The traffic safety effect of combined speed and red light cameras

  • Published: Transport Research Arena 2014, Paris
  • Authors: E. De Pauw, S. Daniels, T. Brijs, E. Hermans, G.Wets
  • Date Added: 11 Feb 2016
  • Last Update: 11 Feb 2016
  • Format: pdf


To evaluate the traffic safety effect of combined speed and red light cameras (SRLCs).


Before and after study with control for the trend at 253 signalised intersections with SRLCs in Flanders, Belgium.

Key Findings:

  • The effect of the installation of speed and red light cameras (SRLCs) was analysed through a comparison of the crash numbers from after with before, taking into account different confounding variables. A comparison group was used, which controls for general trend effects. Other traffic safety measures that were implemented at the treated locations throughout the research period were taken into account. It was not, however, possible to control for the regression to the mean effect.

  • The installation of SRLCs generated a slight increase in the number of injury crashes. This can mainly be attributed to an increase in the number of rear end crashes (+44 per cent). The circumstances of this increase should be examined in future research.

  • The fatal and serious injury crashes showed a favourable effect (-14 per cent), that was largely the result of a decrease in the severe side crashes (-24 per cent).


Large scale analysis of SRLCs and the road safety effects, although all the sites were based in Belgium and regression to the mean was not accounted for.