resulting in fatalities or serious injuries.

• Aligning speed limits to higher operating speeds presumes that most drivers can correctly 

interpret a road environment and select a safe operating speed. This is not always the case. 

Roadways are often designed in ways that facilitate high speeds, and humans are often not 

cognizant of the risks posed by high speeds. It is not realistic to assume that drivers can 

determine safe speeds within mere moments of entering a new road environment. For example, 

in a rural environment, drivers will often misjudge the correct speed to navigate curves, 

especially curves that are out of context (i.e., require a large speed change to safely negotiate) 

and intersections, even where they have priority.
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

2.6. Integrating Speed Management and Systemic Safety in the Safe System 

Approach

Vision Zero was the origin of several countries’ shifts toward the Safe System Approach after 

Tingvall and Haworth (1999) and the Swedish Road Administration (2006) established that there 

is an ethical basis for prioritizing safety above all else. This ethical mandate has served as the 

foundation for speed management activities intended to prevent all deaths and serious injuries on 

various countries’ roadways. An important demonstration of this Safe System based approach to 

speed management is that implemented in Auckland, New Zealand. In 2016, the Waka Kotahi 

New Zealand Transportation Agency published the New Zealand Speed Management Guide. This 

guide created a framework for implementing target speeds and demonstrated the benefit that can be 

achieved through unified action under a Safe System vision. The guide also heavily influenced the 

steps laid out in this informational report.

 See Appendix A.8. to see how Auckland implemented New Zealand’s influential Speed 

Management Guide.

2.6.1. Overview of Speed Management Practices

Speed management is, generally, an approach to meeting safe speeds. Speed management may entail 

changes to speed limits, changes to roadway designs (e.g., intentionally designing narrower lanes on a 

roadway to slow traffic), use of traffic control to maintain desired speeds, and the use of enforcement, 

signs, and technology to increase compliance with speed limits and to provide feedback to drivers 

about desirable operating speeds. When selecting appropriate speed management techniques, it 

may be helpful to consider the roadway setting, purpose of the roadway, traffic composition, and 

desired pedestrian and bicyclist activity, alongside budgetary constraints (FHWA 2017a). Readers are 

encouraged to visit FHWA’s Speed Management Safety webpage to access additional resources for 

selecting and implementing different speed management countermeasures (FHWA 2017b). FHWA 

and ITE (2017) developed a Traffic Calming ePrimer that contains a module entitled “Toolbox 

of Individual Traffic Calming Measures.” This module provides guidance on implementing traffic 

calming treatments, including the following:

• Lateral shifts

• Chicanes

• Realigned intersections

• Traffic circles

• Roundabouts

• Speed humps

• Speed cushions

• Speed tables

• Raised crosswalks

• Raised intersections

• Corner extensions/bulb-outs

• Chokers

• Median islands

• On-street parking

• Road diets

• Diagonal diverters

• Road closures

• Median barriers and forced-turn islands
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

The FHWA has also published a report titled Noteworthy Speed Management Practices (Hawkins 

and Hallmark 2020). In this report, Hawkins and Hallmark highlight exemplary speed management 

approaches and the various elements they combined. Some critical practices for successful speed 

management programs include the following:

• It is valuable to develop a speed management program integrated with a vision for public 

health (e.g., Vision Zero).

• It is valuable to set indicators of success and collect relevant data.

• Speed limits should be credible and should align with the roadway context.

• Countermeasures can be combined to produce comprehensive speed management.

2.6.2. Traffic Safety Management and Analytical Frameworks

Many roadway agencies in the United States use a six-step traffic safety management process to 

identify locations for treatment to improve safety. A variation of this approach, called the systemic 

safety approach, is compatible with the Safe System Approach. The systemic safety approach 

follows six steps, including the following (Preston, Storm, Bennett, and Wemple 2013):

1. Identify focus crash types and risk factors.

2. Screen and prioritize candidate locations.

3. Select countermeasures.

4. Prioritize projects.

5. Identify funding for systemic program and implement.

6. Perform system program evaluation.

Some traffic safety agencies have also implemented systemic approaches to speed management. 

These approaches include reviewing and implementing speed limits over areas rather than just on 

one or two roads at a time. European area-wide road safety management programs have shown 

significant crash and injury reductions ranging from 15 to 80 percent (WHO 2004). Eventually, the 

aim should be to have all speed limits on every road within the network aligned to the same speed 

management framework. By treating the entire network, agencies can achieve the greatest reduction 

in fatalities and serious injuries. Additionally, inconsistent application of Safe System-aligned 

speeds and roadway designs may lead to road user confusion.

Internationally, agencies have more explicitly tied the Safe System Approach to speed management 

practices. For example, Jurewicz (2009) explicitly envisions a Safe System analysis as a key 

decision point for determining which speed management techniques are needed to achieve a “harm 

minimization speed” (or a “target speed” in the U.S. context). In this framework, agencies follow a 

four-step process for speed limit setting within a Safe System Approach:

• First, the agency determines what the posted speed limit of a roadway should be based on its 

functional purpose.

• Second, the target speed that may be appropriate for the functional classification and posted 

speed limit are identified.
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

• Following this step, the agency analyzes the roadway using Safe System Approach principles 

to determine whether the current roadway design facilitates the target speed of the roadway.

• Finally, the agency selects speed management measures to align the roadway design with the 

target speed (Jurewicz 2009).

One analytical framework used by some Safe System practitioners to align roadway design with 

target speed is the concept of “Movement and Place.” Movement refers to the mobility provided 

to different modes of travel at a location, and place refers to the activity level desired at a location. 

High “place” areas have a high level of VRU activity and are key destinations for people. Corben 

(2020) emphasizes that the injury minimization speed for pedestrians and bicyclists is 19 mph, so 

target speeds in high “place” areas should be based on this threshold. Examples include central city 

zones and major (commercial) activity centers. “Movement” is a function of road hierarchy and the 

traffic demand for a route. Many high-risk routes within cities are a result of a conflict between a 

medium to high place function and medium to high movement functions. These are often referred to 

as mixed-use arterials (Corben 2020).

The Movement and Place framework is similar to, but differs from, the concepts of mobility and 

access often used in determining the function of roadways in the United States. International 

agencies have applied the Movement and Place framework as an analytical lens for identifying 

risks within a roadway network that then can be treated proactively. Considering the feasibility of a 

location to serve as a place allows practitioners to frame roadway design in terms of who could use 

a location safely and comfortably. As the movement afforded by a location increases, its capacity to 

serve as a place typically decreases, but this is not a linear relationship (Corben 2020).

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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

3. THE SAFE SYSTEM APPROACH FOR 

SPEED MANAGEMENT

Speed is directly linked to the severity of traffic crashes. Given the high incidence of speedingrelated fatalities in the United States, and the strategic emphasis on speed management in the 

NRSS, a new, Safe System-based approach to speed management may support agencies’ efforts to 

prevent traffic fatalities and serious injuries by proactively producing target speeds on the roadway 

network. This chapter outlines a new Safe System Approach for Speed Management framework. 

The proposed framework (Figure 3) is a high-level process that has been constructed from a range 

of different case studies and informed by the research literature cited throughout Chapter 2; readers 

are encouraged to read the case studies presented in the Appendix to see specific applications of 

concepts and principles. Subsections in this chapter correspond to each of the five stages of the 

framework shown in Figure 3. While these stages are presented here as a cyclical process, agencies 

may be at different stages of implementation and may need to revisit earlier or later stages of 

the process as they evaluate their speed and safety outcomes. This framework is also intended to 

encompass actions taken by both State and local agencies, but the specific countermeasures and 

coalition building jurisdictions use to achieve target speeds may vary.

 Source: FHWA.

Figure 3. The Safe System Approach for Speed Management Framework.
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

Establishing a Vision and Building Consensus for Speed Management

This section introduces topics relevant to transportation agencies seeking to establish a new 

Safe System-based speed management program. These topics include examining institutional 

mechanisms, leveraging community support, embedding the Safe System Approach into 

organizational policies and plans, and adopting a strategic framework.

A key idea discussed throughout this section is the identification and understanding of potential policy 

barriers, various methods to compensate or overcome these barriers, as well as institutional mechanisms 

for implementation. This section contains discussion of speed management strategies for agencies that 

can easily change speed limits as well as those that cannot. The following case studies also demonstrate 

how agencies can establish a vision and build consensus for speed management:

• Case Study A.1. Washington State Injury Minimization and Speed Management— 

Washington State, USA

• Case Study A.3. 2020 Vision Zero: Speed Management—Fremont, California, USA

• Case Study A.6. Multi-disciplinary Approach for Speed Reduction Citywide—Portland, 

Oregon, USA

Collecting and Analyzing Speed and Safety Data

This section lists the different types of data that can be used to identify speed problems on a 

network. It also discusses the different types of data and their sources and limitations. The Safe 

System Approach for Speed Management framework should be a data-informed approach that can 

leverage clear information to help enforce the vision for speed management while also supporting 

ongoing evaluation efforts, especially if interim goals are set on the way to achieving target speeds.

Relevant case studies for this topic include the following:

• Case Study A.2. Video-Based Network-Wide Speed and Speeding Analysis—Bellevue, 

Washington, USA

• Case Study A.7. Seattle Systemic Speed Limit Reduction—Seattle, Washington, USA

Prioritizing Locations for Speed Management Proactively

This section describes the process of applying different methods for identifying treatment locations. 

These methods include systemic analyses, a placemaking framework, and equity considerations. 

The Safe System Approach for Speed Management framework recognizes that sometimes the 

entire network cannot be targeted simultaneously, meaning that areas within the network must 

be prioritized over others. Agencies may consider employing Highway Safety Manual (HSM) 

(AASHTO 2010) methods for using crash data to apply safety performance functions and Empirical 

Bayes adjustments for determining estimated crashes in a systemic process. This will enable 

agencies to proactively identify locations where the risk of a serious or fatal crash is high (Preston, 

Storm, Bennett, and Wemple 2013). It may be beneficial to target specific segments with major 

speed problems or where fatal and injury crashes can be most reduced first while building support 

for more widespread systemic improvements.
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

Relevant case studies for this topic include the following:

• Case Study A.6. Multi-Disciplinary Approach for Speed Reduction Citywide—Portland, 

Oregon, USA

• Case Study A.9. Network-Wide Speed Limit Reduction—Mornington Peninsula, Australia

Selecting Speed Management Countermeasures

This section includes the different approaches agencies take to treating speed problems at the 

locations identified in the previous step while moving toward systemic achievement of target 

speeds. Implementation in a Safe System Approach for Speed Management framework includes 

both infrastructure changes and speed limit changes (where possible). Speed limit changes can be 

controversial, but other countermeasures, including traffic calming and feedback signs, can reduce 

operating speeds, making them closer to target speeds while agencies build support for lowering 

speed limits. It is important to adequately consider which kinds of roads will require supporting 

infrastructure and when speed management projects can be implemented in relation to speed limits.

Relevant case studies for this topic include the following:

• Case Study A.5. New York City’s Speeding Solutions Toolkit—New York City, New York, USA

• Case Study A.10. Speed Limit Reduction on Urban Roads—Republic of Korea

Ongoing Monitoring, Evaluation, and Adjustment

The final section of the Safe System Approach for Speed Management framework refers to the 

many interrelated steps that can be taken to move operating speeds on a roadway network closer 

to target speeds. Monitoring helps inform better decision making for future speed limit programs 

and helps to determine locations where additional interventions may be required to achieve 

target speeds. This includes locations that require additional enforcement, infrastructure, or other 

supporting initiatives. The results also help communicate to the public why speed management 

programs are being undertaken and dispel some of the myths surrounding them.

Relevant case studies include the following:

• Case Study A.4. Automated Speed Enforcement—Montgomery County, Maryland, USA

3.1. Establishing a Vision and Building Consensus for Speed Management

Although speed management programs have the potential to substantially improve safety for all 

road users, speed management activities are often polarizing and may entail publicly perceived 

compromises in vehicular throughput or mobility. Therefore, the first step in developing an effective, 

Safe System Approach-based speed management program is to create community support in a 

jurisdictional vision for target speeds. Creating this vision may entail multiple steps, including the 

following:

1. Examining the existing legal constraints and sociopolitical factors in your jurisdiction.

2. Determining the practical scope of speed management activities.

3. Identifying appropriate speed management activities for your agency.
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

This section presents information for both State and local agencies. The relationships between State, 

county, and city DOTs vary from State to State, so not all speed management activities highlighted 

may be possible for all agencies. As mentioned, this section presents potential steps for agencies 

able to set lower speed limits as well as those for whom speed limit setting is regulated legislatively.

3.1.1. Examine the Existing Legal Constraints and Sociopolitical Factors in 

Your Jurisdiction

Agencies seeking to create a vision for a Safe System-based speed management program may start 

with a thorough understanding of the current speed limit laws that govern posted and statutory 

speed limits in their jurisdictions. City agencies may also need to examine ownership of the 

local road network to determine which roads are within their jurisdiction and would therefore be 

candidates for a speed management program. State DOTs may have more flexibility for changing 

posted speed limits, but governing legislation varies from State to State.

State and local ordinances for road design and signing may impact the process of changing speed 

limits. Statutory speed limit changes require legislative action and are therefore beyond the scope 

of this report. However, State DOTs can adopt policies that can influence the ways in which local 

agencies design roads and post speed limits. For example, changes to local policies and ordinances 

may enable local agencies to implement road diets or otherwise modify locally owned roads to align 

operating speeds closely with target speeds.

In the Washington State Injury Minimization and Speed Management Policy Elements and 

Implementation Recommendations, the authors draw attention to the fact that local agencies may 

be bound by their local code to follow the International Fire Code (IFC) and require a 28-ft street 

with parking on both sides. This type of roadway may provide minimal visual friction and could 

induce higher operating speeds, so local agencies may need exemptions to local codes to avoid 

designing these types of roadways. Policies providing these kinds of exemptions could be part of a 

speed management program (Washington Injury Minimization and Speed Management Policy and 

Guidelines Workgroup 2020).

3.1.2. Determining the Practical Scope of Speed Management Activities

After identifying important factors that influence the ability to adjust speed limits within 

a jurisdiction, the next step is to consider the practical scope and extent of possible speed 

management programs. If speed limits can be changed, it may be helpful to:

• Identify applicable road segments for speed limit change.

• Identify appropriate target speeds for roadway designs.
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

Identify applicable road segments for speed limit change: When determining where speed limits 

can be changed, agencies should seek to answer several related questions:

• Who owns this roadway?

• What speed limit is posted on this roadway?

• Where are speed limit signs located on this roadway?

• Are there any applications for slow-speed zones on this roadway?

• What design features may need to be changed to accommodate a speed limit change?

Considering these questions beforehand may aid with subsequent stages of the Safe System Approach for 

Speed Management framework, namely the “prioritizing locations” step to identify sites for treatment. 

Jurisdictions will see the greatest safety benefits if all roads within a network are aligned with that 

jurisdiction’s speed management goals (WHO 2004), but some agencies may need to prioritize specific 

roadways first to build public support for using target speeds on all roads under the agency’s jurisdiction. 

Some agencies may have limited potential to make changes on State owned roadways within their 

jurisdiction, for example, so focusing on locally owned arterials at this stage may simplify the prioritization 

process later. Identifying applicable slow-speed zone locations may also aid in prioritization later.

Urban cores and school zones are often the most applicable locations in the United States for the 

implementations of wide-scale speed management efforts (see Sharpin et al. 2021 for some common 

applications), but some cities have also found success implementing shared streets programs in 

other contexts. These programs—sometimes called “partial street closures”, “healthy streets”, “play 

streets”, “bike boulevards”, and “neighborhood greenways”—can include a variety of different 

countermeasures and geometric designs but typically entail community outreach and often feature 

intensive traffic calming treatments. Agencies seeking to apply lessons learned from shared streets 

programs may find success by installing new pedestrian and bicycle facilities (often through road diets 

to reconfigure existing travel lanes), combining partial street closures with traffic calming devices, 

reallocating on-street parking as curb space, and reducing speed limits to make roadways safer for 

VRUs (Combs and Pardo 2021; Combs et al. 2020).

Highlighting successfully implemented slow-speed zones can be a first step to demonstrating the 

efficacy of Safe System-based speed management efforts. Successes with slow-speed zones can 

build public support for more projects while demonstrating that the implementing agency is directly 

improving the safety of all road users. These early successes can help build motivation for broader 

systemic speed management programs.

Identify appropriate target speeds for roadway designs: The goal of the Safe System Approach 

for Speed Management framework is to enable agencies to match operating speeds with target speeds 

along corridors to prevent fatalities and serious injuries. To the extent possible, attaining target speeds 

on a roadway should be considered the end goal of speed limit adjustments. However, drivers may 

not immediately respond to changes in speed limit, especially if corresponding infrastructure designs 

are not also implemented. Therefore, it may be necessary to implement roadway redesigns and adjust 

speed limits incrementally while measuring changes in mean speeds and building public support for 

the target speeds. It may also be necessary to adjust target speeds if ongoing data collection reveals 

that safety goals (e.g., prevention of fatal crashes) have not yet been met, or if safety problems have 

migrated to different locations along a corridor or network.
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

There are a variety of resources available that may assist agencies in identifying target speeds. 

One method that agencies can use is to base target speeds on driver speeds that correspond to a low 

(i.e., 10 percent or less) chance of a fatal or serious injury occurring. To apply this method, agencies 

may identify target crash types for prevention as part of a strategic program (see the discussion 

of Highway Safety Improvement Plans in Section 3.1.3) and then implement speed management 

countermeasures to reduce the speeds that produce fatal or serious injuries in those crash types. See 

Table 5 for example crash types, driver speeds, and target speeds. For crash types involving two 

vehicles, the mass and speed of each vehicle is assumed to be identical (Jurewicz, Sobhani, Woolley, 

Dutschke, and Corben 2016; Doecke, Kloeden, Dutschke, and Baldock 2018).

Table 5. Probability of fatality or serious injury corresponding to different crash types.

Crash Type

Driver Speeds Corresponding to 10% Fatal Injury 

Risk and 10% Serious Injury Risk

Pedestrian/vehicle crashi 20 mph for fatality

10 mph for serious injury

Side impact vehicle/vehicle crash 

(typically at intersections)i

30 mph for fatality

20 mph for serious injury

Head-on vehicle/vehicle crash 

(typically without median barriers)i

30–45 mph for fatality 

20 mph for serious injury

Rear-end vehicle/vehicle crashi 35–70 mph for fatality 

35 mph for serious injury

Motorcycle crashii 19 mph for fatality

i = synthesized by Washington Injury Minimization and Speed Management Policy and Guidelines Workgroup, 2020.

ii = reported as biomechanical tolerance in Gaca and Pazdan 2017; see also Fildes, Langford, Andrea, and Scully 2005.

Another target speed method adopted by some State DOTs is to specify the highest speed at which 

drivers should operate on a road based on the roadway context, multimodal traffic generated by 

adjacent development, and potential risks to VRUs. These agencies then set design speeds as close to 

those target speeds as feasible. For example, Florida DOT (FDOT) lists target speeds in its Roadway 

Design Manual for different context classifications, as well as speed management techniques that 

can be used in retrofits or new designs to achieve those target speeds (Table 6) (FDOT 2022). The 

Florida design manual provides target speeds ranging from less than 25 mph to 45 mph on roads in 

rural towns, dependent on design features; if the desired safe operating speed in a rural town is 40 

mph, the design manual states that agencies may consider installing roundabouts, lane narrowing, and 

more (FDOT 2022). FDOT recognizes that target speeds are highly context-sensitive and may require 

incremental changes to roadway design and speed limits to achieve results. However, the exemplified 

speed management strategies demonstrate that establishing target speeds is an important step to 

determining the most appropriate design features to ensure safe operations on a road.
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

Table 6. FDOT Design Manual target speeds and speed management techniques.

