Red light cameras revisited. Recent evidence on red light camera safety effects.

The aim of this paper is to update the most recent published evidence on road safety estimates of recent red light camera (RLC) and speed/red light camera studies (SRLC). A literature search was carried out on RLC studies in the period 2013-2017 which, after screening, identified 18 recent studies on red light cameras (RLCs) and speed/red light cameras (SRLCs). The methodology and results of these studies were further examined and summary safety estimates were derived and compared to earlier meta-analysis summary estimates. The primary conclusion is that the new safety estimates from this paper show a 12% decrease of total crashes and confirm the general tendency of RLCs to reduce right angle crashes while at the same time increasing rear-end crashes. However, comparing the developments over time, the review reveals that safety estimates tend to increase with time (the safety effects of the most recent studies are the greatest). Also safety estimates suggest more positive effects with SRLCs than with RLCs. Most of recent studies indicate that spillover effects are present and can be quite substantial.