Experience with automated red light enforcment in California.
Oxnard, California, United States
Reductions in Injury Crashes Associated with Red Light Camera Enforcement in Oxnard, California
Summary Information
This study evaluated the safety impacts of red-light camera enforcement in Oxnard, California. Cameras were installed at 11 of 125 signalized intersections throughout the city. Crash data for signalized and non-signalized intersections were obtained from the California Statewide Integrated Traffic Records System (SWITRS). The data represented crash statistics for Oxnard and three neighboring cities 29 months before, and 29 months after implementation in Oxnard. Three neighboring cities were used for baseline and control data since they were a reasonable distance away from Oxnard, and had similar weather conditions.
During the first month of operations (June 1997) violators were photographed in Oxnard, but no citations were issued. As required by law, signs were posted at major entrances to the city to inform motorists of red-light camera enforcement, however, issuance of citations did not begin until July 1, 1997. Penalties included a $271 fine and 1 point on the operator's driving record.
A linear regression model was used to determine the trends in total crashes, average crashes, and specific crash types in each city before and after red-light camera enforcement was initiated. An analysis of variance test was used to determine the statistical significance of changes in the number of crashes in Oxnard by considering changes in the crash rate in the control cities.
The results estimated that red light camera enforcement reduced the number of crashes at signalized intersections throughout Oxnard. Crashes at these intersections were reduced by 7 percent, right angle accidents were reduced by 32 percent, injury crashes were reduced by 29 percent, and right angle injury accidents were reduced by 68 percent.
The author vetted the results by examining the possibility that traffic volumes in Oxnard may have shifted from signalized to non-signalized intersections. Based on observations and traffic volume measurements at 12 intersections before and after implementation, the author concluded that a shift in citywide driving patterns was improbable during the study period.