Area Type Context Classification

Target 

Speed 

(mph) Strategies

Rural C1-Natural (natural 

or wilderness lands)

55–70 N/A: Speed Management Strategies are not 

used on high-speed roadways

Rural C2-Rural sparsely 

settled)

55–70 N/A: Speed Management Strategies are not 

used on high-speed roadways

Rural C2T-Rural Town 

(small concentrations 

of developed areas 

surround by natural 

areas)

40–45 Roundabout, Lane Narrowing, Horizontal 

Deflection, Speed Feedback Signs, Rectangular 

Rapid Flashing Beacons (RRFB) and Pedestrian 

Hybrid Beacons (PHB)

35 Techniques for 40–45 mph, plus 

On- street Parking, Street Trees, Short 

Blocks, Islands at Crossings, Road Diet, 

Bulb-outs,Terminated Vista

30 Techniques for 35–45 mph, plus Chicanes, 

Islands in curved sections

≤ 25 Techniques for 30–45 mph, plus Vertical 

Deflection

Suburban C3R-Suburban 

(mostly residential 

within large blocks), 

C3C-Suburban 

Commercial (mostly 

non-residential 

with large building 

footprints)

50–55 Project-specific

40–45 Roundabout, Lane Narrowing, Horizontal 

Deflection, Speed Feedback Signs, RRFB and 

PHB

35 Roundabout, Lane Narrowing, Horizontal 

Deflection, Speed Feedback Signs, Islands 

in crossings, Road Diet, RRFB and PHB, 

Terminated Vista

Urban C4-Urban general 

(mixed uses within 

small blocks)

40–45 Roundabout, Lane Narrowing, Horizontal 

Deflection, Speed Feedback Signs, RRFB and 

PHB

35 Techniques for 40–45 mph plus On-Street 

Parking, Street Trees, Short Blocks, Islands at 

Crossings, Bulb-outs, Terminated Vista, Road 

Diet

30 Techniques for 35–45 mph plus Chicanes, 

Islands in Curve Sections
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

Area Type Context Classification

Target 

Speed 

(mph) Strategies

Urban C5-Urban Center 

(missed uses within 

small blocks, 

typically concentrated 

around a few blocks)

35 Roundabout, On-street Parking, Street Trees, 

Short Blocks, Speed Feedback Signs, Islands 

in Crossings, Road Diet, Bulb-outs, RRFB and 

HAWK, Terminated Vista

30 Techniques for 35 mph plus Chicanes, Island in 

Curve Sections

25 Techniques for 30–35 mph plus Vertical 

Deflection

Urban C6-Urban Core (areas 

with highest density)

30 Roundabout, On-Street Parking, Horizontal 

Deflection, Street Trees, Islands in Curve 

Sections, Road Diet, Bulb-outs, Terminated 

Vista

25 Techniques for 30 mph plus vertical deflection

Source: FDOT. (2022). FDOT Design Manual: Development and Processes. Tallahassee, FL: Florida Department of Transportation.

Regardless of whether an agency has the capacity to change speed limits, a Safe System 

Approach for Speed Management framework could include roadway modifications and traffic 

calming efforts. Although lowering speed limits may be effective at reducing mean speeds 

(see Table 4 in Chapter 2), speed limit changes alone are unlikely to produce target speeds. 

Therefore, agencies seeking to achieve target speeds through a Safe System Approach should 

consider prioritizing the roadway modification components of a speed management program 

while also lowering speed limits.

3.1.3. Establishing a Vision for Speed Management: Mechanisms for State Agencies

State DOTs and other State-level traffic safety stakeholders (including legislative bodies) are wellpositioned to meaningfully shape a vision for speed management through unique levers, including 

the following:

• State transportation policies or Executive Orders

• Strategic plans

• Roadway design manuals

Not every State agency has access to all potential measures that can be implemented through a 

speed management program, so agencies seeking to adopt the Safe System Approach for Speed 

Management framework are encouraged to review and identify potential barriers and legal 

constraints to different approaches to determine which of the levers can be used.

Table 6. FDOT Design Manual target speeds and speed management techniques. (continued)
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

State Transportation Policies or Executive Orders

Where permissible, State agencies can adopt design or project prioritization policies that align with 

the Safe System Approach to provide recommendations to other departments of transportation 

(e.g., county DOTs or city DOTs) on how best to improve safety and to provide flexibility for those 

lower-level agencies to deal with specific concerns in their jurisdictions. Two examples of State 

policies that can be used to create a statewide vision of speed management include California’s 

Complete Streets Policy and Washington State’s Injury Minimization and Speed Management Policy.

California’s Complete Streets Policy. Thirty-five States and over 1,500 other jurisdictions in the 

United States have adopted a Complete Streets policy (Smart Growth America 2022). According 

to FHWA’s report to Congress, Moving to a Complete Streets Design Model: A Report to Congress 

on Opportunities and Challenges, a Complete Street is “safe, and feels safe, for everyone using the 

street” (FHWA 2022a). The report notes that Complete Streets embody both the safe roads and safe 

speeds elements of the Safe System Approach, and one of the major areas of emphasis in the report 

is the need to “make Complete Streets FHWA’s default approach for funding and designing nonaccess-controlled roadways” (FHWA 2022a). This emphasis area entails multiple considerations for 

funding and guidance—one of which involves encouraging State DOTs to update design manuals to 

facilitate designing for lower-speed roadways—to help make Complete Streets designs the easiest 

option for stakeholders for all non-access-controlled roadways (FHWA 2022a).

Therefore, the adoption of a Complete Streets policy is a viable mechanism for State DOTs to create 

statewide visions for speed management. One DOT that has embraced this vision is California. In 

2021, Caltrans passed its Complete Streets policy, directing that “in locations with current and/

or future pedestrian, bicycle, or transit needs, all transportation projects funded or overseen by 

Caltrans will provide comfortable, convenient, and connected complete streets facilities for people 

walking, biking, and taking transit or passenger rail unless an exception is document[ed] and 

approved.” (Caltrans 2021). Speed management is an intrinsic component of roadway design that 

meets the needs of all ages and abilities, and the intent of California’s Complete Streets policy is 

to provide design flexibility so that local practitioners can make use of “national and international 

best practices related to traffic calming, speed reduction, universal design, and roadway design to 

increase user safety and comfort.” The policy even notes that flexibility is essential to prioritizing 

safety above other transportation goals (Caltrans 2021), so providing design flexibility through 

a statewide Complete Streets policy is a viable pathway to pursuing a Safe System Approach for 

Speed Management.

Washington State’s Injury Minimization and Speed Management Policy. Although 

Washington State’s working group recommendations for speed management provide many 

applicable suggestions for meeting target speeds, one element that helps create a statewide 

vision is centered on funding structures. In the Injury Minimization and Speed Management 

Policy, the working group recommends the creation of “competitive grant programs... to make 

injury minimization and speed management practices eligible for funding” and to “add injury 

minimization consideration in the selection criteria” (Washington Injury Minimization and Speed 

Management Policy and Guidelines Workgroup 2020).
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

Washington State DOT followed through on this recommendation and modified the prioritization 

practices for the Safe Routes to School program and the Pedestrian and Bicycle program. Relevant 

changes include an emphasis on projects where there are higher operating speeds (greater than 

25 mph) or known speeding problems and on those with quality plans for implementing speed 

management techniques to lower speeds. By changing this prioritization mechanism, the State is 

now more likely to prioritize and fund projects that directly lower speeds and improve safety. These 

changes also make speed management projects more competitive for limited roadway improvement 

funds. By simply changing the application process, Washington State has effectively shifted 

roadway project prioritization toward a Safe System-aligned vision.

 For more information on Washington State’s prioritization program that set a statewide 

vision for safe speeds, see Appendix A.1.

Strategic Plans

States receive Federal funding for the Highway Safety Improvement Program (HSIP), whose 

purpose is to achieve a significant reduction in traffic fatalities and serious injuries on all public 

roads, including non-State-owned public roads and roads on Tribal land (23 U.S.C. 148(b)). To 

obligate HSIP funds, States must develop and update their Strategic Highway Safety Plans (SHSPs) 

(23 U.S.C. 148(c)(1)(a)). States must also set safety performance targets pursuant to 

23 U.S.C. 150(d). These safety performance targets include the following: number of fatalities, 

rate of fatalities, number of serious injuries, rate of serious injuries, and number of non-motorized 

fatalities and non-motorized serious injuries (23 CFR 490.207(a)).

The SHSP is a useful tool for framing State safety concerns, and State DOTs frequently cite 

speeding as an emphasis area within their SHSPs. However, Finkel et al. recommend that, to 

better align SHSPs with the Safe System Approach, State DOTs should refocus the speeding 

emphasis area on speed management rather than relying on education and enforcement only 

(Finkel, McCormick, Mitman, Abel, and Clark 2020). Emphasizing speed management as the key 

to addressing speed problems at the State level may enable State agencies to create a unified vision 

for meeting target speeds while also directing HSIP funds toward addressing the roadway design 

problems that produce unsafe speeds. 

In addition, the Infrastructure Investment and Jobs Act (IIJA) (Pub. L. No. 117-58, also known 

as the “Bipartisan Infrastructure Law” (BIL)) created a new Vulnerable Road User (VRU) Safety 

Special Rule (23 U.S.C. 148(g)(3)) requiring States to dedicate 15 percent or more of HSIP funding 

to safety projects that address VRU safety if total annual VRU fatalities represent 15 percent or 

more of the State’s total annual crash fatalities. VRU projects provide State DOTs an opportunity 

to advance Safe System Approach-oriented countermeasures and speed management techniques by 

addressing limitations in existing right-of-way (FHWA Office of Safety 2022).
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

Roadway Design Manuals

A third mechanism States can use to create a vision for speed management is to set target speed ranges 

for roadway contexts and classifications in their design manuals. Many State DOTs and local agencies 

rely on roadway design manuals for selecting design speeds and geometric design configurations 

for roadways of different functional classifications and contexts. Historically, these design speeds 

have had a flexible relationship to posted speed limits and may facilitate higher operating speeds 

than desired for safety performance (see Section 2.3 for more information). The land use context for 

specific roadways can also change over time. A roadway designed for a specific function and speed 

may no longer match its context after a period of time. An example scenario for this could be a minor 

arterial designed to provide mobility with a design speed equal to 55 mph and a posted speed limit of 

45 mph in a suburban area. If the land adjacent to this roadway gets developed over time to provide 

access to housing and commercial lots, the existing design speed and posted speed limit may no 

longer be consistent with safety performance goals for all modes of travel.

A mismatch between current land use and roadway design can serve as a motivation for setting 

target speeds below the posted speed limit and considering which combinations of traffic calming 

devices or roadway design changes can be reasonably implemented to bring operating speeds closer 

to target speeds based on roadway context. For the previously described example of a roadway 

adjacent to housing, the roadway owner may implement a road diet, repurposing some of the 

right-of-way width to narrow the roadway or to add bicycle lanes and sidewalks.

3.1.4. Establishing a Vision for Speed Management: Mechanisms for Local Agencies

Local agencies like city DOTs and metropolitan planning organizations (MPOs) also have 

pathways for creating visions for speed management. A mechanism by which local agencies 

may establish a vision for speed management is by adopting Vision Zero plans. In fact, most 

early adoptees of Vision Zero in the United States were local agencies trying to deal with local 

roadway problems and to unite stakeholders around a unifying vision of zero traffic deaths and 

serious injuries.

As with State agencies, local agencies can vary significantly in their ability to pursue different speed 

management projects. In some States, cities may own few of the roadways within their jurisdictions, 

and in others, there may be limited capacity for local speed limit setting. Local practitioners 

are encouraged to investigate their legal and policy barriers to determine the extent to which 

programs like Slow Streets (i.e., programs of partially closing streets and installing traffic calming 

devices, often throughout a residential network, to create slow-speed zones) or Vision Zero can be 

implemented (Glandorf 2020).
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

Adopt an Organizing Approach to Planning like Vision Zero

Vision Zero is a strategic goal of preventing all death and serious injury within a jurisdiction. It was 

born out of an ethical concern about traffic deaths in Sweden in 1990s before gaining traction in 

the United States in the mid-2010s (Dumbaugh et al. 2019). The Safe System Approach emerged 

from the principles of Vision Zero first espoused by Tingvall and Haworth (1999) and is often seen 

as the basis or framework for achieving Vision Zero (Johns Hopkins University, ITE, and the FIA 

Foundation 2021). As such, the development of Vision Zero plans has been an effective method 

for local staff to build a coalition around the effort to improve traffic safety and create a vision for 

speed management by emphasizing the effect of speed on fatalities and serious injuries, particularly 

for VRUs. According to the Vision Zero Network, a political commitment to Vision Zero “should 

include passage of a local policy laying out goals, timeline, stakeholders, and a commitment to 

community engagement, transparency, and equitable outcomes” (Vision Zero Network N.D.). This 

commitment can then enable multidisciplinary leadership to develop a Vision Zero plan. According 

to LaJeunesse, Naumann, Sandt, Spade, and Evenson (2020), effective Vision Zero plans typically 

build upon clear safety goals and objectives, identify specific agency actions to meet those goals 

and objectives, specify performance measures for validating the agency actions, and designate lead 

and supporting agencies for accomplishing those actions. A clear Vision Zero plan can unite safety 

stakeholders within a city under a goal of speed management, as shown by the example in Table 7.

 See Appendix A.3. to see how Fremont, CA used Vision Zero to create a unified goal around 

traffic safety that produced a 44 percent decrease in crashes involving speeding.

Additional framing visions for uniting diverse, multidisciplinary stakeholders include Slow 

Streets or Complete Streets programs. See Section 3.1.2 and Section 3.1.3 for more information 

on how Slow Streets and Complete Streets policies and programs can be used to promote speed 

management in your jurisdiction.
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

Table 7. Components of a Vision Zero plan that addresses speed.

Safe Systems Principle: Manage Kinetic Energy Transfer Among Road Users

Goal Traffic speeds in the city are consistent with public health goals.

Objectives By the end of 2022, city staff will have developed street classification 

standards for designing streets with operating speeds of no more than 20 mph 

on local roads, 30 mph on collector roads, 35 mph on arterial roads, and 

45 mph on highways.

By the end of 2026, city staff will have implemented road diets on 50 percent 

of roadways where such treatments are appropriate (e.g., roadway segments 

with more than two vehicle travel lanes and traffic volumes < 20,000 annual 

average daily traffic).

Agency Actions Starting in 2021, city staff will develop a roadway classification scheme designed 

to provide all road users with safe mobility and access to key destinations.

Starting in 2021, city staff will screen the roadway network for locations suitable 

for road dieting.

Performance 

Measures

Online publication of an updated street classification standard indicating design 

speeds by roadway type and a public forum for public input on design speeds.

Percentage of roadways that have undergone road diet lane reconfigurations.

Lead Agency Engineering department.

Supporting 

Agencies and 

Entities

Planning department, public health department, business owners, and local 

stakeholders.

Source: LaJeunesse, S., Naumann, R. B., Sandt, L., Spade, C., and Evenson, K. R. (2020). Guide to Developing a Vision Zero Plan. Chapel 

Hill, NC: Collaborative Sciences Center for Road Safety.

3.1.5. Examples of Establishing a Vision and Building Consensus for Speed 

Management

If an agency seeks to move towards achieving the desired target speeds for minimizing crash 

injuries shown in Table 5, case studies in the Appendix provide information about the activities that 

can be conducted at this stage of the Safe System Approach for Speed Management framework. As 

an example, the City of Portland set a unifying goal with a Vision Zero commitment, determined 

design elements that could be used to achieve target speeds, and used local policy to implement 

those design elements.
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

As discussed in Case Study A.6., the City of Portland, through its Portland Bureau of Transportation 

(PBOT) adopted Vision Zero in 2015 and released an action plan to coordinate traffic safety efforts 

toward Vision Zero in 2016 (PBOT 2016). This action plan presented numerous statistics about 

crashes and injuries in Portland, but it also presented humanizing testimonies about individuals 

killed in the city in motor vehicle crashes, leveraging this emotional appeal alongside a careful 

examination of crash causation to make the case for Vision Zero efforts, especially speed 

management. The action plan discusses the impacts of speed on traffic safety in detail and makes the 

case for injury minimization speeds. The plan also identifies multiple actions, both immediate and 

long term, for addressing speed. Prominently listed are roadway modifications, like narrower lanes, 

on-street parking, street trees, and more. This Vision Zero Action Plan served as the springboard 

for other elements discussed in Case Study A.6 and shows how this vision framing serves as an 

important first stage in the Safe System for Speed Management framework (PBOT 2016).

However, the City of Portland did not merely cast a vision for safe speeds; in the same year the 

city released the Vision Zero Action Plan, it released a memorandum on a proposed speed zone 

methodology. This methodology proposes a simplified speed limit matrix (Figure 13) that identifies 

both ideal speed limits based on traffic composition and traffic calming features needed to achieve 

safe speeds. For example, on roadways where bicycle traffic is desired, if the posted speed limit is 

40 mph, PBOT recommends the use of a permeable barrier to separate bicyclists from potentially 

unsafe vehicle speeds. On streets with speed limits set at 20 mph (the injury minimization 

speed shown for pedestrians in Table 5) or higher, sidewalks and other forms of separation are 

recommended (PBOT 2016). These treatments both separate pedestrians from unsafe speeds and 

may also create visual friction to help slow vehicles down and achieve target speeds equal to 

the posted speed limits. The road reconstruction efforts following these Vision Zero efforts have 

produced numerous speed benefits, including new target speeds on different streets.

An agency seeking to use the Safe System Approach for Speed Management framework does not 

need to follow the exact steps taken by Portland to move from a Vision Zero plan to target speed 

identification, but this framework of building public and official support and then identifying roadway 

designs that leverage that support may be a successful approach. For example, if an agency wants to 

prevent pedestrian fatalities on streets in the urban core, they may do the following:

• Publish relevant communications about the safety of pedestrians in relation to roadway speeds.

• Identify roadways where operating speeds are in excess of target speeds.

• Identify relevant roadway modifications to achieve those target speeds (e.g., bulb-outs or street 

trees in Table 6).

• Change internal policies to make these traffic calming features required parts of new projects.

• Identify roadways to redesign as part of Vision Zero efforts.

 See Appendix A.6. for more information on the City of Portland’s process.
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

3.2. Collecting and Analyzing Speed and Safety Data

3.2.1. Using a Data-Informed Approach

To dispel myths and combat negative perceptions of speed limit reductions, it is crucial to use 

quality data to inform every step of the speed management process. First, information regarding the 

existing network should be gathered and combined to get an assessment of the existing level of safety 

performance on the road network. Data collection provides a secondary benefit, namely earning 

public buy-in to the vision for speed management. Providing information to the public regarding the 

benefits of speed management is important. An open and transparent approach to data collection and 

speed management, especially a public education campaign that informs community members about 

the benefits of target speeds, is beneficial for the success of a program. Key pieces of information that 

can win support for the speed management program include expected reductions in death and serious 

injury crashes and explanations of the decision-making process for determining target speeds. This 

will communicate why a speed management approach was chosen over other safety treatments, such 

as wide-ranging infrastructure improvement projects.

