Vehicle speed plays a central, powerful role in the safety of pedestrian and bicyclists. Studies suggest that even a modest reduction in average vehicle speed can result in significantly fewer and less severe bicyclist and pedestrian crashes. A comprehensive study by the AAA Foundation concluded that an adult pedestrian struck by a motor vehicle traveling at 25mph has a roughly 10% chance of suffering a serious or fatal injury. Yet if a driver hits an adult pedestrian at 40mph, there is a 75% chance that the pedestrian would incur a severe or fatal injury. Moreover, as the Insurance Institute for Highway Safety (IIHS) has recently reported, the recent national rise in pedestrian fatalities is at least partially attributable to increased use of sport utility vehicles (SUV) and high horsepower vehicles.

Like most persistent traffic safety problems, speeding is a complex and situation-specific issue. In some communities across the United States, it is generally socially acceptable to speed in some areas (e.g., on cross-town arterials roads) and not in others (e.g., near schools). Not only that, drivers are often in a rush to reach their destinations. Given the complex nature of speeding, a comprehensive approach to managing speed is recommended for agencies and the communities they serve. Strategies include roadway design and adjacent land uses to naturally calm traffic, lower speed limits, high-visibility and automated speed enforcement operations, as well as roadway lighting improvements to create safer environments for bicycling and walking.

Resources

Speed Limit Setting Handbook
Federal Highway Administration (FHWA)
Provides practitioners with information on how to conduct an engineering study to set a speed limit for a speed zone based on the provisions in the Manual on Uniform Traffic Control Devices for Streets and Highways (MUTCD).

National Association of City Transportation Officials' (NACTO's) City Limits
National Association of City Transportation Officials (NACTO)
Outlines how to use a tested, context-sensitive safe systems approach to strategically set safer speed limits on urban streets to reduce traffic fatalities and injuries.

Institute of Transportation Engineers (ITE) Speed Management Resources
Institute of Transportation Engineers (ITE)
Presents a compendium of guides, policies, and practices related to managing traffic speeds.

State Laws for Slow Roads
League of American Bicyclists
Describes the Slow Roads Save Lives Campaign advocating for slower speeds and improved road design.

Safe System Approach for Speed Management
Institute of Transportation Engineers (ITE) and Federal Highway Administration (FHWA)
Introduces a five-stage framework to help practitioners better understand the impacts of speed on road safety.

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Examples

Speeding Prevention Campaigns
National Highway Traffic Safety Administration (NHTSA)
Details campaigns to combat speeding and its consequences.

Effects of Speed Limit Reduction in Boston
Insurance Institute of Highway Safety (IIHS)
Evaluates the effects of the speed limit reduction from 30mph to 25mph on speeds in Boston, Massachusetts.

Frequently Asked Questions on Speed in Seattle
Seattle Department of Transportation
Covers speed limit reduction and Vision Zero initiatives in the City of Seattle, Washington.

Drive 25: It's the Law! Campaign
New York City Department of Transportation
Encourages drivers to drive the posted 25mph speed limit in New York City.

Guidelines for Determining Speed Limits on Municipal Roadways
Minnesota Department of Transportation
Outlines a process for agencies to follow when deciding to make changes and offers alternative strategies.

More Examples >