In transportation safety, the term "countermeasure" is generally used to describe a safety program or approach to address a specific type of crash. This term may be used interchangeably with "treatment" or "intervention." While some agencies focus on infrastructure countermeasures (e.g., traffic calming, bike lanes) or behavioral countermeasures (e.g., enforcement, safety campaigns), it is ideal for agencies to take a comprehensive approach of multiple countermeasures to address more complex problems.

Countermeasure effectiveness is usually evaluated by a change in the number of crashes. When crash data are not available, researchers and practitioners may consider changes in road users' knowledge or behavior, such as speed or yielding rates, to determine countermeasure effectiveness, however, there is little research about how this type of evaluation correlates to safety. Before and after countermeasure studies to measure effectiveness are preferred since it can be challenging to infer safety results from cross-sectional studies. The effectiveness of any countermeasure can vary across geographies, as factors such as roadway design, public perception, law enforcement activities, lighting conditions, and more, are context specific. For a more advanced evaluation, with high quality data for multiple installations, researchers can calculate a Crash Modification Factor that estimates the safety effect.


FHWA Safe Transportation for Every Pedestrian (STEP) Studio provides resources, design guidance, research, and best practices for practitioners to identify appropriate countermeasures for improved pedestrian safety.

Advancing Pedestrian and Bicyclist Safety: A Primer for Highway Safety summarizes promising engineering treatments and behavioral programs and includes a glossary and case studies.

Advancing Pedestrian and Bicyclist Safety: A Primer for Highway Safety summarizes promising engineering treatments and behavioral programs and includes a glossary and case studies.

PEDBIKESAFE describes the process for selecting and implementing countermeasures and each includes an interactive selection tool and case studies.

Countermeasures that Work provides guidance for selecting effective, evidence-based countermeasures for traffic safety problem areas including bicycle and pedestrian safety.

Systemic Pedestrian Safety Analysis and Risk Based Prioritization provides a method to identify sites for potential safety improvements based on specific risk factors for pedestrians.

Crash Modification Factor (CMF) Clearinghouse provides a searchable database of CMFs, which can be used to compute the expected number of crashes after implementing an infrastructure countermeasure.

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City of Seattle Bicycle and Pedestrian Safety Analysis Project identifies locations to prioritize safety improvements with the goal of preventing future crashes.

Don't Cut Corners: Left Turn Pedestrian and Bicyclist Crash Study uses a data-driven approach to examine left turn pedestrian and bicyclist crashes in New York, New York.

Road Diet Case Studies summarizes case studies from nine different agencies and features projects that use a variety of pedestrian and bicycle safety countermeasures.

City Drivers Slow Down for Lower Speed Limit in Boston documents the effects of lowering the default speed limit on city streets by five miles per hour.

Publicly-Supported Road Diet Reduces Speeds in Alexandria, Virginia synthesizes a corridor project that improved safety for all road users, especially pedestrians.

Research Guides Countermeasure Selection in Boulder describes the city’s process for selecting treatments to improve safety at pedestrian crossings.

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