3.2.2. Relevant Data for a Speed Management Program

Agencies routinely collect data relevant to a speed management program when performing 

engineering speed studies (see Section 2.2). All of the speed-related data listed by Forbes, Gardner, 

McGee, and Srinivasan (2012) are relevant, but an expanded list of data types often used to model 

systemic safety include the following (Thomas et al. 2018; Preston et al. 2013; City of Baltimore 

2021; Montgomery County Planning Department 2022):

• Roadway data

◦ Facility type

◦ Number of lanes and lane widths

◦ Shoulder type and shoulder widths

◦ Road edge condition (e.g., presence of side slop or drop off)

◦ Access point density

◦ Superelevation (a measure of the tilt or bank or a road’s profile)

◦ Curvature (horizontal and vertical)

◦ Number of legs (for intersections)

◦ Skew angle (at intersections)

◦ Pedestrian, bicyclist, and rail crossings (number and type)

◦ On-street parking

◦ Sidewalks and bicycle facilities

◦ Accessible ramps and other ADA-facilities

◦ Transit facilities
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

• Traffic volumes

◦ Vehicular annual average daily traffic (AADT)

◦ Turning movements

◦ Vehicle composition (especially types of heavy vehicles)

◦ Number of pedestrians

◦ Number of bicyclists

◦ Number of micromobility users

• Speed data

◦ Posted speed limits

◦ Operating speeds

• Traffic control type and location

◦ Additional pedestrian or bicycle intervals

◦ Turning phases

• Lighting facilities and location

• Crash history

◦ Fatal and injury crashes

◦ Speeding-related crashes

• Other contextual data

◦ Transit stops

◦ Adjacent development types

◦ Points of interest (e.g., schools)

• Equity emphasis area indicators and metrics

Although collecting these data for an entire network may be time and resource intensive, doing so 

will enable analysts to thoroughly identify at-risk sites in need of treatment. Agencies often use 

these data on a network basis to build safety performance functions and other crash models that can 

be used to calculate predicted and expected crashes based on road use context and traffic volumes in 

accordance with the HSM (AASHTO, 2010).

Because the intent of a Safe System Approach for Speed Management framework is to prevent 

fatal and serious injury crashes, these crash types may be considered the focus crashes for modeling 

efforts. Agencies may examine crash histories and crash prediction models to determine locations 

where fatal and injury crashes are overrepresented compared to expected values. These locations 

can then be cross referenced to locations where speed limits or operating speeds are more than 

the desired target speeds. This comparison will then inform the process of project prioritization. 

Although speeding is not the key focus of this framework, speeding-related crashes may provide 

additional context to identify locations with speed-related safety problems.
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

 See Appendix A.7 to learn how Seattle DOT examined speed limit and traffic-volume data to 

identify locations for treatment as part of its speed management program.

Another key factor is traffic composition. Section 2.4 addressed the relationship between vehicle 

mass, kinetic energy, and crash severity. One consideration for agencies implementing a Safe 

System Approach for Speed Management framework is to examine traffic composition and to 

identify routes where heavy vehicles are common; even if operating speeds at these locations match 

target speeds, heavy vehicles may increase the net kinetic energy of a crash and create additional 

risk of death or serious injury. Heavy vehicle routes may also be considered during project 

prioritization.

3.2.3. Quality Data Are Key

Speed has been cited by researchers as one of the most desired and needed data types for safety 

analyses, but researchers often rely on surrogate data, such as speed limit data, to estimate the 

operating speeds or impact speeds of vehicles involved in crashes (Nordback et al. 2019).

Even existing Safe System Approach methods, like the FHWA Safe System-Based Framework and 

Analytical Methodology for Assessing Intersections (SSI) typically rely on assumptions of operating 

speed to predict crash severity (Porter et al. 2021).

While newer methods of collecting speed data—such as from probe vehicles and connected 

vehicles—are available, these data sources are not without their own limitations. These data sets 

are collected by private corporations and are available to agencies at some cost to be linked to 

roadway data by traffic message channels. Regardless of the method of collection, agencies should 

consider implementing network wide speed data collection efforts to provide accurate data for speed 

management programs.

 Appendix A.2 details how Bellevue, WA, used video cameras to analyze speeds across the 

transportation network.

Limitations of Speed Information from Crash Data

The main safety data collected by agencies are police reported crash data. However, crash data also 

have their own limitations for application within a Safe System Approach for Speed Management 

framework. First is the problem of potential inaccuracy in the reporting methods. While crash 

data do indicate whether a driver was speeding, this variable may not be objective and may not 

accurately capture pre-crash driver behavior (Khattak, Ahmad, Wali, and Dumbaugh 2019). As 

mentioned, measures of impact speed in crash data are likely only estimates (Harmon, Hancock, 

Rodgman, Sandt, and Thomas, 2021). Secondly, completed crash reports frequently under report 

or miss collisions involving pedestrians, and the severity of pedestrian injuries are often inaccurate 

(Harmon, Hancock, Rodgman, Sandt, and Thomas 2021).
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

Agencies can use various statistical and data science methods to overcome these limitations, but not 

every agency will have the personnel capacity or technical knowledge to apply these corrections. 

One problem with assessing the utility of different speed management countermeasures is that 

transportation agencies do not always collect accurate project installation and completion data 

(Nordback et al. 2019). Accurate project data can allow practitioners to perform comparative 

before-after studies to get a better sense of the true capacity for a treatment to reduce speed-related 

crashes, but this methodology requires both a sufficient number of years of data before and after 

treatment installation and a statistical methodology (such as the Empirical Bayes approach) to 

account for potential biases in crash and traffic volume trends. Please see Carter et al. (2012) for 

more information on conducting accurate before-after studies.

Given these various limitations in available data, agencies seeking to supplement traditional 

systemic safety data may consider the following:

1. Collect network-wide operating speed data.

2. Maintain accurate records of project installation and completion.

3. Adopt Safe System Approach-based risk measures (e.g., FHWA’s SSI method (Porter et al. 

2021)) to identify risks proactively.

See the FHWA report Safe System Approach in the Urban Core for a case study on how to use the 

SSI methodology to identify risks at intersections (FHWA 2023).

3.2.4. Examples of Collecting and Analyzing Speed and Safety Data

In Section 3.1.5., the City of Portland case study was discussed to present an example of how an agency 

might work through the first stage of the Safe System Approach for Speed Management framework. 

The second stage, Collecting and Analyzing Speed and Safety Data, is crucial for the process outlined 

in that section. For agencies to determine roadways to identify as part of Vision Zero efforts, speed and 

safety data are critical. At a minimum, agencies may consider examining a network wide database of 

speed limit and crash data. Operating speed data should also be appended to the network dataset to the 

extent possible.

The Montgomery County, Maryland, speed program, discussed in Case Study A.4., began with a 

careful analysis of a variety of data types—resident complaints, crash data, active traveler volumes, 

and environmental data, among others—paired with operating speed data to identify locations where 

operating speeds exceeded posted speed limits. However, the County’s analysis did not end at an 

examination of operating speeds; county personnel routinely visit sites with reported speed problems 

to inspect the locations and determine the feasibility of using enforcement cameras as well as their 

potential impacts on people walking nearby. These field visits can help determine the viability of 

enforcement efforts, but they may also indicate other countermeasures that may be more effective.
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

Agencies collecting speed and safety data as part of a Safe System Approach for Speed Management 

framework may consider the many types of data beyond simple crash counts and speed limits that 

can help them identify specific locations with speed problems, but also network wide risks related 

to speed. For example, under its Vision Zero program, Montgomery County’s Planning Department 

combined a wide variety of data—including road user volumes, land use measures, equity indicators, 

roadway features, speed limits, transit locations, and more—to use in crash prediction models to 

identify locations of risk on segments and at intersections across its entire network ( Montgomery 

County’s Planning Department 2022).

Agencies with access to a wide variety of data may also develop systemic crash prediction models 

to locate network wide risks where speed may be a factor in crashes, but agencies may also simply 

consider the locations where operating speeds and speed limits differ from target speeds for the 

intended purpose of the roadway. To continue the example from Section 3.1.5, agencies seeking 

to improve pedestrian safety in the urban core may consider all locations where operating speeds, 

collected by law enforcement or as part of engineering speed studies exceed target speeds (i.e., 

25 mph), and then combine these two data points to determine potential treatment locations. Crash 

data or hospitalization data (Harmon et al. 2021) may inform this location prioritization as well. At 

a minimum, agencies should consider collecting speed data on all roadways within a jurisdiction in 

order to make informed decisions aligned with the Safe System Approach.

3.3. Prioritizing Locations for Speed Management Proactively

A core principle of the Safe System Approach is that “safety is proactive. Proactive tools should be 

used to identify and mitigate latent risks in the transportation system, rather than waiting for crashes 

to occur and reacting afterwards (Doctor, Ngo, Ocel, Scurry, and Shaw 2020). Transportation agencies 

can use the Safe System Approach for Speed Management framework to proactively identify those 

locations where operating speeds exceed target speeds, which may increase the risk of death or 

serious injury to road users; take an area-based approach; and design roadways proactively to meet 

target speeds and prevent speed-related safety problems.

3.3.1. Prioritizing Locations for Systemic Countermeasure Implementation

Traditional safety analysis based on crash reports treats the problem after crashes have occurred. 

Further, the categories typically used to describe speeding-related crashes include “exceeded 

speed limit”, “driving too fast for conditions”, “following too closely”, and “driving aggressively”, 

which focus on human error as the crash contributing factor rather than fully describing the 

circumstances surrounding the crash. Practitioners can apply the Safe System Approach for 

Speed Management framework by adopting a systemic, proactive network screening and 

diagnosis of speeding-related crashes.
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

Systemic safety initiatives can use information from well documented serious crashes (fatal and 

serious injury crashes) to identify the most prevalent crash types, facility types, and risk factors 

(Preston, Storm, Bennett, and Wemple 2013; Thomas et al. 2018). This information enables an 

agency to identify locations with roadway characteristics similar to those of known fatal and 

serious crash locations and preemptively prevent crashes from occurring at those sites (FHWA 

2019). Depending on the type of countermeasure used, it may be more effective and proactive to 

implement several low cost projects that address risk across the entire roadway network rather than 

selecting expensive countermeasures that only address speed-related safety problems at a small 

number of hot spots. See Gross, Harmon, Bahar, and Peach (2016) for more information on the 

balance of countermeasure cost and crashes prevented.

 Appendix A.9 contains an interesting case study on a network-wide speed management 

program in Australia.

The Safe System Approach for Speed Management framework, with its emphasis on injury 

minimization, fits into the first four components of a systemic safety project selection procedure. 

For example, an agency might do the following:

1. Select high speed angle crashes (likely to result in fatalities) as the focus crash type.

2. Use crash data to identify intersections where a combination of posted speed limits and 

signal timing plans correspond to the potential for high speed angle crashes with increased 

risk of severity. The use of crash data in this approach is proactive and intended to be used in 

predictive modeling to identify locations of risk rather than to treat hot spots.

3. Select speed management treatments (e.g., conversion to roundabout) that will reduce the 

potential for high-speed angle crashes to occur.

4. Prioritize treatment intersections based on the greatest potential for fatalities to occur.

The final two steps of the systemic safety process are also relevant but relate less to the Safe System 

Approach. Agencies should regularly collect data and monitor safety so that speed management 

programs can be fine-tuned; these data will also enable agencies to communicate the benefits 

of speed management to the public to aid in building compliance with network-wide speed 

management applications.

Prioritization may vary depending on the type of jurisdiction responsible for project delivery. State 

agencies implementing speed management treatments along State-owned roads may consider using 

a speed management emphasis area, as identified in a SHSP, to prioritize State highway safety 

improvement projects and ensure that the riskiest sites are prioritized.

Oregon DOT (ODOT) has implemented this type of risk-based application of (primarily) HSIP 

funds through its All Roads Transportation Safety (ARTS) program. As part of this program, ODOT 

splits roadway safety funds evenly between hot spot treatments and systemic treatments and then 

prioritizes active prevention through systemic projects. Researchers collaborating with ODOT to 

implement a systemic approach to pedestrian and bicycle crash prevention collected various data 

sets and then worked with ODOT to assign weights to risk factors identified in these datasets. One 

of the most important risk factors identified was whether the posted speed limit exceeds 35 mph. 
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After weights were assigned, ODOT then used these weights to score State roadways for treatment 

(Foster et al. 2020). Practitioners are encouraged to review Foster et al. (2020) to see how ODOT 

implemented a systemic approach using speed limit data to identify locations for treatment using 

HSIP funds allocated through its ARTS program.

3.3.2. Schemes for Prioritization

There are a variety of data sources or metrics that could be used to prioritize treating locations in 

addition to the data discussed in Section 3.2.2. These considerations include equity and desired 

activity. These prioritization schemes can be used in conjunction with the systemic approach 

discussed in Section 3.3.1. For example, agencies may find success in implementing speed 

management countermeasures by systemically identifying locations that pose risks to specific 

types of road users (e.g., VRUs) and then may rank those treatment locations by considering equity 

implications or desired activity levels. This approach could lead an agency to prioritize the top ten 

sites where the speed limits are highest and where pedestrians should be the most highly prioritized 

type of road user.

Regardless of the method used for project prioritization, agencies may involve relevant 

stakeholders, particularly from locations where projects will be implemented, to ensure that speed 

management activities are beneficial to those most affected and to continue to build a shared vision 

for speed management.

Equity

Historically, inequitable transportation planning and development patterns have led to the social 

cost of traffic crashes being born unequally by Black and Indigenous road users or populations in 

marginalized communities (Johns Hopkins University, ITE, and the FIA Foundation 2021; USDOT 

2022a). Throughout the United States, roadways have been designed and built to provide high 

speeds through some communities at the expense of the people living in those communities. In the 

Portland, Oregon, metropolitan area, 67 percent of pedestrian fatalities and 72 percent of serious 

injury pedestrian crashes occur in equity focus areas where people of color (especially Black and 

Indigenous peoples), people with lower income, and people with limited English proficiency are 

disproportionately affected by crashes. Additionally, 50 percent of high-injury corridors (250 miles) 

in the Portland metro area are in areas with above average densities of people of color, while only 

41 percent of the population lives in these areas (FHWA 2020c).

Other research efforts report similar inequitable safety outcomes around the country, confirming 

that pedestrian fatalities tend to be concentrated in low-income communities and communities of 

color, while Native American communities especially are disproportionately at risk of all total traffic 

fatalities (Grant and Bowen 2020). These locations may provide significant net benefits to traffic 

safety if speed-related problems can be addressed.
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

Desired Activity

Placemaking may be a useful concept for framing local transportation and planning design decisions 

with an emphasis on speed management. Placemaking is an approach to planning public spaces—

especially transportation facilities—wherein the physical and social qualities of a public space are 

balanced to promote health and well-being (Flynn and Yassin 2012). In the context of transportation, 

the placemaking approach entails carefully considering who can (or should) use a roadway to reach 

a destination. Agencies can integrate placemaking concepts with speed management by considering 

the land use context of a location in terms of movement and place.

A practical application of using placemaking concepts to prioritize locations for speed management 

projects in the United States is a city identifying locations intended to serve as places that currently 

have a significant number of deaths or serious injuries. At these locations, it may be beneficial 

to both lower speed limits and implement traffic calming measures, or to provide separation for 

pedestrians and bicyclists if vehicular movement is still necessary near the place. The PBOT, as 

part of its Vision Zero initiative, created a Simplified Decision Matrix (Figure 13 in the Appendix) 

to assist staff in creating low speed environments wherever pedestrians and bicyclists will use 

the roadway (Vision Zero Network n.d.). These provisions include low speed limits, dedicated 

sidewalks, bike lanes (even with low speed limits), and minimum lane widths when pedestrians 

and bicyclists may be present. The combined effect is to provide visual friction on roadways where 

pedestrian and bicyclist activity is expected and to provide separation to pedestrians and bicyclists 

when higher mobility is desired.

 For more information on speed management activities and PBOT’s vision of the Safe System 

Approach, see Appendix A.6.

Other jurisdictions in the United States have developed similar modal hierarchies for roadway 

projects and prioritized funding to improve the safety of road users based on desired activity. For 

example, in its Complete Streets Policy, the City of Baltimore developed the modal hierarchy that 

prioritizes, in the following order (City of Baltimore 2021):

1. Walking

2. Cycling, public transit, and micromobility

3. Taxis, commercial transit, and shared vehicles

4. Single occupant motor vehicles

Given the biomechanical vulnerability of pedestrians and bicyclists discussed previously, 

proactively prioritizing streets that improve safety for these modes rather than addressing where 

crashes occur is an effective method to address safety issues and apply Safe System principles.

Agencies seeking to incorporate movement and place metrics into a prioritization framework may also 

consider multimodal indicators of road use comfort, also known as “walkability” and “bikeability.” 

The walkable or bikeable nature of a roadway is often measured in terms of the level of service or the 

amount of traffic stress non-motorized road users feel on roadway. The walkability and bikeability of a 

roadway are directly related to the design of the roadway environment, so while they may not be direct 

measures of safety, they can act as surrogate indicators of risk (Caviedes and Figlioizzi 2018).
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Researchers have integrated the concept of place into crash prediction models and found that spatial 

indicators of pedestrian and bicyclist activity are important for determining where crashes might 

occur (Wang, Huang, and Zeng 2017). If agencies have access to spatial correlates of activity, 

like pedestrian level of service, these data may help agencies identify locations where operating 

speeds cause stress to nonmotorized road users. This information can then be used to manage 

speeds proactively at these locations before crashes occur. A recent National Cooperative Highway 

Research Program (NCHRP) publication provides information to practitioners seeking to measure 

pedestrian level of service for consideration using Highway Capacity Manual methodologies 

(Ryus et al. 2022).

3.3.3. Examples of Proactively Prioritizing Locations for Speed Management

The third stage of the Safe System Approach for Speed Management framework directly builds 

upon the data collection activities described in Section 3.2.4. The City of Fremont’s speed 

management activities, discussed in Case Study A.3., illustrate one example of an agency extending 

its Vision Zero activities from vision framing to data collection to project prioritization.

As discussed in Section 3.2.4., a variety of different data types can reveal locations along a roadway 

network that may have speed problems. As part of its traffic safety management program, the City 

of Fremont used multiple methods of project prioritization, including the following:

• Hot spot identification of locations with clear safety problems

• Systemic identifications of locations that can be proactively treated with systemic 

countermeasures

• Safe neighborhoods program to reduce speeds in residential areas

These various prioritization schemes can leverage different data to give agencies a list of 

potential locations for treatment. Hot spot identification may rely on crash data, but systemic 

and neighborhood approaches may simply rely on datasets of operating speeds and speed limits. 

The City of Fremont reports that its approach to speed management and project selection has 

demonstrated both a 45 percent decrease in fatal and serious injury crashes and a 44 percent 

decrease in crashes involving speeding.

To continue the example from Section 3.2.4., an agency that has collected data on roadways in 

the urban core where the target speed is 25 mph to facilitate pedestrian travel may examine all 

roadways of that type in the entire urban core network and then prioritize locations for treatment 

based on the following factors:

1. Where operating speeds and speed limits are in excess of target speeds (and by how much)

2. Where systemic, low-cost countermeasures can be installed quickly

This approach to prioritization may not even require the use of crash data for agencies to quickly 

make countermeasure selection decisions, enabling agencies to respond to speed problems 

proactively rather than reactively.
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3.4. Selecting Speed Management Strategies

Transportation practitioners can implement several strategies to manage speeds on roadways. The 

initial consideration in speed management should be setting speed limits that are both consistent 

with the roadway context and safe for all road users (FHWA 2017c). Higher speed limits are linked 

to higher crash severity (Doecke, Kloeden, Dutschke, and Baldock 2018), and studies show that 

lowering speed limits can lower vehicle speeds (Hu and Cicchino 2020). A few strategies for an 

effective speed management program are described in this section.

3.4.1. Determine Appropriate Speed Limits to Match Target Speeds

The Safe System Approach can be applied to speed limit setting by incorporating the needs of all 

road users rather than focusing on vehicle operational speeds. Setting appropriate speed limits to 

reduce the risk drivers impose on others, especially VRUs, and on themselves is an FHWA Proven 

Safety Countermeasure (FHWA 2021). Target speeds should be consistent with a specific context 

to provide both mobility for motor vehicles and a safe environment for pedestrians, bicyclists, 

and public transit users. Setting appropriate speed limits can reduce fatalities and serious injuries 

(Doecke, Kloeden, Dutschke, and Baldock 2018; FDOT 2016).

