Pedestrian Safety Guide and Countermeasure Selection System


A speed-monitoring trailer. Source: Flickr - Wayan Vota (2009)




Speed-Monitoring Trailers

Speed-monitoring trailers—sign boards on trailers that display the speed of passing vehicles—are used by police departments and transportation agencies as educational tools that can enhance enforcement efforts directed at speed compliance. Speed radar trailers are best used in residential areas and may be used in conjunction with Neighborhood Speed Watch or other neighborhood safety education programs. Speed monitoring equipment may also be used in other types of areas where speeding is a problem, and/or where other roadway improvements have not been effective in keeping vehicle speeds at acceptable levels. Speed trailers help raise residents’ awareness of speed, but are not substitutes for permanent actions, such as traffic-calming treatments, to address neighborhood speeding issues.

Speed-monitoring trailers can be used at several locations and should have police monitoring and enforcement to maintain driver respect. Many cities will place speed trailers at the requests of residents.


Excessive automobile speeds increase the risk to pedestrians. Speed-monitoring trailers can enhance enforcement efforts through public education and awareness.


• Occasional enforcement is needed to supplement the speed-monitoring trailers.
• Speed-monitoring trailers are not a substitute for engineering measures.
• Trailers should not obstruct the pedestrian travelway or sightlines.

Estimated Cost

The cost for each unit is approximately $7,000 to $18,000. There may be an additional cost to move and monitor the trailer.

Safety Effects

A summary of studies that have looked at the safety effects of speed monitoring can be found here.

Case Studies

Las Vegas, Nevada
Phoenix, AZ
Village of Great Neck Plaza, New York
San Francisco, California
Phoenix, Arizona
Phoenix, Arizona