In June 2010, Arlington County, Virginia, installed red light cameras at four heavily traveled signalized intersections. The effects of the camera enforcement on red light violations were examined.Methods:
Traffic was videotaped during the 1-month warning period and 1 month and 1 year after ticketing began at 12 signalized intersections, including the four camera intersections, four “spillover” intersections without cameras in Arlington County (two on the same travel corridors as the camera intersections and two on different travel corridors), and four “control” intersections without cameras in adjacent Fairfax County. Rates of red light violations per 10,000 vehicles were computed. Logistic regression models were used to estimate changes in the likelihood of red light violations at the camera intersections and at the two sets of spillover intersections, relative to what would have been expected without the cameras, based on changes at the control intersections.Results:
At the camera intersections, there were significant reductions 1 year after the start of ticketing in the odds of red light violations occurring at least 0.5 second (39 percent) and at least 1.5 seconds (86 percent) after the light turned red, relative to what would have been expected without the cameras. There was a marginally significant 48 percent reduction in violations occurring at least 1 second into the red signal phase. At the non-camera intersections located on the same travel corridors as the camera intersections, there were declines in the odds of violations occurring at least 0.5 second (14 percent), 1 second (25 percent), and 1.5 seconds (63 percent) into the red signal phase; none of these changes was significant. The odds of violations increased at the non-camera intersections located on other travel corridors in Arlington County, compared with expected violations based on the control intersections.Conclusions:
Consistent with prior research, there were significant reductions in red light violations at camera-enforced intersections. These reductions were greater the more time had passed since the light turned red, when violations are more likely to result in crashes. Spillover benefits were observed only for nearby intersections on the same travel corridor, and these were not always statistically significant. At intersections on other travel corridors, red light running increased, compared with expected rates based on the control intersections. This evaluation examined the first year of Arlington County’s red light camera program, which was modest in scope and without ongoing publicity. A larger, more widely publicized program likely is needed to achieve community-wide effects.