Where statutory speed limits do not fit a specific road, traffic context, or land use, speed zones may 

be established, and speed limits may be set by an engineering study, taking into account the context 

of the location. As an example, FDOT reduced the speed limit on the Busch Boulevard corridor 

from 45 mph to 35 mph (FDOT 2018). Further, jurisdictions can develop their own methodology to 

set speed limits based on target speeds. The PBOT developed a decision matrix for speed zones on 

non-arterial roads with posted speed limits greater than 25 mph, with focus on the safety of VRUs 

(PBOT 2016).

Although matching operating speeds with target speeds is the end goal, intermediate target speeds 

may be necessary to achieve public buy-in. The Washington State Department of Transportation 

(WSDOT) establishes target speeds and considers a phased approach where the operating 

speed exceeds the target speed by 5 mph or more (Washington Injury Minimization and Speed 

Management Policy and Guidelines Workgroup 2020). WSDOT uses an engineering study to 

determine iterative speed limits and implements speed management techniques. Incremental 

adjustments of 5 mph or more are made until the target speed is achieved.

3.4.2. Inform the Public about Speed Management Benefits to Build Support

Lower speeds in urban environments promote physical activities such as walking and cycling. 

Lower speed limits also improve accessibility and equity of access to the transportation system. 

Creating environments where all people feel safe further helps to make a public network accessible 

to all members of the public.
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Lower speeds also reduce vehicle emissions, and even minor decreases in operating speed result 

in substantial reductions in carbon emitted from vehicles. These reductions decrease the impact of 

emissions on climate change and improve air quality, especially for road users not inside vehicles 

(Gonzalez and Lungu 2021). Improved air quality resulting from lower speeds can result in fewer 

negative health impacts due to air pollution. Again, this is more important for the vulnerable 

members of society who have existing health conditions.

3.4.3. Identify and Implement Roadway Redesign or Behavioral Treatments to 

Support Speed Limit Changes

Engineering and enforcement measures can be implemented to support lower speed limits. In 

addition to lowering the default arterial and non-arterial speed limits to 25 mph and 20 mph (from 

30 mph and 25 mph), the City of Seattle used road diets, signal timing modifications, and increased 

speed limit sign density to reduce vehicular speeds (City of Seattle, 2015). Similarly, New York City 

created a speeding solutions toolkit that incorporated school zone automated enforcement, police 

enforcement, speed humps, speed cushions, and street redesign projects to support the reduced 

citywide default speed limit of 25 mph (City of New York 2020).

 See how New York City took a comprehensive approach to speed management using the 

Speeding Solutions Toolkit, as discussed in Appendix A.5.

In summary, examples of countermeasures that practitioners should consider using to support 

context-sensitive speed limits include the following:

Roadway Treatments

Roadway treatments include vertical deflections (e.g., speed humps, speed tables, raised 

intersections), horizontal shifts (e.g., chicanes), roadway narrowing (e.g., road diet, lane-width 

reduction), intersection treatments (e.g., closures, raised intersections, protected intersections, 

intersection turn calming), and signal timing modifications. Typically, residential streets or streets 

where the primary function is to provide access to abutting residential property are appropriate for 

vertical deflections. Consideration should be given to minimizing conflicts with emergency vehicles 

and transit services (FHWA and ITE 2017). Further, vertical deflections must be properly designed 

to avoid adverse impacts on individuals with disabilities. Speed humps, which include a raised 

area in the roadway pavement surface extending across the travel way with significant length, are 

recommended to promote vehicular speed reduction without compromising comfort for all other 

road users (ITE 2022).

Table 8 lists complementary infrastructure treatments that were identified as being effective in 

reducing speeds and crashes (Hillier, Makwasha, and Turner 2016). These vary between roadway 

treatments and behavioral treatments and may have different uses in different contexts. Please 

refer to Hillier, Makwasha, and Turner (2016) for more information.
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

Table 8. Complementary speed management infrastructure treatments: 

speed and crash reductions.

Treatment Speed Reduction Crash Reduction

Vehicle Activated Signs 

(e.g., Changeable Message 

Signs)

3 mph reduction in 85th percentile speed 70% reduction in 

crashes

Roundabouts 6 mph reduction in 85th percentile speed 75% reduction in 

crashes

Raised Intersections 

(intersections with vertical 

deflection)

5 mph reduction in 85th percentile speed Not 

common in U.S.

40% reduction in 

casualty crashes

Horizontal Deflection 

(e.g., curb extensions)

Up to 3 mph reduction in speed 30% reduction in 

pedestrian crashes

Perceptual Countermeasures 

(e.g., painted speed bars that 

make drivers feel they need 

to slow down)

8 mph reduction in 85th percentile speed from 

perceptual narrowing 7 mph reduction in 85th 

percentile speed from lane narrowing through 

buildings, parked cars, etc.

Up to 5 mph reduction in 85th percentile speed 

from markings that give the appearance of 

travelling faster on the approach to an intersection

-

Transverse Rumble Strips Up to 3 mph reduction in speed 30% reduction in 

fatal and serious 

injury crashes

Reduce Excessive Sight 

Distance at Roundabouts

Up to 12 mph reduction in 85th percentile speed at 

roundabouts

Up to 40% (CMF 

0.60) for reductions 

in excess sight 

distances at 

roundabouts

Lower speed limits 4 mph reduction in 85th percentile speed. 

Note: In other literature, this varies greatly 

depending on the speed environment. For 

example, assuming a 4 mph speed reduction in an 

urban environment with high vulnerable road user 

demand would be unreasonable.

25% reduction in 

casualty crashes

Variable Speed Limits 

(VSL)

Evidence of overall reductions in speed 8% reduction in 

casualty crashes

Changeable Message Signs 1 mph reduction in mean speed 10% reduction in 

injury crashes

- No data. 

Source: Hillier, P., Makwasha, T., and Turner, B. (2016). Achieving Safe System Speeds on Urban Arterial Roads: Compendium of Good 

Practice. Sydney: Austroads.
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 Refer to Appendix A.10 to see how speed limit changes fit into a broader speed management 

program in South Korea.

Behavioral Treatments

Behavioral treatments include increased speed limit sign density, speed feedback signs, 

traditional enforcement, and automated enforcement. Speed safety cameras are included in 

FHWA’s Proven Safety Countermeasures (FHWA Office of Safety 2021). It is important to note 

that a few of these countermeasures may not be useful in certain temporal distributions. For 

example, police enforcement may not always be available due to other occupational demands, 

and existing design issues that can lead to higher speeds (i.e., capacity) may not be addressed by 

these behavioral countermeasures.

3.4.4. Countermeasures for Improving Speed Limit Compliance

A posted speed limit is sometimes the same as the statutory speed set by the State legislature, 

or it is established by a city, county, or State transportation agency (FHWA 2017a). Modifying 

speed limits based on a specific context may not always be possible. In certain cases, the existing 

posted speed limit is appropriate based on the context but concerns with speed limit compliance 

exist. Practitioners can still implement supporting treatments for reducing vehicular travel speeds 

without changing the speed limits, such as through public outreach, behavioral treatments, and 

roadway treatments.

Inform the Public and Get Buy-In

In Montgomery County, Maryland, more than 60 percent of residents supported their automated 

enforcement program after it started following extensive community outreach. After final approval 

for a camera location, the site must be advertised in a newspaper of general circulation prior to 

conducting enforcement (Montgomery County Department of Police 2022).

Identify and Implement Behavioral Treatments To Support Speed Limits

Behavioral treatments such as increased speed limit sign density, speed feedback signs, traditional 

enforcement, and automated speed safety camera enforcement can support speed limit compliance.

Identify and Implement Roadway Design Changes To Achieve Speed Limits

In addition to driver behavior, the Safe System Approach addresses human vulnerability to crash impact 

forces, and the roadway infrastructure can be designed to reduce crash severity. Vertical deflections 

(e.g., speed humps, speed tables, or raised crosswalks), horizontal shifts (e.g., chicanes), roadway 

narrowing (e.g., road diet, lane width reduction), roadway closures ( e.g., median barriers, hardened 

centerlines), intersection treatments (e.g., raised intersections, protected intersections, intersection turn 

calming), and signal timing modifications are effective measures to reduce travel speeds.
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3.4.5. Speed Management Resources

As discussed, speed management includes setting the appropriate speed limit, when possible, and 

supporting lower travel speeds with behavioral and roadway design countermeasures.

There are several speed management resources available for practitioners that may help readers 

select appropriate countermeasures from Table 8, as well as other interventions that may not be 

referenced there. Each tool has specific context, advantages, and disadvantages, as discussed below. 

It is important to note that these resources can be used as part of an engineering study for nonstatutory speed limits; however, they do not replace any required engineering study.

Speed Limit Resources

USLIMITS2 (FHWA 2020b): USLIMITS2 is a web-based tool that helps practitioners set 

reasonable, safe, and consistent speed limits for specific segments of roads. The tool is applicable 

to all types of roads except for school zones or construction zones. The tool considers the following 

major factors: operating speed (50th and 85th percentile), annual average daily traffic, roadway 

characteristics and geometric conditions, level of development in the area around the road, crash 

and injury rates, presence of on-street parking, extent of pedestrian and bicyclist activity, as well 

as several other factors depending on the road type. USLIMITS2 is an expert systems tool and 

has increased safety considerations compared to previous versions. For example, USLIMITS2 

recommends speed limits close to the 50th percentile speed instead of the 85th percentile speed for 

roadway segments that experience high pedestrian and bicyclist activities. USLIMITS2 is currently 

being updated under project NCHRP 03-139 “Next Generation of the USLIMITS2 Speed Limit 

Setting Expert System.”

NACTO City Limits (NACTO 2020): This tool provides cities with technical and policy guidance 

on setting safe speed limits on urban streets, which pose the most complex and challenging 

scenarios for determining speed limits where there is considerable pedestrian and bicyclist presence. 

NACTO City Limits is a context-sensitive method that includes three primary tools for setting 

speed limits in urban areas: setting default speed limits on many streets at once, designating slowspeed zones in sensitive areas, and setting corridor speed limits on high-priority major streets. This 

tool focuses on a defined safety target to set speed limits rather than percentile-based systems that 

focus on operating speeds, allowing cities to holistically evaluate who is using streets and how those 

individuals are using them.

NCHRP Report 966 (Fitzpatrick, Das, Pratt, Dixon, and Gates 2021): This manual provides a 

procedure for setting speed limits, a practitioner user manual explaining the speed limit setting 

procedure, and a speed limit setting tool. The tool considers factors beyond the 85th percentile 

speed, including both driver speed choice and safety associated with the roadway. NCHRP Report 

966 includes the following variables for speed limit setting: roadway context, roadway type, speed 

data (50th percentile speed, 85th percentile speed, and maximum speed limit), site characteristics 

(segment length, traffic volumes, number of lanes, pedestrian and bicyclist activity level, pedestrian 

facilities, and other attributes describing the segment’s design and traffic control characteristics), 

and crash data (crash frequency, years of crash data, crash severity, exposure, and others). This tool 

can be used on all road types (interstates, principal arterials, minor arterials, collectors, locals) and 

across all contexts (rural, rural town, suburban, urban, urban core).
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

Infrastructure/Speed Limit Relationship in Relation to Road Safety Outcomes (Jurewicz and 

Turner 2010): This report was published by Austroads and focuses on the Safe System Approach. 

It provides advice to jurisdictions on appropriate speed limit setting policy in light of injury 

minimization. This advice was based on the improved understanding of the relationships between 

infrastructure, speed limits, driver selection of speeds, and crash outcomes.

Infrastructure Resources

FHWA Road Diet Guide (Knapp et al. 2014): This tool guides practitioners through the decisionmaking process to determine if road diets are a good fit for a certain corridor. It also provides design 

assistance and encourages post-implementation evaluation. The road diet feasibility determination in 

this guide includes safety factors (crash patterns); context-sensitive solutions and Complete Streets 

qualities; operational factors (speed, traffic volumes, level of service, quality of service, and so 

on); bicycle, pedestrian, and freight considerations; right-of-way availability and cost; parking; the 

presence of railroad crossings; public outreach; public relations; and political considerations.

FHWA Self-Enforcing Roadways Guidance Report (Donnell, Kersavage, and Fontana Tierney 

2018): This tool guides users to identify methods that may produce self-enforcing, or selfexplaining, roadways during the geometric design process. The FHWA Self-Enforcing Roadways 

Guidance Report describes six methods for self-enforcing roads: speed feedback loop, inferred 

design speed approach, design consistency methods, application of existing geometric design 

criteria, combination of signs and pavement markings, and setting rational speed limits. This tool 

focuses on methods to mitigate speeding-related crashes on planned and existing two-lane rural 

highways with posted speed limits of 35 mph or greater.

Behavioral Resources

FHWA Speed Safety Cameras (FHWA Office of Safety, 2021): Speed safety cameras are an 

FHWA proven safety countermeasure. Agencies can use speed safety cameras as an effective and 

reliable technology to supplement more traditional methods of enforcement, engineering measures, 

and education to alter the social norms of speeding. Speed safety cameras use speed measurement 

devices that detect speeding and capture photographic or video evidence of vehicles that are 

violating a set speed threshold.

Speed feedback signs: Although there is no specific tool for practitioners to follow regarding 

the use of speed feedback signs, research can guide practitioners on how this countermeasure is 

effective in reducing speeds. An example includes use of dynamic speed feedback signs in small 

rural communities in Iowa (Hallmark, Hawkins, and Knickerbocker 2015).

Federal Funding Resources

Highway Safety Improvement Program: Where consistent with HSIP requirements, Federal 

funding can be used through the HSIP to implement speed management countermeasures specified 

in State SHSPs. The role of the HSIP and SHSP in a Safe System Approach for speed management 

are discussed in greater depth in Section 3.1.3. 
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Safe Streets and Roads for All (SS4A): The Bipartisan Infrastructure Law (Pub. L. No. 117-58) 

establishes a new SS4A competitive grant program, which sets aside $5 billion over 5 years. Under 

this grant, eligible jurisdictions can apply to receive funds to implement speed management efforts, 

among other safety-oriented projects and activities. In addition, MPOs, political subdivisions 

of a State, federally recognized Tribal governments, and multijurisdictional groups of these 

entities are all eligible to apply for these grants to develop Comprehensive Safety Action Plans; 

conduct planning, design, and development activities for projects and strategies identified 

in a Comprehensive Safety Action Plan; and carry out projects and strategies identified in a 

Comprehensive Safety Action Plan (USDOT 2022b).

3.4.6. Examples of Selecting Speed Management Countermeasures

Section 3.3.3. discussed prioritization methods for proactively using data to identify locations 

suitable for speed management countermeasures. Two case studies in the Appendix provide 

examples of how agencies have moved from prioritization to implementation, with a different 

emphasis in each case.

The City of Bellevue—as discussed in Case Study A.2.—conducted a comprehensive speed data 

collection process and determined its own Neighborhood Slow Zone program was a viable method 

for prioritizing countermeasures that could be installed quickly. The city began systemically 

installing speed feedback signs across this network of neighborhood slow zones to reduce vehicle 

speeds. Fisher et al. (2021) reports that the general research consensus is that dynamic speed 

feedback signs are effective across a comprehensive range of location types at reducing operating 

speeds, with many studies showing reductions in mean speeds, 85th percentile speeds, and 

speeding behaviors.

Conversely, the example of the City of Seattle—discussed in Case Study A.7.—demonstrates that 

simply lowering speed limits systemically as part of a proactive speed management program can 

produce significant benefits to safety. The city’s efforts, which included lower speed limits and 

increased speed limit sign density, produced the following benefits:

• A 22 percent reduction in all crashes and 18 percent reduction in injury crashes

• A 10 percent reduction in 50th percentile speeds and 7 percent reduction in 

85th percentile speeds

• A 54 percent reduction in the number of vehicles traveling at or faster than 40 mph 

Critically, the city did more than just lower speed limits at locations where the roadway design 

may not be self-explanatory to cue motorists to drive at the target speeds. For example, in addition 

to lowering the speed limit on Rainier Avenue South, the city also implemented a road diet and 

converted the road from four lanes to three lanes. Speed limit reductions alone may not always be 

sufficient to change operating speeds, so agencies may also consider geometric design changes that 

will increase visual friction to slow drivers down.
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To continue the example from Section 3.3.3., after an agency has identified urban core roadways 

where speed limits and operating speeds exceed the intended target speed of 25 mph, they may then 

identify locations where systemic, low-cost treatments (e.g., speed feedback signs or speed tables) 

can slow traffic to 25 mph. They may also identify locations where the number of lanes or building 

setbacks along corridors induce speeds above 25 mph and then select those sites for more extensive 

reconstruction projects. Agencies may consider scanning the list of different countermeasures 

discussed in Section 3.3.3 and then diagnose the roadway environments along the prioritized list of 

networks to determine which countermeasures will work best to slow driver speeds.

3.5. Ongoing Monitoring, Evaluation, and Adjustment

Agencies implementing a Safe System Approach for Speed Management framework are 

encouraged to think of the framework not as a linear process but as a cycle moving the agency 

towards prevention of death and serious injury on their roadways. After agencies have identified 

locations for treatment, prioritized projects based on equity and alignment with a speed management 

vision, and implemented countermeasures to produce target speeds at those locations, agencies are 

still encouraged to collect speed and risk data and to monitor the outcomes of their projects.

Safety performance can change over time, and speeding behavior can migrate across a network, so 

agencies are encouraged to continually evaluate their progress toward network wide target speeds to 

ensure that long-term safety goals, such as those specified in the SHSP, are met. Speed management 

activities undertaken as part of the Safe System Approach may also be iterative and incremental 

in nature. Some agencies choose to redesign select components of a roadway when Safe System 

principles cannot be achieved in the current stage of implementation. Some agencies set incremental 

target speeds when operating speeds are substantially higher than the desired target speeds (FDOT 

2022). Others may install traffic signals that separate some road users in time even if full separation 

in space would be more effective (ITE 2020). This approach can still provide a benefit because each 

incremental improvement is a progressive investment towards the final Safe System (Corben 2020).

This stepwise approach may be more effective than high-cost infrastructure changes that do not 

progress towards Safe System outcomes because those reconfigurations may not properly address 

roadway risks related to speed. These types of improvements will require significant investment 

later to address the true sources of risks and will likely require a complete redesign. For example, 

if there is an intersection that requires a roundabout to be Safe Systems aligned and traffic signals 

are installed instead, to still align it to a Safe System Approach, the traffic lights might need to be 

removed later and a roundabout installed.

The remainder of this section briefly discusses the following:

• Monitoring and data collection

• Evaluation of speed management programs

• Speed enforcement

• Education of road users

• Useful technologies
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3.5.1. Monitoring and Data Collection

It is critical that agencies collect data after the implementation of speed management countermeasures 

to ensure that the effectiveness of those countermeasures can be evaluated. Data collection is also 

important for discerning the applicability of different treatments and for getting public support 

for those countermeasures. A city may learn that a specific speed management countermeasure, 

such as roundabouts, may help produce target speeds and reduce total crash severity but may have 

unexpected safety consequences, such as increased crash severity for pedestrians and in certain 

contexts (Khan and Habib 2022). Agencies should continue to monitor crash and speed data 

after implementation of countermeasures to discern what these unexpected effects may be so that 

additional treatments can be identified, if needed.

Ongoing data collection can also be important for maintaining a vision for speed management 

within a jurisdiction. After the City of Seattle updated its speed limit policy as part of its Vision 

Zero program, the city collected data on several corridors to ensure that the changes in speed limit 

signs were producing the desired target speeds. Seattle found that not only had 85th percentile 

speeds on the study corridors decreased, but injury crashes had also decreased by at least 10 percent 

on each corridor (City of Seattle 2020). Seattle was able to produce these findings and demonstrate 

to the public that its Vision Zero program and connected speed management activities are making 

the roads safer for all road users. This data collection also allows Seattle to provide feedback to 

road users regarding target speeds and allows them to promote these target speeds so that road users 

expect consistently low speeds as new projects are developed. Ongoing data collection has been 

pivotal for the City of Seattle’s success.

