To brake or to accelerate? Safety effects of combined speed and red light cameras

IntroductionThe present study evaluates the traffic safety effect of combined speed and red light cameras at 253 signalized intersections in Flanders, Belgium that were installed between 2002 and 2007.MethodThe adopted approach is a before-and-after study with control for the trend.ResultsThe analyses showed a non-significant increase of 5% in the number of injury crashes. An almost significant decrease of 14% was found for the more severe crashes. The number of rear-end crashes turned out to have increased significantly (+ 44%), whereas a non-significant decrease (− 6%) was found in the number of side crashes. The decrease for the severe crashes was mainly attributable to the effect on side crashes, for which a significant decrease of 24% was found.Practical ApplicationsIt is concluded that combined speed and red light cameras have a favorable effect on traffic safety, in particular on severe crashes. However, future research should examine the circumstances of rear-end crashes and how this increase can be managed.