Experience using speed cameras to promote safety in the District of Columbia.
Washington DC, District of Columbia, United States
Speed Limit and Safety Nexus Studies for Automated Speed Enforcement for the District of Columbia
Summary Information
This study evaluated the connection between automated enforcement and safety at existing and planned automated speed enforcement locations in the District of Columbia. Field assessments were to account for roadway geometry, land use, and other exogenous factors, and independent researchers were consulted to analyze impacts on then traffic speeds, volume, and crash data before and after speed cameras were installed.
Accident Reports | Traffic Data | Speed Data | Location of Speed Cameras |
---|---|---|---|
Crash data for all speed camera locations Before and after crash data for existing speed camera locations 2009-2011 Traffic Safety Statistics Report 2011 Highway Safety Improvement Program Report (HSIP) 2012 Highway Safety Improvement Program Report (HSIP) 2014 Highway Safety Performance Plan DDOT Strategic Highway Safety Plan (SHSP) 2010, 2011, 2012 Top 5 Percent High Accident Locations Map | 2010 Traffic Volume Map 2011 Traffic Volume Map 2012 Traffic Volume Map | 2010 DC Speed Study 2006 DC Speed Study 2006 DC Speed Study Map Speed Camera Data | Installation Date for Existing Speed Camera Locations Signal Timing Data List of Signalized Intersections Signal Optimization Report |
Researchers analyzed historical data and collected traffic data to assess performance and quantify safety benefits after cameras were installed. Automatic traffic data recorders (ATRs) were used to collect data on vehicle speeds and traffic volumes, and the data collected were compared to the posted speed limits to determine if speeding decreased or continued to be problem at each site.
The safety assessment included an analysis safety records collected before and after the deployment. Researchers reviewed crash types, crash frequency, and crash severity data, and considered additional factors such as the day and time of crash, weather conditions, surface conditions, and lighting to identify any trends.
FINDINGS
- The total number of crashes at locations selected for automated enforcement decreased from 2,240 prior to installation of speed cameras to 1,863 after the installation (17 percent decrease).
- The total number of injury crashes at these locations decreased from 841 prior to installation to 673 after installation (20 percent decrease).
- The total number of injuries at these locations decreased from 1,251 prior to installation to 996 after installation (20 percent decrease).