3.5.2. Evaluate Current Speed Management Efforts

Monitoring and evaluating speed management programs helps road authorities determine the 

effectiveness of these programs. Monitoring and evaluation can also be used to perform the 

following activities:

• Demonstrate the extent to which road authorities are achieving their Safe System goals

• Improve decision making for future programs

• Determine locations where additional interventions may be required to improve compliance with 

safe and appropriate speeds (i.e., improve levels of speed limit compliance)

• Demonstrate the safety benefits of speed management programs to the public

In addition to the data types discussed for analysis and evaluation in Section 3.2.2, practitioners 

often collect behavioral data after projects are completed to ensure that the desired speed and safety 

goals have been achieved. These additional data types may include the following:

• Awareness of speed management

• Perceptions of speed management activities

• Road user counts and latent demand (e.g., trips through new, slower roadway segments)

• Road user behavior (e.g., yielding)
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Agencies can collect these data using public surveys mailed to residents who live near project 

locations (or commuters who use those segments), through intercept surveys on those segments, 

through counts taken before and after project implementation, and through evaluations of recorded 

video data. These types of data can lend context to other objective measures of efficacy (e.g., crash 

and speed data) and can help agencies understand how the public perceives these projects in case 

modifications need to be made or the benefits need to be more successfully communicated.

3.5.3. Speed Enforcement

Enforcement is often vital for establishing initial driver compliance with target speeds. However, 

as discussed in Section 2.3, operating speed and driver behavior are intrinsically linked to roadway 

design. Drivers select their speeds based on the prevailing conditions of the roadway environment, 

and research has demonstrated that speed enforcement may be less effective at producing longterm changes in speed behavior when compared to other speed management techniques (Sanders, 

Judelman, and Schooley 2019). Speed behavior can vary in proximity to even speed safety 

cameras, so ongoing data collection is necessary to determine if and how to apply enforcement as a 

component of a speed management effort (Decina, Thomas, Srinivasan, and Staplin 2007).

Speed safety cameras can be highly effective, as illustrated in the Montgomery County, Maryland, 

case study in the Appendix. Montgomery County initiated an automated speed enforcement 

program in 2007 and has integrated this program within its Vision Zero plan. In this example, 

automated speed enforcement is used to support roadway design to create a culture of compliance 

with target speeds. The Montgomery County application is notable because the cameras are 

installed on a corridor basis and serve as a systemic treatment that enhances the County’s speed 

management program. Evaluations of this program have linked it to a 62 percent reduction in the 

likelihood that a vehicle will travel at more than 10 mph above the speed limit and a 19 percent 

reduction in the likelihood that a crash will result in a serious or fatal injury. The County intends to 

integrate its automated speed enforcement program with other speed management efforts as part of 

its Vision Zero work plan (Montgomery County Department of Police 2022).

 For more information on Montgomery County’s automated speed enforcement 

program and how the County integrated speed safety cameras with their Vision Zero 

program, see Appendix A.4.

Other agencies have also reported benefits from the installation of speed safety cameras. New York 

City reports that its camera program, installed in 750 school speed zones, corresponded to a 

72 percent drop in speeding behavior in school zones from 2014 to 2020 (City of New York 2020). 

The City and County of San Francisco (2015) examined speed safety camera practices across 

the United States and reported that speed safety camera programs have the benefit of addressing 

speeding violations more efficiently than traditional police enforcement programs. The City and 

County of San Francisco’s report also concluded that speed safety camera programs are effective 

at reducing speeds and crashes when used as part of larger speed management programs (2015). 

Finally, international literature supports the reported safety benefits of camera programs. Li et al. 

(2020) examined 464 speed cameras at sites across England and analyzed the efficacy of multiple 

camera installations for reducing crashes. The researchers concluded that speed cameras are most 

effective at a radius of 200 m (approximately 656 ft). However, when multiple cameras are installed 

within that radius, injury crashes may be reduced by 21.4 percent, a significant difference when 

compared to a reduction of 13.2 percent when only a single camera is installed.
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Agencies considering implementing speed enforcement as part of their speed management 

programs should consider two key parameters: safety and equity. First, the purpose of a speed 

safety camera program should be to improve roadway safety. Road users must believe that 

cameras are located for their benefit and without profit incentive. Second, any speed enforcement 

program should be carefully considered in terms of equity and potential benefit. Even automated 

speed enforcement, with its potential for unbiased deployment, may still inadvertently harm some 

communities if not sited in conjunction with roadway design considerations (Sutton and Tilahun 

2022). Equity must always be considered in the application of any type of enforcement, as Black 

and Indigenous communities often bear the brunt of enforcement activities. Whenever possible, 

agencies should consider alternatives to speed enforcement to produce target speeds.

3.5.4. Education of Road Users

Much of this report has focused on stakeholders creating a shared vision for speed management, 

but this vision should also include road users. As part of ongoing efforts to achieve target speeds, 

agencies should strive to create social norms around safe speeds and safe road use to maintain 

public support. The Safe System Approach emphasizes that the responsibility to prevent fatalities 

and serious injuries on roadways is shared by all stakeholders, so agencies implementing a Safe 

System Approach for Speed Management should be transparent and positive when crafting a vision 

for speed management.

One method for educating road users and traffic safety stakeholders about target speeds is to 

explicitly engage in communication activities related to traffic safety culture. It is critical that 

agencies communicate the benefits of speed management (see the City of Seattle Case Study in the 

Appendix) to ensure that drivers internalize the benefits of reduced speeds, including walkable and 

bikeable communities, health benefits, reduced stress, and reduced crashes for all. To increase public 

awareness of the potential of safe roads, the Safe Systems Consortium recommends practitioners 

develop and conduct Vision Zero/Safe System awareness campaigns that are culturally sensitive and 

based on evidence (Johns Hopkins University, ITE, and the FIA Foundation 2021).

A proactive safety culture in transportation can be achieved when road users actively go beyond 

what is legally required of them (Finley, Otto, Ward, and Arpin 2019). This can include surpassing 

legal obligations when making decisions that impact their own safety; for example, not traveling 

over 19 mph in high density pedestrian areas, even though this might be legally allowed. However, 

it can also mean influencing others in a manner that encourages them against engaging in unsafe 

activities. An example of this could be where friends prevent each other from speeding or remind 

each other to buckle up.
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Studies have shown that people in the United States engage in some measure of basic safety 

behavior on the road. However, a minority of people don’t engage in such behavior and therefore 

contribute a higher crash risk to the system. Proactive safety culture applies the Safe System 

Approach to creating redundancy by leveraging safer driving behaviors by the majority of users to 

compensate for noncompliant and unsafe behaviors from a minority of drivers. Agencies can seek 

to implement social norms around safe road use, such as engagement with communities, marketing, 

teaching at schools, encouraging workplace policies around safe driving, and encouraging 

discussions between law enforcement and the public (Finley, Otto, Ward, and Arpin 2019).

3.5.5. Useful Technologies

Agencies are encouraged to monitor ongoing research around the Safe System Approach and 

potentially beneficial technologies—such as connected infrastructure or automated systems—

for application within a speed management program. Transportation technology is developing 

rapidly, and FHWA frequently updates its Proven Safety Countermeasures with the latest 

innovations. Agencies are encouraged to review this page to identify new methods for speed 

management, and, if implemented, to collect data on those methods so that the public can be 

educated on their uses and best practices can be shared.

3.5.6. Examples of Monitoring, Evaluation, and Adjustment

The fifth stage of the Safe System Approach for Speed Management framework is for agencies to 

conduct monitoring, evaluation, and adjustment activities to determine whether existing speed 

management activities are working appropriately, or further countermeasures are needed. As 

mentioned, speed behaviors can migrate across a network as drivers adapt to corridor-specific 

changes, and some countermeasures may be less effective than expected. Additionally, speed 

limit changes may not always cause decreases in speed if roadway environments themselves 

are not modified or if the social norms surrounding speeding behaviors continue, so agencies 

may need to assess the efficacy of their speed management programs and be open to making 

necessary adjustments.

Several case studies in the Appendix of this report discuss evaluation and monitoring efforts 

agencies may undertake to determine the efficacy of their programs. One example of an important 

evaluation is New York City DOT’s before-after analysis of its speed safety camera program to 

determine if the countermeasure had an impact on speeding near school zones. New York City 

compared speeds from 2014 to 2020 and determined that the camera program had produced a 

72 percent decrease in speeding behavior near school zone camera locations. New York City 

also evaluated the effects of its speed hump and speed cushion installations to determine if these 

countermeasures had actually reduced speeds following implementation and reported a 17 percent 

reduction in injuries at nine speed cushion sites in 2021 compared to 2017. More information on 

how New York City DOT conducted its before-after evaluations can be found in Case Study A.5.
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To conclude the example from Section 3.4.6, an agency may continue monitoring operating speeds 

on all urban core roadways treated with speed limit reductions, speed feedback signs, and road diets. 

This ongoing monitoring should include operating speeds and should be conducted over several 

years to avoid a regression to the mean in both crashes and driver speeds. If the example agency 

cited in Section 3.4.6 were to discover, for example, that drivers on the roadways where speed 

feedback signs had been installed were once again driving above the target speed of 25 mph six 

months after the installation of those signs, the agency may need to determine whether additional 

changes to roadway design, such as bulb-outs or speed safety cameras, would be appropriate to 

reduce operating speed back to target speeds. Without this type of post-installation data collection, 

the agency may be unable to properly diagnose changes in speed problems or determine if its 

speed management activities remain effective. Therefore, any agencies undertaking a Safe System 

Approach to Speed Management should consider collecting speed and safety data through all parts 

of the program’s lifespan and use these data to make appropriate programmatic changes.
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4. CONCLUSION

Speeding, exceeding the posted speed limits, or traveling too fast for conditions was a contributing 

factor in almost 29 percent of all fatalities in 2021. Of the 42,939 fatalities that occurred on our 

Nation’s roadways that year, 12,330 were speeding-related—an increase of 7.9 percent from 

2020 (Stewart 2023). Speed directly influences the severity of traffic crashes because the laws 

of physics dictate that energy released in a crash is directly proportional to the velocity of the 

vehicle(s) involved. Therefore, speed management is one of the most important components of a 

Safe System Approach to traffic safety, and any effort toward achieving zero fatalities and serious 

injuries must be centered on keeping speeds at levels that account for human injury tolerance.

To address this critical issue of speed, U.S. DOT’s National Roadway Safety Strategy urges all 

agencies to adopt the Safe System Approach, a new paradigm in traffic safety management that 

emphasizes that humans have physiological tolerances to crash forces and that road agencies must 

create roadways that provide safe speeds and create redundancies to reduce the severity of crashes 

when they do occur (USDOT 2022a).

This report presented a framework to aid both State and local transportation agencies to develop a 

Safe System Approach for Speed Management. This framework consists of the following five stages:

1 Establishing a vision and building consensus for speed management

2 Collecting and analyzing speed and safety data

3 Prioritizing locations for speed management proactively

4 Selecting speed management countermeasures

5 Ongoing monitoring, evaluation, and adjustment

Not every agency will be able to apply every countermeasure discussed throughout this report, and 

not all agencies will be able to easily adjust posted and statutory speed limits. However, this report 

provides case studies that demonstrate how agencies have been able to overcome institutional 

barriers and rally behind Safe System principles to enact speed management programs with proven, 

measurable reductions in operating speeds and fatal and serious injury crashes.

Readers are encouraged to review the 10 case studies to find examples of successful approaches 

to lowering speed limits, redesigning roadways, collecting data, enforcing speeds with 

technologies, and working toward network-wide realizations of target speeds that improve the 

safety of all road users.
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Across the international and domestic documents reviewed for this report and collected through 

interviews with case study jurisdictions, some key themes emerged, including the following:

• As possible, agencies should attempt to align speed limits and target speeds that prioritize 

injury minimization, and this alignment often requires changing the roadway environment to 

slow driver speeds.

• Agencies can use strategic plans, like Vision Zero, to build public will for speed management 

practices and align those practices with Safe System Approach-based traffic safety goals.

• Agencies should collect relevant speed and safety data to both guide the speed management 

program and to build public support for the program.
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APPENDIX – CASE STUDIES

Case Study A.1. Washington State Injury Minimization and Speed 

Management —State of Washington, USA

Key Successes

The Washington State Injury Minimization and Speed Management effort is a noteworthy practice 

that shows an example of a State DOT setting a framework for speed management in jurisdictions.

The Safe System Approach Highlights

• Death/serious injury is unacceptable: Washington adopted a Target Zero plan in 2019 with 

the goal to eliminate road fatalities and serious injuries by 2030.

• Humans make mistakes/humans are vulnerable: Injury minimization is a priority in the 

State’s Target Zero efforts.

• Responsibility is shared: Interagency collaboration and collaboration with neighboring 

jurisdictions help to achieve speed management and injury minimization.

• Redundancy is crucial: Speed management and injury minimization are achieved through 

engineering, education, and enforcement measures.

Background

In 2019, Washington State adopted the Safe System Approach as part of its SHSP, which embraced 

the Zero Deaths vision.1 Speed management is a priority in Washington’s Zero Deaths vision, 

since one in every three fatal crashes in the State between 2015 and 2017 involved speeding as 

a contributing factor. The plan recognized that speed limit setting through the notion of injury 

minimization would result in a significant reduction in fatal and serious injuries for all road users, 

especially pedestrians and bicyclists.

As a result of Washington’s Vision Zero efforts, the Washington State Department of Transportation 

(WSDOT) convened a workgroup including State, local, and Tribal partners to develop a speed 

management policy and guidelines focused on injury minimization. The policy elements and 

implementation recommendations were summarized in a document released in October 2020,2

which emphasizes lower operating speeds based on context on State routes, city streets, county 

roads, and Tribal roads and that are compatible with the needs of all types of users. The WSDOT 

workgroup encourages all agencies in the State of Washington to adopt an injury minimization and 

speed management policy based on the elements outlined in the document.

1 State of Washington. (2019). Washington State Strategic Highway Safety Plan 2019: Zero Deaths and Zero Serious Injuries 

by 2030. Olympia, WA: State of Washington. Retrieved from http://wtsc.wa.gov/wp-content/uploads/dlm_uploads/2019/10/

TargetZero2019Lo-RES.pdf.

2 Washington Department of Transportation. (2020). Washington State Injury Minimization and Speed Management 

Policy Elements and Implementation Recommendations. Olympia, WA: State of Washington. Retrieved from https://wsdot.

wa.govsitesdefault/ files/2021-10/InjuryMinimization-SpeedManagement-PolicyElements-Recommendations.pdf.
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Implementation

The WSDOT Injury Minimization and Speed Management workgroup studied the findings of 

multiple reports, scientific papers, legislative statutes, manuals, and recommendation documents 

to understand and address speed and injury severity. Based on the findings, the workgroup 

recommended the following elements for an Injury Minimization and Speed Management Policy 

for all agencies in Washington:

• Adopt and implement an injury minimization speed limit setting approach.

• Adopt a broader Safe System Approach to proactively identify priority locations (locations 

with higher possibility of serious injury or fatal crashes).

• Consider injury minimization and speed management in all transportation investments and 

project phases regardless of funding source.

• Collaborate with neighboring jurisdictions.

• Require training on injury minimization and speed management techniques.

• Adopt access control, access management policies, and land use development policies, 

ordinances, and practices that consider target speeds.

• Adopt a Vision Zero goal.

The Injury Minimization and Speed Management workgroup also provided recommendations to 

achieve target speeds for practitioners who set speed limits, design engineers, and planners. The 

workgroup recommended that the process for setting target speeds be an innovative practice that 

considers the presence of older adults, transit users, youth, pedestrians, bicyclists, and land use. 

Special consideration is provided for road users who are reliant on transit and active transportation 

due to income disparities or physical disabilities. A summary of the recommended process to set 

target speed limits is shown below:

• Establish target speeds based on road and land use context, road user characteristics, potential 

for different crash types, the impact forces that result from a crash, and the human body’s 

injury tolerance. This may require a phased, step-down approach.

• Use default/category target speed limits for all areas that have the same context, density, and/or 

road characteristics.

• Where the operating speed is within 5 mph of the target speed, adopt the target speed.

• Where the operating speed exceeds the target speed by 5 mph, use an engineering study to 

determine iterative speed limits and implement speed management approaches.

• Make incremental adjustments of 5 mph or more as motorists respond to speed management 

techniques until the target speed is achieved.

In addition to the overall recommendations for injury minimization and speed management in 

Washington, the workgroup also developed specific information regarding data analysis, education 

of the public and elected officials, changes to laws and regulations, and enforcement. The 

workgroup recommended that traffic safety professionals pursue training at all jurisdictional levels 

in engineering, education, and enforcement.
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Outcomes

Although no evaluation of the speed and safety impacts of the injury minimization and speed 

management recommendations are available, this effort is a noteworthy practice for setting a 

framework for speed management in jurisdictions.

Additional Information

Setting target speed limits based on factors other than vehicular travel speeds is an emerging 

approach. On March 25, 2022, Washington State Governor Jay Inslee signed into law Senate Bill 

5974.3 Section 418 of this law states that all State transportation projects starting the design phase 

on or after July 1, 2022, and that are valued at more than $500,000 must 

adjust the speed limit to a lower speed with appropriate modifications to roadway design 

and operations to achieve the desired operating speed in those locations where this speed 

management approach aligns with local plans or ordinances, particularly in those contexts 

that present a higher possibility of serious injury or fatal crashes occurring based on land use 

context, observed crash data, crash potential, roadway characteristics that are likely to increase 

exposure, or a combination thereof, in keeping with a Safe System Approach and with the 

intention of ultimately eliminating serious and fatal crashes.

The law also made several amendments to Washington State law regarding automated traffic safety 

cameras. For additional information regarding Injury Minimization and Speed Management in 

Washington, contact Charlotte Claybrooke, WSDOT Active Transportation Programs Manager, at 

claybrc@wsdot.wa.gov. 

3 State of Washington. (2022). Engrossed Substitute Senate Bill 5974. 67th Legislature. Retrieved from 

https://lawfilesext.leg.wa.gov/biennium/2021-22/Pdf/Bills/Session%20Laws/Senate/5974-S.SL.pdf.
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Case Study A.2. Video-Based Network-Wide Speed and Speeding 

Analysis—Bellevue, Washington, USA

Key Successes

The Video-Based Network-Wide Speed and Speeding Analysis project in Bellevue, Washington, 

developed a video-based network screening methodology to identify locations with high risk for 

vehicular speeding and improve the city’s understanding of the factors contributing to speeding at 

hot spots. This proactive approach allows the implementation of safety countermeasures before 

crashes occur.

The Safe System Approach Highlights

• Death/serious injury is unacceptable: Adoption of a Vision Zero resolution in 2015

• Humans make mistakes/humans are vulnerable: Efforts to understand contributing factors to 

reduce speeding-related fatalities and serious injuries

• Responsibility is shared: Collaborative approach between the City of Bellevue, Transoft 

Solutions, Together for Safer Roads, and PacTrans – University of Washington

• Safety is proactive: Identifying crash contributing factors (such as speeding) citywide through 

video-based analysis of near-misses to improve safety conditions before crashes occur

• Redundancy is crucial: Data collection, engineering measures, and enforcement to reduce 

speeding in Bellevue

Background

The City of Bellevue is in the Eastside region of King County and is the fifth largest city in 

Washington, with a population of approximately 152,000.1 Bellevue adopted a Vision Zero 

resolution in 2015 with the goal of eliminating fatalities and serious injuries on City streets by 

2030.2 The city’s focus has been to understand the factors contributing to these fatalities and serious 

injuries and develop effective countermeasures.

The city partnered with Transoft Solutions (formerly Brisk Synergies), Together for Safer Roads, 

and PacTrans – University of Washington to conduct a network-level analysis of traffic camera 

video data to identify locations with high risk of crashes based on near misses. The project used 

video footage from Bellevue’s network of existing traffic cameras, which was processed and 

analyzed using Transoft Solutions’ traffic and road safety technology.3

1 United States Census Bureau. (2020). “2020 Census.” Retrieved from https://www.census.gov/programssurveys/decennial-census/decade/2020/2020-census-main.html.

