Effects of red light camera enforcement on red light violations in Arlington County, Virginia

In June 2010, Arlington County, Virginia, installed red light cameras at four heavily traveled signalized intersections. Effects of camera enforcement on red light violations were examined.

Traffic was videotaped during the 1-month warning period and 1month and 1year after ticketing began at the four camera intersections, four non-camera "spillover" intersections in Arlington County (two on travel corridors with camera intersections, two on different corridors), and four non-camera "control" intersections in adjacent Fairfax County. Logistic regression models estimated changes in the likelihood of violations at camera and spillover intersections, relative to expected likelihood without cameras, based on changes at control intersections.

At camera intersections, there were significant reductions 1year after ticketing in odds of violations occurring at least 0.5s (39%) and at least 1.5s (86%) after lights turned red, relative to expected odds without cameras, and a marginally significant 48% reduction in violations occurring at least 1s into red. At non-camera intersections on corridors with camera intersections, odds of violations occurring at least 0.5s (14%), 1s (25%), and 1.5s (63%) into the red phase declined compared with expected odds, but not significantly. Odds of violations increased at the non-camera intersections located on other Arlington County travel corridors.

Consistent with prior research, red light violations at camera-enforced intersections declined significantly. Reductions were greater the longer after the light turned red, when violations are more likely to cause crashes. Spillover benefits were observed only for nearby intersections on travel corridors with cameras and were not always significant.

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 is likely needed to achieve community-wide effects.