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

Abstract

Introduction: The 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.

Method: The adopted approach is a before-and-after study with control for the trend.

Results: The 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 applications: It 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.

Keywords: Before-and-after study; Effectiveness; Rear-end crash; Side crash; Speed and red light camera.