2 City of Bellevue. (2015). “Resolution No. 9035: A Resolution Endorsing Vision Zero.” Retrieved from 

https://bellevue.legistar.com/LegislationDetail.aspx?ID=2529869&GUID=AC438708-5B2B-40BB-A155-

D41457B5DDEF.

3 City of Bellevue, Transoft Solutions, Together for Safer Roads, and PacTrans – University of Washington. 

(2020). Video-Based Network-Wide Speed and Speeding Analysis. Retrieved from https://safety.transoftsolutions.

com/resources/.
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Together for Safer Roads is a corporate social accelerator that leverages private sector technology, 

data, and expertise to prevent traffic crashes; the University of Washington was part of the team 

that had previously launched a pilot video analytics program in Bellevue and contributed to the 

project by sharing lessons learned. This project is one of three similar efforts conducted through this 

partnership; the other two are the Video-Based Network-Wide Conflict Analysis project4 and the 

Video-Based Conflict, Speeding, and Crash Correlation project.5

Implementation

The Video-Based Network-Wide Speed and Speeding Analysis in Bellevue was a large scale 

network screening project using video data from traffic surveillance cameras and TrafxSAFE 

(previously identified as BriskLUMINA), a specialized automated-road-safety platform developed 

by Transoft Solutions. The project evaluated 40 signalized intersections, mostly outside of the 

downtown area, including 34 four-legged intersections, 5 three-legged intersections, and 1 fivelegged intersection. The intersections were selected to represent different geographic locations, land 

uses, population density, and road geometry. All intersections have a posted speed limit of 30 or 

35 mph, except for the Bel-Red Road and NE 30th Street intersection, which had a 40-mph posted 

speed limit.

Traffic cameras at the study intersections recorded daily for 16 hours (from 6 a.m. to 10 p.m.) for 

the months of August and September in 2019. Road user counts, operating speeds, and near-miss data 

was derived from the processing of the video footage. To understand factors contributing to speeding, 

statistical models that included the following variables were developed by Transoft Solutions:

• Urban density (high or medium)

• Land use (commercial or residential)

• Presence of school within less than 0.125 miles from the intersection

• Road user types (car driver, bus or truck operator, motorcyclist)

• Road user movement (through, left turn, or right turn)

• Vehicular traffic phasing (protected vs. non-protected left turns)

• Pedestrian traffic phasing

• Traffic volumes

• Number of lanes

• Lane width

• Crosswalk width

• Presence of bike infrastructure (dedicated bike path, shared bike path, both, or neither)

• Time of the day

• Day of the week

4 City of Bellevue, Transoft Solutions, Together for Safer Roads, and PacTrans – University of Washington. 

(2020). Video-Based Network-Wide Conflict Analysis. Retrieved from https://brisk-cdn.s3.amazonaws.com/www/

articles/2020-07-05/VZ-ITS-Bellevue-Report-1-web.pdf. 

5 City of Bellevue, Transoft Solutions, Together for Safer Roads, and PacTrans – University of Washington. 

(2020). Video-Based Conflict, Speeding, and Crash Correlation. Retrieved from https://brisk-cdn.s3.amazonaws.

com/www/articles/2020-07-05/VZ-ITS-Bellevue-Report-3-web.pdf.
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Outcomes

The evaluation of video footage in Bellevue resulted in the following network-wide findings:

• Vehicular speed was higher in residential locations than in commercial locations.

• Vehicular speeds were higher at intersections outside of the downtown area.

• Vehicular speeds were higher on the weekend.

• Approximately 11 percent of drivers were speeding. Driver speeding incidence was higher in 

the downtown area.

• Motorcyclists were the fastest motorized road users.

• There was a decrease in vehicular speeding during peak hours.

• The video-based network screening allowed the development of a map showing the percentage 

of motorists speeding (Figure 4).

 Source: City of Bellevue, Transoft Solutions, Together for Safer Roads, and PacTrans.

Figure 4. Percentage of motorists speeding.

An in-depth analysis was conducted at the intersection of Bel-Red Road and NE 30th Street, the 

study intersection most prone to vehicular speeding. The four-legged intersection includes a small 

traffic island separating the westbound right-turning movements and another island for southbound 

left-turning drivers. No northbound left-turn, eastbound left-turn, eastbound through, and westbound 

through movements are permitted at the intersection (Figure 5). In addition, pedestrian volumes are 

low at the intersection.
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

Source: City of Bellevue, Transoft Solutions, Together for Safer Roads, 

and PacTrans – University of Washington.

Figure 5. Bel-Red Road and NE 30th Street 

in Bellevue.

Source: City of Bellevue, Transoft Solutions, Together for 

Safer Roads, and PacTrans – University of Washington.

Figure 6. Speed heatmap at the Bel-Red 

Road and NE 30th Street intersection.

The analysis of the Bel-Red Road and NE 30th Street intersection, which had the highest risk for 

motorist speeding, resulted in the following insights:

Northbound and southbound through speeds were high (Figure 6). Only two through movements 

are allowed at this intersection, which are along the North-South corridor, where traffic volumes 

are significantly higher. Additionally, only one left turn is permissible along this corridor, and it is 

protected by a traffic island. Speeding at this intersection can be attributed to the excessive confidence 

of drivers because of the lower volumes of surrounding movements and the prohibition of several 

other movements. The speeding behavior is similar to that of drivers increasing their speeds to catch 

the end of a green or yellow traffic light (Figure 7).

 Source: City of Bellevue, Transoft Solutions, Together for Safer Roads, and PacTrans – University of Washington.

Figure 7. Through driver speeding to cross red light.

High-Speed Traffic
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

All right turning movements had similar speeds except for the northbound right-turning movement. 

This can be attributed to the wider turning radius available for this movement compared to the other 

right-turning movements.

The Video-Based Network-Wide Speed and Speeding Analysis demonstrates the scalability of 

the network screening methodology to identify locations with high risk for vehicular speeding 

and understanding factors contributing to speeding at hot spots. This approach allows the 

implementation of safety countermeasures before crashes occur, and this analytics solution can 

support Vision Zero programs. The City of Bellevue plans on implementing safety countermeasures 

at high- risk locations identified with this network screening methodology in the near future.

Additional Information

In addition to the Video-Based Network-Wide Program to identify speeding contributing factors, 

the City of Bellevue has several speed management programs. The city has slowly started rolling 

out 20 mph neighborhood speeds through its Neighborhood Slow Zone program and recently 

updated its Standard Operating Procedures for evaluating existing speed limits based on the latest 

information from NCHRP and NACTO. The city’s Neighborhood Traffic Safety Services group 

works with residents to discourage speeding near schools by installing permanent speed feedback 

signs and school zone flashing beacons in the vicinity of schools. To support speeding concerns in 

neighborhoods, the city has a program that allows residents to request temporary speed feedback 

signs, special police speed enforcement, use of a radar gun to do an evaluation of speed concerns, 

and lawn signs that encourage safe speeds. For additional information, contact Franz Loewenherz, 

City of Bellevue Mobility Planning and Solutions Manager, at Floewenherz@bellevuewa.gov.
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

Case Study A.3. 2020 Vision Zero: Speed Management—Fremont, 

California, USA

Key Successes

The city of Fremont, California, adopted a Vision Zero policy in 2015. Fremont’s efforts to reduce 

vehicular speeds resulted in the following safety outcomes (comparing average crashes between 2013 

to 2015 with average crashes between 2018 and 2020):

• A 45 percent decrease in fatal and serious injury crashes across all modes

• A 44 percent decrease in crashes involving speeding

The Safe System Approach Highlights

Examples of how elements of the Safe System Approach are incorporated in the Fremont Vision 

Zero policy are shown below:

• Death/serious injury is unacceptable: The city adopted a Vision Zero policy in 2015.

• Humans make mistakes/humans are vulnerable: The policy focuses on reducing vehicular 

speeds to lower crash impact forces.

• Responsibility is shared: Vision Zero is a coordinated effort that involves the City of Fremont 

Public Works Department, the city manager, the community, the police department, local 

advocates, educational institutions, and elected officials.

• Safety is proactive: The policy used a systemic approach to implement speed limit reduction, 

enforcement, and to reduce vehicular travel-lane width.

• Redundancy is crucial: Engineering (street redesign), enforcement, and education 

(community outreach) measures are part of Fremont’s efforts to reduce vehicular travel speeds.

Background

The City of Fremont is located in the Silicon Valley area of Northern California and has a 

population of 240,000. From 2013 through 2015, Fremont experienced a concerning rise in traffic 

fatalities and serious injury crashes. The city’s organizational focus on traffic safety began in 2015 

with the adoption of a Vision Zero policy, followed by an action plan in 2016.1 Prior to 2015, 

70 percent of fatal and serious injury crashes in Fremont happened on streets with a speed limit of 

40 mph or higher.

City staff from the Police Department and the Public Works Department prepared a data-driven, 

fully collaborative action plan for year 2020. As part of the effort to eliminate fatal and serious 

injury crashes, the City of Fremont has applied a Safe System Approach to street design, operations, 

and public education.

1 City of Fremont. (2017). Fremont Vision Zero 2020:. Retrieved from https://mtc.ca.gov/sites/default/files/

Fremont_Vision_Zero.pdf.
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

Implementation

Fremont’s approach to Vision Zero includes modifying organization practices, forming 

partnerships, using data for high-impact work, updating plans and community engagement, 

and implementing safety improvements. The City of Fremont’s Transportation Engineering, 

Pavement Maintenance Program, and Street Maintenance are all organized within the public works 

department, which reduces barriers to collaboration. Further, the collaboration between the police 

department, fire department, and public works department resulted in the following:

• Crash locations and near miss locations are evaluated for countermeasures.

• Project planning and design of streets is collaborative to ensure emergency response times are 

not affected.

The City of Fremont Public Works Department conducts data analysis that includes regular 

and timely monitoring of detailed crash narratives and reports (in coordination with the police 

department), mapping of the high-injury network, and recommending both hot spot and 

systemic countermeasures. Community engagement occurs through task forces before any safety 

improvements are implemented. The city’s actions to reduce vehicular speeds and improve safety 

are summarized below:

• Safe and Complete Streets: Fremont has adopted a 10 ft travel lane standard, which creates a 

feeling of greater enclosure and friction for drivers and encourages slower speeds. Since 2015, 

the City of Fremont restriped approximately 50 percent of its arterial roadways, reducing lane 

widths from 12–14 ft to 10 ft (Figure 8).

Source: City of Fremont.

Figure 8. Striped median to reduce lane widths in Fremont.

• Safe neighborhoods: Fremont has undertaken measures to ensure safe speeds in 

neighborhoods. The city increased the number of speed humps from 200 to 250 citywide 

between 2018 and 2020.
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

• Speed management: After engineering streets for safer speeds, the City of Fremont re-surveys 

streets to assess whether projects resulted in lower operating speeds. Fremont has lowered the 

posted speed limit on more than 50 street segments, comprising more than 20 roadway miles.

• Community outreach: The City of Fremont has launched a “Drive Slowly, Be Healthy” 

campaign to manage speeds during the national events of 2020 and beyond. The campaign 

includes 20 mph advisory speeds on all neighborhood streets.

• Hot spot response: In addition to implementing systemic improvements (e.g., quick-build 

crosswalk improvements and installation of pedestrian countdown signals) to prevent future 

crashes, Fremont implemented improvements in response to crash hot spots. For example, 

Grimmer Boulevard was a hot spot for fatal and serious injury crashes before 2016. The 

city restriped the roadway with narrower 10 ft lanes and a buffered bike lane and installed a 

concrete k-rail in the bike buffer.

Outcomes

The City of Fremont conducted speed surveys on approximately 100 street segments citywide in 

2020, in advance of its typical 7-year cycle for citywide speed surveys. In 2021, the city released 

a safety status report comparing average crashes between 2013 to 2015 (before the Vision Zero 

policy) with average crashes between 2018 to 2020 (after the Vision Zero policy).2

 Impacts on 

crashes included a 45 percent reduction in the number of fatal and serious injury crashes across 

all modes and a 44 percent decrease in total crashes involving speeding. In addition, no fatal and 

serious injury crashes have occurred along Grimmer Boulevard—previously a hot spot—since the 

safety improvements were installed.

Additional Information

The City of Fremont achieved its Vision Zero accomplishments with no new city funding 

commitments and no new dedicated staff positions. The program entailed reallocating existing 

funding resources away from projects that did not serve Vision Zero goals and shuffling existing 

staff assignments. The City of Fremont redirected $2.5 million in funding that was not aligned with 

the “safety first” policy, which allowed work to start immediately rather than be delayed by the 

regular budget allocation process.

The City of Fremont’s next plan includes actions such as encouraging State legislation for safer 

speeds by enabling speed safety cameras, as well as continuing local actions for safer streets by 

managing speeds using signal timing and enforcement. For additional information, contact Hans 

Larsen, City Public Works Director (hlarsen@fremont.gov).

2

 City of Fremont, CA. (2021). Fremont Vision Zero: Status Report + 2025 Action Plan. Retrieved from: https://

www.fremont.gov/home/showpublisheddocument/759/637750212463000000.
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

Case Study A.4. Automated Speed Enforcement—Montgomery County, 

Maryland, USA

Key Successes

The effects of the automated speed enforcement in Montgomery County, Maryland, resulted in the 

following outcomes:

• A 100 percent reduction in mean speeds due to the speed cameras.

• A 62 percent reduction in the likelihood that a vehicle was traveling more than 10 mph above 

the speed limit at camera sites.

• A 19 percent reduction in the likelihood that a crash resulted in fatality or serious injury due 

to speed cameras alone. Along the speed camera corridors (cameras were periodically moved 

along the length of a roadway segment), speed cameras were associated with an additional 

30 percent reduction in the likelihood that a crash resulted in a fatality or serious injury.

The Safe System Approach Highlights

• Death/serious injury is unacceptable: Montgomery County adopted Vision Zero in 2016.

• Humans make mistakes/humans are vulnerable: The county’s automated speed 

enforcement program focuses on vehicular speed reduction, which can lead to reduced crash 

severity, especially for vulnerable road users.

Background

Montgomery County is the most populous county in the State of Maryland, with a population of 

approximately 1 million. The County has multiple programs aimed at lowering operating speeds 

to match the roadway and land use context, including their Safe Speed Program (automated speed 

enforcement). Placement of automated traffic cameras are legislated under Maryland Traffic Article 

21-809.1 Automated speed enforcement in Montgomery County was implemented in 2007. In 

2009, the State speed camera law increased the enforcement threshold from 11 to 12 mph over 

the speed limit and restricted school zone enforcement hours. In 2012, Montgomery County 

began using a corridor approach, in which cameras were periodically moved along the length of a 

roadway segment.

Implementation

The county introduced automated speed enforcement in 2007, and early research found that more 

than 60 percent of residents supported the program after it started.2

 In Montgomery County, local 

law enforcement can place speed cameras on a residential road with a speed limit of 35 mph or less 

or within a designated school zone.

1

 Montgomery County. (2022). “Speed Camera Placement.” Retrieved from https://www.montgomerycountymd.

gov/ pol/howdoI/request-speed-camera.html.

2

 Insurance Institute for Highway Safety. (2008). Evaluation of Automated Speed Enforcement in Montgomery 

County, Maryland. Retrieved from https://safety.fhwa.dot.gov/speedmgt/ref_mats/fhwasa1304/resources/

Evaluation%20of%20ASE%20in%20Montgomery%20County,%20MD.pdf.
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

The process for placing and evaluating speed cameras in Montgomery County uses a data-driven 

approach. The process for installing speed cameras in the county follows the following steps:

1. Identify camera location: The request to initiate evaluation for speed camera installation can 

be made by residents, homeowners associations, police officers, government officials, and police 

department traffic division personnel. Potential camera locations can also be identified based on 

crash data, site surveys, pedestrian activity, community and environmental concerns, and points 

of interest in the area.

2. Data collection: Vehicular speeds are collected along stretches of the roadway with speeding 

concerns.

3. Data analysis: Data is analyzed and reviewed by automated traffic enforcement unit personnel, 

the safe speed program manager, and the director of the police department’s traffic division.

4. Field observations: After a potential location for camera installation is identified, a field 

visit is conducted to evaluate the following site characteristics: location (residential, school 

zone, or commercial), roadway grade, presence of speed limit signs, crash frequency, traffic 

volumes, environmental factors (areas where the equipment can be safely set up, operated, 

and maintained), pedestrian proximity to a potential speed enforcement location (existence of 

schools, bus stops, playgrounds, pools, sidewalks, retirement facilities, crosswalks, and other 

pedestrian generators).

5. Final approval: The director of the traffic division has final approval. Once final approval is 

given, the site must be advertised in a newspaper of general circulation prior to conducting 

enforcement.

 Source: Montgomery County.

Figure 9. Montgomery County safe-speed camera locations 

(outside of Speed Camera Corridors).
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

As of 2019, there were 152 speed cameras (Figure 9) in Montgomery County.3The county 

constantly evaluates driver behavior near the speed camera locations. With the increased driver 

familiarity with camera locations, Montgomery County noticed that drivers generally slowed down 

when approaching a known speed camera and accelerated once they had passed it. To mitigate this 

driver behavior, the Montgomery County Police Department initiated a corridor approach in 2012, 

which allows for the placement of cameras anywhere within a designated speed camera corridor.4

The cameras along the speed camera corridor change locations regularly. The county adopted the 

speed camera corridor approach to have drivers reduce speeds on an entire stretch of road rather 

than just where they know the cameras are located.

Outcomes

A study conducted in 2016 evaluated the effects of automated speed enforcement in Montgomery 

County on vehicle speeds, public opinion, and crashes.5

 The study found that speed cameras were 

associated with a 10 percent reduction in mean speeds. The study also found a 62 percent reduction in 

the likelihood that a vehicle was traveling more than 10 mph above the speed limit at camera sites.

Further, the overall effect of the camera program in its modified form was a 39 percent reduction 

in the likelihood that a crash would result in an incapacitating or fatal injury. Speed cameras alone 

were associated with a 19 percent reduction in the likelihood that a crash would result in fatality or 

serious injury. At the speed camera corridors, where cameras would be moved so that people did not 

slow for only one location, speed cameras were associated with an additional 30 percent reduction 

in the likelihood that a crash resulted in a fatality or serious injury.

Additional Information

Montgomery County adopted Vision Zero in 2016 with the goal of eliminating fatal and serious 

injuries on county roads by 2030. Under the Vision Zero 2030 Action Plan, work plans are updated 

every even year to make continual progress on all action items. The 2022-2023 Vision Zero work 

plan includes the following safe speeds action items: examine speed limit on all projects, speed 

management policy, and enforcement of speed limits.6 For further information regarding speed 

enforcement in Montgomery County, contact Captain Jim Brown, Montgomery County Traffic 

division director, at POLTrafficDivisionDirector@montgomerycountymd.gov.

3

 Montgomery County. (2019). Safe Speed Camera Locations. Retrieved from https://www.

montgomerycountymd.gov/pol/howdoI/speed-camera-locations.html.

4

 Montgomery County. (2022). Speed Camera Corridor Camera Locations. Retrieved from https://www.

montgomerycountymd.gov/pol/Resources/Files/speed-camera/SpeedCameraLocations2020.pdf.

5

 Hu W, McCartt AT. (2016). “Effects of Automated Speed Enforcement in Montgomery County, Maryland, on 

Vehicle Speeds, Public Opinion, and Crashes,” Traffic Injury Prevention 17(1):53–8. https://doi.org/10.1080/15389588.

2016.1189076.

6

 Montgomery County. (2022). Vision Zero: Fiscal Years 2022-23 Work Plan. Retrieved from https://www.

montgomerycountymd.gov/visionzero/Resources/Files/FY22-23_Vision_Zero_Workplan.pdf.
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

Case Study A.5. New York City’s Speeding Solutions Toolkit—New York City, 

New York, USA

Key Successes

New York City’s speed management toolkit uses a variety of approaches, including speed limit reduction, 

school zone automated enforcement, police enforcement, installation of speed humps and speed 

cushions, reduced vehicular travel lane widths, intersection turn calming, and community outreach. 

New York City’s efforts to reduce speeds and improve safety resulted in the following outcomes:

• Speeding at fixed camera locations in school zones has dropped 72 percent.

• Crashes with injuries, considering all road users, decreased by 8 percent on speed camera 

corridors in school zones.

• Injuries resulting from bicycle and pedestrian crashes with children decreased by 20 percent 

on speed camera corridors in school zones. 

• Injuries at speed-hump locations decreased by 9 percent.

• Injuries at speed-cushion locations decreased by 17 percent.

• Pedestrian fatalities and serious injuries decreased by 28 percent after road diet projects. 

• Pedestrian fatalities and serious injuries decreased by 33 percent after intersection turn 

calming improvements.

The Safe System Approach Highlights

• Death/serious injury is unacceptable: The city adopted Vision Zero in 2014.

• Humans make mistakes/humans are vulnerable: The city introduced speed reduction 

measures to reduce impact forces of a crash.

• Responsibility is shared: The effort entailed collaboration between New York City departments 

and local agencies and organizations.

• Safety is proactive: The approach enacted a citywide speed limit reduction.

• Redundancy is crucial: Engineering, enforcement, and education measures were adopted to 

reduce vehicular speeds.

Background

New York City adopted a Vision Zero policy in 2014, with a collaborative action plan involving 

the City Hall, Police Department, Department of Transportation, Taxi and Limousine Commission, 

Department of Citywide Administrative Services, and Department of Health and Mental Hygiene.1

At the time, road crashes in New York City resulted in approximately 250 fatalities and 4,000 serious 

injuries each year, and 70 percent of pedestrian fatalities involved driver behavior, such as inattention, 

speeding, and failure to yield. As a result, speed management was identified as a focus area for the 

city’s Vision Zero efforts, and a toolkit of speeding solutions was implemented to improve safety.

1

 City of New York. (2014). Vision Zero Action Plan. Retrieved from https://www.nyc.gov/html/visionzero/pdf/ nycvision-zero-action-plan.pdf.
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

Implementation

New York City’s Speeding Solutions Toolkit uses a variety of approaches, including speed cameras, 

installation of speed bumps, focused enforcement, signal reprogramming, reduced speed limits, and 

street redesigns.

• Speed limits: In 2014, New York City Department of Transportation (NYC DOT) reduced the 

citywide default speed limit to 25 mph and installed more than 5,000 new speed limit signs in 

combination with camera-based speed enforcement (Figure 10). Further, NYC DOT reduced 

the speed limit by 5 mph on more than 70 miles of arterial corridors.

• School zone automated enforcement: In 2013, New York State enacted Section 1180-b of 

New York State’s Vehicle and Traffic Law (VTL), which allowed New York City the authority 

to pilot an automated speed enforcement program in 20 school speed zones. New York City 

has since then enacted legislation to expand the use of automated enforcement and currently 

has speed cameras installed in 750 school speed zones. Camera installation is prioritized at 

locations with the highest incidence of speeding and serious crashes involving pedestrians. 

State law prohibits New York City from using the speed camera program to issue violations for 

speeding unless it is observed within a quarter- mile radius of a school building between the 

hours of 6 AM and 10 PM on a weekday.

• Police enforcement: Traditional speeding enforcement is also a tool to reduce vehicular travel 

speeds in New York City.

• Speed humps and cushions: New York City installed almost 2,200 speed humps and 40 speed 

cushions between 2014 and 2020.

 Source: City of New York.

Figure 10. Speed limit sign used in combination with automated enforcement.

• Street Improvement Projects (SIP) program: New York City’s SIP program prioritizes 

safety improvements at locations with high rates of serious pedestrian injuries and fatalities. 

Some of the program countermeasures are related to speed reduction, such as roadway redesign 

and turn calming (Figure 11). Roadway redesign is conducted by reducing vehicular travel 

lane width or converting a vehicular lane to use for pedestrians and cyclists. Turn calming is 

implemented by adding markings, plastic bollards, and/or rubber speed bumps that slow and 

control vehicular turns.
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

Source: NYC DOT.

Figure 11. Lincoln Center Bowtie Street improvements included reduced lane width and 

turn calming.

• Community outreach: Along the most crash prone corridors in New York City, the 

New York City Police Department (NYPD) and NYC DOT Street Teams combined education 

and enforcement. The NYC DOT Street Teams inform a specific community about safety and 

Vision Zero efforts while increased enforcement of traffic violations is conducted by NYPD.

• Education: NYC DOT public education campaigns have a particular emphasis on speeding 

and are disseminated through television, radio, billboards, and bus stop advertisements.

Outcomes

A before-after analysis was conducted to evaluate speeding and safety outcomes at fixed school 

zone camera locations in New York City between 2014 and 2020.2 The study found that speeding 

at fixed school zone camera locations dropped 72 percent. Further, the analysis showed a 3 percent 

reduction in total crashes and an 8 percent reduction in crashes with injuries, considering all road 

users. The study also showed that there was an approximately 20 percent reduction in injuries 

resulting from bicycle and pedestrian crashes with children.

Safety outcomes from installing speed humps and speed cushions were also investigated. A 

before-after analysisin New York City showed a 9 percent reduction in injuries at 1,637 speed 

hump locations (between 2008 and 2015) and a 17 percent reduction in injuries at 9 speed cushion 

locations (between 2017 and 2021).3

NYC DOT employed a before-after injury analysis comparing the average year of crash data before 

SIP treatment installation to the average year of crash data after installation, with a focus on 

pedestrian fatalities and injuries.4 The safety outcomes for speeding-related treatments are 

as follows:

2

 City of New York (2020). New York City Automated Speed Enforcement Program: 2014-2020 Report. 

Retrieved from https://www1.nyc.gov/html/dot/downloads/pdf/speed-camera-report.pdf.

3 Information provided by the New York City Department of Transportation for this case study.

4

 Ibid.
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

• Road diets: 28 road segments (29.12 miles) were evaluated and demonstrated a 28 percent 

reduction in pedestrian fatalities and serious injuries.

• Turn calming: The evaluation of 107 intersections before and after turn-calming treatments 

showed a 33 percent reduction in pedestrian fatalities and serious injuries.

Additional Information

From 2014 to 2020 (fiscal year), the speed camera program in New York City school zones had 

$155,779,314 in operating costs and $94,588,548 in capital costs. For more information regarding 

New York City’s speed management efforts, contact Rob Viola, Director of Safety Policy and 

Research at the NYC Department of Transportation, at RViola@dot.nyc.gov.
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

Case Study A.6. Multi-Disciplinary Approach for Speed Reduction 

Citywide—Portland, Oregon, USA

Key Successes

The multi-disciplinary approach for speed reduction citywide in Portland included strategies 

such as residential speed limit reduction, an alternative methodology to setting speed limits, street 

redesign, intersection left turn calming, automated speed enforcement, and community outreach and 

education. The key successes from the city’s efforts to reduce vehicular speeds are shown below:

• A 34 percent reduction in the odds of observing speeds greater than 30 mph on 

residential streets

• A 50 percent reduction in the odds of observing speeds greater than 35 mph on 

residential streets

• Development of an alternative methodology for setting speed limits in Portland that 

considers vehicles, pedestrians, and bicyclists

• Street redesign (Figure 12) resulted in a reduction in vehicle speeds with no significant 

changes to travel times along the main corridor and no significant changes to volumes 

or speeds on nearby neighborhood streets

Source: PBOT.

Figure 12. Example of road configuration in Portland after street redesign from 

five lanes to three lanes.

• A 13 percent reduction in vehicular turning speeds due to left turn calming

• A 71 percent reduction in speeding over the speed limit due to automated enforcement

• A 94 percent reduction in top end speeding due to automated enforcement

The Safe System Approach Highlights

• Death/serious injury is unacceptable: The City adopted Vision Zero in 2015.

• Humans make mistakes/humans are vulnerable: Vision Zero efforts prioritize vehicular 

speed reduction in Portland.

• Redundancy is crucial: The city’s multidisciplinary approach to reducing speeds includes 

engineering, enforcement, and education efforts.
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

Background

The City of Portland is the county seat of Multnomah County and is the largest city in the State of 

Oregon, with a population of approximately 653,000. Portland committed to Vision Zero in 2015 

and released an action planin 2016.1The Portland Bureau of Transportation (PBOT) has applied 

Safe System principles to update speed limits on nearly all streets citywide since 2017, as allowed 

by State law, and reduced the residential street speed limit from 25 mph to 20 mph in 2018. More 

than 90 percent of non-freeway streets in Portland have speed limits no higher than 30 mph, in 

accordance with the World Health Organization’s best practices for urban areas. PBOT continues 

to update and evaluate the impact of speed limit reduction and pursues complementary speed 

management practices, including signal retiming, road restriping that accommodates buffered bike 

lanes, and traffic calming to reinforce posted speeds.

Implementation

As part of its Vision Zero efforts, the City of Portland adopted a multi-disciplinary approach for 

speed reduction citywide. The main strategies to lower speeds and reduce the chance of death or 

serious injury are summarized below:

• Residential speed limit reduction:2 The City reduced speed limits from 25 mph to 20 mph on 

most residential streets in 2018. Approximately 76 percent of non-freeways in Portland have a 

20 mph posted speed limit.

• Setting target speeds:3

 In 2016, PBOT submitted a request to ODOT to use an alternative 

methodology4 for speed zones on non-arterial roads with posted speed limits greater than 

25 mph. The City’s proposed methodology for setting speed limits incorporates the needs of all 

road users by focusing on the safety of VRUs. PBOT worked with ODOT to create a process 

in which PBOT submits a formal request to ODOT to lower the speed limit for each roadway 

section in question. The investigation method includes information on the street context, 

including land use, facilities for pedestrians and bicyclists, crash history, and recommended 

speed limits based on the Simplified Decision Matrix (Figure 13). In 2020, ODOT adopted 

revised statewide speed limit setting rules for urban areas to incorporate the alternative 

method’s more balanced consideration of safety for all users and reduced reliance on vehicular 

speed distribution data.

1

 City of Portland (2016). Vision Zero Action Plan: Saving Lives with Safe Streets. Retrieved from https://www.

portland.gov/sites/default/files/2020-04/vision-zero-action-plan.pdf.

2

 City of Portland (2022). “Speed Limits.” Retrieved from https://www.portland.gov/transportation/vision-zero/

speed-limits.

3

 National Transportation Safety Board (2017). Reducing Speeding-Related Crashes Involving Passenger 

Vehicles. NTSB/SS-17/01. Retrieved from https://www.ntsb.gov/safety/safety-studies/Documents/SS1701.pdf.

4

 PBOT (2016). Request to Use an Alternative Methodology for Speed Zones. Retrieved from https://

bikeportland. org/wp-content/uploads/2016/08/PDX_AlternativeSpeedZone_packet-2.pdf.
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

Source: PBOT.

Figure 13. Simplified speed limit matrix for fatal crash reduction by mode.

• Street redesign: One example of street redesign to lower speeds is the NE 102nd Avenue 

safety project.5

 NE 102nd Avenue was a high speed, High Crash Network corridor where 

pedestrian safety was a concern.6 One of the primary goals of the safety project was to reduce 

vehicular speeds along the corridor. The project design included a road diet that reduced the 

roadway from five to three vehicular travel lanes, lowered the speed limit to 30 mph, and 

installed improvements for pedestrians and bicyclists.

• Intersection left turn calming: Approximately 20 percent of pedestrian crashes in Portland 

result from left turning drivers failing to yield to pedestrians in the crosswalk at signalized 

intersections.7 Portland piloted a left turn calming project8 in 2019 using a combination of 

rubber bumps, delineator posts, and thermoplastic striping at 42 signalized intersections.

• Automated speed enforcement: Oregon allows Portland to use speed safety cameras on its 

High Crash Network streets. The city’s eight fixed speed safety cameras were installed between 

2016 and 2018.

• Community outreach and education: Portland has a citywide Struck Speed Campaign9 to 

inform citizens of the risk of death and serious injuries due to high speeds.

5

 Portland Bureau of Transportation. (2020). NE 102nd Ave Safety Project Pilot Evaluation Report. Retrieved 

from https://www.portland.gov/sites/default/files/2020-06/102nd-evaluation-report-jan-2020_0.pdf.

6

 City of Portland. (2022). “High Crash Network Streets and Intersections.” Retrieved from https://www.

portland. gov/transportation/vision-zero/high-crash-network.

7

 City of Portland. (2022). “Left-Turn Calming.” Retrieved from https://www.portland.gov/transportation/visionzero/ left-turn-calming.

8

 Portland Bureau of Transportation. (2020). Evaluation Report: Left Turn Calming Pilot Project. Retrieved 

from https://www.portland.gov/sites/default/files/2020-07/left-turn-calming-evaluation-report.pdf.

9

 City of Portland. (2022). Struck Traffic Safety Campaign. Retrieved from https://www.portland.gov/

transportation/vision-zero/struck.
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

Outcomes

PBOT does not have available crash data after the implementation of speed reduction measures and, 

therefore, the outcomes are measured in terms of impacts on vehicular speeds.

• Residential speed limit reduction: A study conducted to determine the impact on vehicular 

speeds following the residential speed limit reduction from 25 mph to 20 mph found a 

34 percent reduction in the odds of observing speeds greater than 30 mph and a 50 percent 

reduction in the odds of observing speeds greater than 35 mph.10

• Setting target speeds: In 2021, a segment of West Burnside Street was the first street in 

Portland to get a new speed limit under the alternative methodology for setting speed limits. 

A before-after analysis of impacts on vehicular speeds and crashes is not available.

• Street redesign: The before-after evaluation of the NE 102nd Avenue corridor showed a 

reduction in vehicle speeds and no significant changes to travel times. Further, there were no 

significant changes to volumes or speeds on nearby neighborhood streets.

• Intersection left turn calming: An evaluation of the pilot left turn calming project showed 

reduction of overall vehicular turning speeds by approximately 13 percent.

• Automated speed enforcement: Since the speed safety cameras were installed, speeding over 

the speed limit has dropped 71 percent and top-end speeding (more than 10 mph over the speed 

limit) has dropped 94 percent.11

Additional Information

Moving forward, all new High Crash Network capital projects in Portland will include project 

components that help achieve safe speeds. Further, the City is expanding left-turn calming to 

locations where permissive turns present risks to pedestrians. An important item to note is that 

Portland considers equity in speed safety camera placement so that cameras are not concentrated 

in any one community, and it also has options to tier camera fines based on family income and 

ability to pay. For further information, contact Matthew Kelly, Vision Zero Specialist at the Portland 

Bureau of Transportation, at matthew.kelly@portlandoregon.gov.

10 Portland State University. (2020). Effect of Residential Street Speed Limit Reduction from 25 to 20 mph on 

Driving Speeds in Portland, Oregon. Retrieved from https://www.portland.gov/sites/default/files/2020/pbot-20-mphspeed-study-finalv5.pdf.

11 Portland Bureau of Transportation. (2020). Legislative Report – Outcome Evaluation: Fixed Photo Radar 

System City of Portland 2019-2020. Retrieved from https://www.oregonlegislature.gov/citizen_engagement/Reports/

Fixed%20Photo%20Radar%20System_Portland%202019-20_FINAL.pdf.
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

Case Study A.7. Seattle Systemic Speed Limit Reduction—Seattle, 

Washington, USA

Key Successes

The Seattle Department of Transportation (SDOT) implemented a systemic speed limit reduction 

program by modifying existing speed limit signs and by increasing speed limit sign density 

(Figure 14). Overall, the impacts of speed limit reductions on speed and safety in Seattle include 

the following:

• A 22 percent reduction in all crashes and an 18 percent reduction in injury crashes

• A 10 percent reduction in 50th percentile speeds and a 7 percent reduction in 

85th percentile speeds

• A 54 percent reduction in the number of vehicles traveling at 40 mph or faster

Source: City of Seattle (2020). 35th Avenue SW Road Safety Corridor Project.

Figure 14. New speed limit sign on Greenwood/Phinney Avenue North.

The Safe System Approach Highlights

• Death/serious injury is unacceptable: The city adopted a Vision Zero Plan in 2015 to 

eliminate deaths and serious injuries by 2030.

• Humans make mistakes/humans are vulnerable: Reduction of speeds lower the impact 

forces during a crash, which lowers the crash severity.

• Responsibility is shared: The speed limit reduction program involves the city and external 

agency partners.
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

• Safety is proactive: The implementation of the speed limit program is systemic, 

including all arterial streets in the city.

• Redundancy is crucial: Prior to the systemic reduction on speed limits, the city 

implemented engineering (street redesign, signal timing changes) and enforcement 

speed reduction measures.

Background

One of the key elements of the City of Seattle’s Vision Zero programis reducing vehicular travel 

speeds to lower the risk of a fatal or serious injury crash.1

 Prior to setting target speeds citywide, 

the city implemented pilot projects. The Safe System Approach in Seattle emphasizes engineering 

measures to support the lower speed limits. The chronological development of Seattle’s efforts to 

reduce vehicular speeds is summarized below:

• Street design: In 2015, the city redesigned several streets by converting them from four-lane 

to three-lane roads. Examples included Rainier Avenue South and 35thAvenue SW.2, 3Rainier 

Avenue South was one of the first corridors where the city piloted the USLIMITS2speed limit 

setting approach to set the speed limit to 25 mph.4

• Signal timing: In 2016, the city retimed the downtown traffic signals and set the speed limit 

to 25 mph.

• City Municipal Code: In 2016, Seattle went through the process of revising the Seattle 

Municipal Code to lower the default arterial and non-arterial speed limits to 25 mph and 

20 mph, respectively (from 30 mph and 25 mph).5

• Urban Villages: In 2018 and 2019, the city shifted its focus to urban villages, where 

80 percent of crashes involved pedestrians.6

 A 25 mph speed limit was established for streets 

within the urban villages, and a speed limit sign-spacing standard was developed. The 25 mph 

speed limit was based on operating speeds (to prioritize buses and people walking or biking; 

buses operate at 25 mph) and the USLIMITS2 (50th percentile speed). After completing efforts 

for several urban villages and collecting data, a justification for target speeds was formed.

• Speed limit policy: From 2020 to 2021, the city developed a new speed limit policy and 

placed speed limit signs on every arterial street. Approximately 90 percent of Seattle’s arterial 

network has a posted speed limit of 25 mph.

1

 City of Seattle. (2015). Vision Zero: Seattle’s Plan to end Traffic Deaths and Serious Injuries by 2030. 

Retrieved from http://www.seattle.gov/documents/Departments/beSuperSafe/VisionZeroPlan.pdf.

2

 City of Seattle (2022). “Rainier Improvements.” Retrieved from https://www.seattle.gov/visionzero/projects/

rainier-ave-s.

3

 City of Seattle. (2020). “35th Avenue SW Road Safety Corridor Project.” Retrieved from http://www.seattle.

gov/ visionzero/projects/35th-ave-sw.

4

 Federal Highway Administration. (2020). USLIMITS2: Tool to Aid Practitioners in Determining Appropriate 

Speed Limit Recommendations. Retrieved from https://safety.fhwa.dot.gov/uslimits/.

5

 City of Seattle. (2016). Seattle Municipal Code. Retrieved from https://library.municode.com/wa/seattle/codes/

municipal_code.

6

 City of Seattle (2022). Seattle Geo Data: Urban Centers, Villages, Manufacturing Industrial Centers. 

Retrieved from https://data-seattlecitygis.opendata.arcgis.com/datasets/urban-centers-villages-manufacturing-industrialcenters/explore?location=47.620656%2C-122.335550%2C12.00.
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

• Ongoing effort: The city’s speed limit reduction work is ongoing, and it continually evaluates 

all arterial streets and reduces speed limits where appropriate. This is a collaborative process 

that involves the city and external agency partners.

Implementation

As part of the city’s efforts to reduce vehicular speeds in Seattle, SDOT implemented a speed 

limit reduction by modified signage. SDOT did not market the speed limit reduction changes 

through a communications campaign, did not increase enforcement, or make any other engineering 

adjustments to the street design, geometry, or signal timing (any changes were made prior to the 

speed limit signage modifications). By removing these variables, SDOT was able to review the 

safety and speed impacts of two specific changes: speed limit signs with a new reduced speed and 

increased speed limit sign density.

Before speed limit reduction implementation efforts, locations had 30 mph signs with sign spacing 

ranging from 1 to 1.5 miles in each direction or they were unsigned (with a default 25 mph 

speed limit). After implementation, all locations included new 25 mph signs spaced at 0.25 mile 

intervals in each direction. A before-after studywas conducted at individual corridors and urban 

centers/villages in 2020 to evaluate the impact of reducing speed limits on speeds and safety, as 

summarized in Table 9.

7

7

 Seattle Department of Transportation. (2020). Speed Limit Case Studies. Retrieved from http:// www.seattle.

gov/documents/Departments/SDOT/VisionZero/SpeedLimit_CaseStudies_Report.pdf.
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

Table 9. Speed limit evaluation data collection in Seattle.

Street

Study 

Area Type

ADT 

(veh/ day)

Previous 

Speed Limit 

(mph)

Previous Speed 

Limit Sign 

Spacing (mi) Implementation

Greenwood/ 

Phinney Ave N

1.3 mi 

corridor

13,000 30 1 Replaced existing 30 

mph speed limit signs 

with 25 mph signs and 

installed new 25 mph 

signs at .25 mile spacing

NW/N 85th St 1.9 mi 

corridor

19,000 25 Unsigned Installed new 25 mph 

signs at .25 mile spacing

N/NE 45th St 2.2 mi 

corridor

22,500 25 Unsigned Installed new 25 mph 

signs at .25 mile spacing

Green Lake/ 

Roosevelt 

Urban Village

Urban 

Village

N/A 30 and 25 Segments 

with 30 mph 

speed: 1.5- mi; 

segments with 

25 mph speed 

limit: unsigned

Installed new 25 mph 

signs at .25 mile spacing

U-District 

Urban Center

Urban 

Village

N/A 30 and 25 Segments 

with 30 mph 

speed: 1.5- mi; 

segments with 

25 mph speed 

limit: unsigned

Installed new 25 mph 

signs at .25 mile spacing

Source: City of Seattle, Seattle Department of Transportation Speed Limit Case Studies. Retrieved from http://www.seattle.gov/documents/

Departments/SDOT/VisionZero/SpeedLimit_CaseStudies_Report.pdf.
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

Outcomes

For each study area included in the before-after analysis, speed limit reduction in Seattle resulted in 

the speed and safety outcomes shown in Table 10:

Table 10. Outcomes of speed limit reductions in Seattle.

Street All Crashes

Injury 

Crashes

50th 

Percentile 

Speed

85th 

Percentile 

Speed

Number of 

Vehicles 

Traveling at 

40 mph or 

Greater

Greenwood/ 

Phinney Ave N -35% -21% -7% -7% -64%

NW/N 85th St -39% -31% -3% -1% -45%

N/NE 45th St -14% -11% -25% -12% -66%

Green Lake/ 

Roosevelt Urban 

Village -24% -13% -2% -4% -47%

U-District Urban 

Center -18% -18% -15% -9% -66%

OVERALL -22% -18% -10% -7% -54%

Source: City of Seattle, Seattle Department of Transportation Speed Limit Case Studies. Retrieved from http://www.seattle.gov/documents/

Departments/SDOT/VisionZero/SpeedLimit_CaseStudies_Report.pdf.

Further, the city reported that target speeds set up the framework for all new projects to design to the 

new lower speed limit, influencing speeds before the projects go into construction.

Additional Information

The estimated cost to install speed limit signs in Seattle is $4,000 to $5,000 per mile and includes 

design, materials, and labor. For further information, contact James Le, SDOT Vision Zero/Proj- ect 

Development Division Senior Civil Engineer, at James.Le@seattle.gov.
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

Case Study A.8. Auckland Transport Safe Speeds—Auckland, New Zealand

The Safe System Approach Highlights

• Death/serious injury is unacceptable: New Zealand is committed to eliminating fatal and 

serious injury crashes. New Zealand’s Road to Zero National Road Safety Strategy 2020–2030 

focuses on Vision Zero. Auckland Transport (AT) adopted Vision Zero in 2019 with the goal of 

reaching zero deaths on their road network by 2050.

• Humans make mistakes/humans are vulnerable: Set appropriate speed limits that are safe 

for all road users.

• Responsibility is shared: International road safety experts, along with AT staff and partners, 

worked together to change Auckland’s safety culture. Public consultation was part of the 

process to change speed limits in Auckland.

Background

National Context

In 2016, the Waka Kotahi New Zealand (National) Transportation Agency published the New 

Zealand Speed Management Guide. This document set out a new framework for setting safe 

and appropriate speed limits. This was a significant shift in what speeds limits were considered 

appropriate for different roads and changed expectations around speed limit setting.

Regional Context

Auckland Transport is an Auckland Council Controlled Organization accountable for delivering 

an efficient, effective, and safe land transport system in Tāmaki Makaurau (Auckland), New Zealand’s largest city, with a population of approximately 1.6 million people.

From 2013 to 2017, Auckland experienced a 65 percent increase in road fatalities and serious 

injuries. In 2017 alone, the city saw 64 deaths and 749 serious injuries, a level of road trauma last 

seen in Auckland 20 years prior.

International road safety experts, along with AT staff, helped to encourage an important change in 

thinking about road safety within AT and their partners—shifting the approach from a traditional 

focus of “blaming individual road users” to instead “designing a more forgiving transport system 

where people who make common mistakes do not end up killed or seriously injured.” This helped 

to engrain the Safe System Approach and develop a desire for Vision Zero outcomes. It was also 

supported by the development of several guidelines and other documents aligned to a safe system 

and Vision Zero. One element of this approach is Auckland Transport’s Safe Speeds program.
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

Process

The Waka Kotahi New Zealand Speed Management Guide was mainly used to determine the safe 

and appropriate speed limit for different roads in the AT Safe Speeds program.

The Speed Management Guide expects that the speed limit aligns with the safe and appropriate 

speed (SaAS); however, it is not always necessary to change the speed limit to the SaAS. Instead, 

the road could be redesigned to increase the SaAS so that it supports the existing (or higher) speed 

limit. This is where additional infrastructure is provided so that when a crash occurs at the current 

operating speed, it is unlikely to result in a death or serious injury.

Evidence-based tools like Infrastructure Risk Rating (IRR)—a road assessment methodology 

designed to assess road safety risk based on the road and roadside environment—and safety 

science were used to determine the correct part of the network to focus on. IRR was important 

in determining the SaAS for a road segment because, unlike traditional road safety metrics, IRR 

doesn’t consider historical crashes. Instead, IRR is a proactive measure which is used to provide 

an approximation of underlying levels of risk for a road segment even when no crashes have 

been observed. This was especially useful for lower volume parts of the network. IRR can also be 

considered a basic version of the International Road Assessment Programme (iRAP) tool, requiring 

fewer input attributes which could be generated from the following existing national datasets:

• Road stereotype

• Alignment

• Carriageway width

• Roadside hazards

• Land use

• Intersection density

• Access density

• Traffic volume

For speed management in New Zealand, the IRR assessment was undertaken at a national level, 

giving councils like Auckland the evidence base to target their highest risk routes. The national IRR 

and SaAS assessments were then made available to all New Zealand local councils through the 

Safer Journeys Risk Assessment Tool website, also referred to as “MegaMaps.”

By combining the Speed Management Guide and MegaMaps metrics with AT’s knowledge of 

the local network, AT was able to review current speed limits and determine safe and appropriate 

speed limits for the roads. These where then prioritized in the first tranche (phase). The next 

step was the bylaw consultation process which allowed Aucklanders to submit feedback on the 

recommended changes.
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

Implementation

Following reviewing and consulting with the public, a list of possible options was provided to the 

AT Board which can be viewed via the following link: https://at.govt.nz/media/1981112/item131-attachment-6-open-22-october-2019-safe-speeds-implementation-options-report.pdf.

Although small changes were made from the original scope, Table 11 shows a high percentage of 

the benefits of the selected option, with a total estimated deaths and serious injury (DSI) reduction 

of 86.6 over a 5-year period.

Table 11. Option 3 estimated costs and benefit table.

Short List/ 

Option

Estimated 

DSI Saving 

in five years

Benefits 

Realization (%) Estimated Cost

Rural Roads 

(Option 3G) 51.3 100.0% $0.5 million

City Centre 

(Option 4E) 24.1 96.8% $2.8 million plus approximately $5–$10 

million supporting enhanced safety measures

Urban Roads 

(Option 2A) 7.2 100.0% $0.2 million

Residential 

(Option 2A) 1.5 100.0% $5.4 million

Town Centres 

(Option 4A) 2.5 100.0% $8.2 million

TOTAL 86.6 99.1% $22–$27 million

Source: Auckland Transport, 2019.

The Speed Limit Bylaw

In October 2019, the AT Board approved the Speed Limits Bylaw (2019). This bylaw reduced 

the speed limit on over 800 km (497 miles) of Auckland roads. Customer surveys, as well as a 

Monitoring and Evaluation Plan, were set up to monitor the effectiveness of the bylaw.

References and Additional Information

Sources/Web pages for reference: 

Contact us (Auckland, NZ).

Safe Speed Programme 2019: Implementation Options Report.

Speed limit changes around Auckland Public Feedback Report.
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

Case Study A.9. Network-Wide Speed Limit Reduction—Mornington 

Peninsula, Australia

Key Successes

The speed limit reductions in Mornington Peninsula, Australia resulted in the following safety 

outcomes:

• An average 3 mph mean operating speed reduction after 2 years of the speed limit being 

reduced from 68 mph to 50 mph.

• An even greater mean speed reduction of 4 mph on these roads after 2 years for a subset of 

roads that carry more than an average of 1,000 vehicles per day.

• An average 2.5 mph mean operating speed reduction by reducing the speed limit from 56 mph 

to 50 mph.

• Number of drivers traveling below the target speed of 50 mph increased significantly for both 

speed changes. In both cases, over 60 percent of drivers were under the target speed of 50 mph 

in the after period, compared with 42 percent and 46 percent, respectively, in the before period.

• An estimated 20 percent reduction in fatal and serious injury crashes on all roads.

The Safe System Approach Highlights

• Death/serious injury is unacceptable: Mornington Peninsula’s efforts to lower speed limits 

has a goal of eliminating fatal and serious injury crashes.

• Humans make mistakes/humans are vulnerable: Reduction of speed limit to reduce crash 

impact forces.

Background

Mornington Peninsula Shire is located southeast of Melbourne, Victoria, Australia and has an 

estimated population of 168,000. Mornington Peninsula Shire Council (MPSC) has demonstrated 

strong leadership in adopting and applying the Safe System approach to improve road safety in the 

Mornington Peninsula. Mornington Peninsula offers a unique environment in which to undertake 

and evaluate this speed trial. Visitors to the region, who make a significant contribution to the 

economy, often don’t know their destination, stopping at places of interest on winding roads. 

These roads are unlikely to receive infrastructure treatments in the foreseeable future, and so the 

introduction of safer speed limits is the most suitable treatment to reduce risks on these roads for 

both visitors and the local community.

In 2019, Mornington Peninsula experienced significant road trauma, observing the most deaths of 

any local government area in Victoria. From January 2019 to November 2019, 100 people were 

seriously injured and 14 were killed on MPSC roads.
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

Implementation

To address the concerns regarding road deaths and serious injuries and to reduce safety risk in the 

long term in Mornington Peninsula, MPSC acted quickly in applying a network wide speed limit 

reduction trial. Speed limits were reduced from 56 mph or 62 mph to a new speed limit of 50 mph 

on 33 high-speed local roads (Figure 15) beginning in early 2020.

Source: Mornington Peninsula Shire.

Figure 15. Mornington Peninsula Safer Speeds Trial.

Outcomes

Program evaluations are an important part of the Victoria Department of Transport (Victoria DOT) 

Safer Roads program because they provide an understanding of the effectiveness of infrastructure 

improvements. This informs decisions regarding future treatments. Additionally, it allows for 

analysis and feedback on treatments that preformed inadequately. It is important that the results of 

evaluations are statistically robust, so that investment decisions are based on creditable information.

The Victoria DOT’s “Safer Speeds on High Speed Local Government Area (LGA) Roads” 

evaluation framework was applied to evaluate the effectiveness of the two MPSC speed limit trials:

• Trial 1 covered speed limit reductions from 62 mph to 50 mph on 20 routes. This is shown as 

the red lines in Figure 15.
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

• Trial 2 covered speed limit reductions from 56 mph to 50 mph on 15 routes. This is shown as 

the yellow lines in Figure 15.

For the speed limit reduction trial, before data were collected in December 2019. Three periods of 

after speed data have also been collected for the evaluation, including:

• May 2020 (After 1 Period)

• November 2020 (After 2 Period); and

• November/December 2021 (After 3 Period).

Following data collection, the objective of this evaluation was to assess the following observed and 

expected outcomes from the trial:

• Reduction in free flow mean speeds associated with a:

◦ Speed limit change from 62 mph to 50 mph (Trial 1)

◦ Speed limit change from 56 mph to 50 mph (Trial 2)

• Changes in speed limit compliance associated with the speed limit changes

• Changes in the proportion of motorists traveling below 50 mph (target of “below 50 mph” 

proportion) and below 62 mph (target “upper bound” proportion)

• Estimated fatal and serious injury (FSI) crash reductions expected from the speed limit change

The evaluation found:

• There was very strong evidence that an average 3 mph mean operating speed reduction is 

achieved after 2 years of the speed limit being reduced from 62 mph to 50 mph, a 12 mph drop.

• An even greater mean speed reduction of 4 mph was observed after 2 years for a subset of 

roads that carry more than an average of 1,000 vehicles per day.

• Across all after periods, a higher speed reduction was observed on a subset of roads that have 

higher operating speeds in the before case, and therefore a higher risk of FSI crashes.

• The 56 mph to 50 mph speed limit reductions showed some evidence of a 2.5 mph reduction in 

mean speeds.

• The number of drivers traveling below the target speed of 50 mph increased significantly for 

both the 62 mph to 50 mph and 56 mph to 50 mph speed changes. In both cases, more than 

60 percent of drivers were under the target speed of 50 mph in the after period compared with 

46 percent and 42 percent, respectively, in the before period. This is an important outcome 

from a Safe System perspective, as more drivers below these target speeds will significantly 

reduce the risk of FSI crashes.

• The trial also estimated an average reduction in FSI crashes of approximately 20 percent for 

the 62 mph to 56 mph roads. Some routes showed reductions as high as 34 percent.

• For the 56 mph to 50 mph routes, the reductions are likely to be less, with an average FSI 

reduction of 12 percent across the treated routes.
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

Case Study A.10. Speed Limit Reduction on Urban Roads—Republic of 

Korea

Key Successes

The speed limit reductions on urban roads in Korea resulted in the following safety outcomes:

• A 1.1 percent reduction in total crashes

• A 19.3 percent reduction in fatalities

• A 9.2 percent reduction in injuries

• A 4.8 percent equivalent property damage only (EPDO) reduction

• An 18.4 percent reduction in fatalities per 100 crashes

The Safe System Approach Highlights

• Death/serious injury is unacceptable: Reducing road fatalities is the main goal of speed limit 

reductions in Korea

• Humans make mistakes/humans are vulnerable: Speed limit reductions focused on 

pedestrian safety

Background

Information in this case study is summarized from a joint research project conducted by the Korea 

Transport Institute (KOTI) and the World Bank (Mitra, Job, Han, and Eom 2021).

In April 2016, the National Police Agency in Korea established the Transportation Infrastructure 

Construction Basic Plan. For the first time, the Safe Speed 5030 policy was adopted to improve 

urban pedestrian safety. Following this, the 5030 Council was formed; this included the Ministry of 

Land, Infrastructure, and Transport as well as several other relevant agencies. In the same year, the 

8th National Road Safety Basic Plan was presented.

Implementation

Three years after presentation of the 8th National Road Safety Basic Plan, the Approved Code of 

Practice of the Road Traffic Act was amended. This set the maximum urban speed limit at 31 mph. 

However, the country’s National Policy Agency has gone further, changing the speed limit of many 

urban roads to 19 mph.

To assess the safety benefits of lower speed limits on urban roads and to inform future policy 

development on speed limits in urban areas, the Korea Transport Institute (KOTI) and the World 

Bank conducted a joint research project. Specifically, this study analyzed how changes in the speed 

limit affected safety performance and operational performance. Table 12 shows the extent of the 

speed limit reductions that were implemented across cities in Korea.
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

Table 12. Korea case study – current status of lowering speeds across Korea.

Local government

Number of 

reduction 

sections

Official data 

release date Other

Seoul City 2,534 08/31/2016

Speed limit reductions tend 

to be 19 mph reduction 

sections due to designation as 

protection zones

Daegu City 865 09/2017 -

Daejeon City 168 08/22/2016 -

Chungcheongbuk-do Province 253 08/30/2011 -

Jeollanam-do Province 754 09/19/2016 -

Gyeongsangbuk-do Province 313 08/31/2016 -

Jeju-do Province 162 04/2019 -

- = No data.

Source: Mitra, S., Job, S., Han, S., Eom, K. (2021). Do Speed Limits Reductions Help Road Safety? Lessons from the Republic of Korea’s 

Recent Move to Lower Speed Limit on Urban Road. Washington, DC: World Bank. http://hdl.handle.net/10986/36109.

Outcomes

After speed limit reduction in Korea, the joint research project conducted by KOTI and the World 

Bank evaluated the following:

1 The effectiveness of the reduced speed limits in terms of crash reduction through a 

before- after study.

2 If speed limit change had different effects across different crash types, user types, and crash 

severities.

3 The impact of speed limit change on transit speed through a before-after assessment.

To evaluate the effectiveness of speed limit reductions, the study team used an observational beforeafter study with a control group. The team obtained counts of crashes before and after in both the 

treatment site and comparison groups. Several different comparison analyses were con- ducted 

to check the impact of speed limit reductions. The following crash types were evaluated in the 

analysis:

1 Total crashes

2 Vehicle-to-vehicle crashes

3 Pedestrian crashes
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

Table 13 shows the overall results of the analysis. The results showed good alignment in moving 

towards the Safe System principles of accepting that crashes are inevitable, but they shouldn’t 

result in death or serious injury. This is shown by the relatively insignificant decrease in total 

crashes but a significant decrease in the number of people being injured or killed. Fatalities on 

roads where speed limits were changed were reduced by 19.3 percent compared to a 6.8 percent 

decrease in the control group.

Table 13. Korea case study – results of speed limit changes.

Crashes Fatalities Injuries

Equivalent 

Property 

Damage 

Only Crashes 

(EPDO)

Fatalities per 

100 Crashes

Before change in 

speed limit 8,891 114 3,142 19,869 1.28

After change in 

speed limit 8,794 92 2,852 18,906 1.05

Percent reduction 1.1% 19.3% 9.2% 4.8% 18.4%

Sections with 

unchanged speed 

limit, percent 

reduction

-3.0% 6.8% 11.8% 3.0% 9.6%

Note: A negative (-) sign before the percent change indicates an increase.

Source: Mitra, S., Job, S., Han, S., Eom, K. (2021). Do Speed Limits Reductions Help Road Safety? Lessons from the Republic of Korea’s 

Recent Move to Lower Speed Limit on Urban Road. Washington, DC: World Bank. http://hdl.handle.net/10986/36109.
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SAFE SYSTEM APPROACH FOR SPEED MANAGEMENT

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