title: Safety effects of fixed speed cameras - An empirical Bayes evaluation.
abstract: The safety effects of 223 fixed speed cameras that were installed between 2000 and 2010 in Norway were investigated in a before-after empirical Bayes study with control for regression to the mean (RTM). Effects of trend, volumes, and speed limit changes are controlled for as well. On road sections between 100m upstream and 1km downstream of the speed cameras a statistically significant reduction of the number of injury crashes by 22% was found. For killed and severely injured (KSI) and on longer road sections none of the results are statistically significant. However, speed cameras that were installed in 2004 or later were found to reduce injury crashes and the number of KSI on road sections from 100m upstream to both 1km and 3km downstream of the speed cameras. Larger effects were found for KSI than for injury crashes and the effects decrease with increasing distance from the speed cameras. At the camera sites (100m up- and down-stream) crash reductions are smaller and non-significant, but highly uncertain and possibly underestimated.
authors.affiliation: Institute of Transport Economics, Gaustadalleen 21, 0349 Oslo, Norway. Electronic address: alh@toi.no.
authors.forename: Alena
authors.initials: A
authors.lastname: Høye
mesh_terms: D000063:Accidents, Traffic / Q000517:prevention & control* / Q000706:statistics & numerical data*; D001499:Bayes Theorem; D006801:Humans; D009664:Norway; D010781:Photography / Q000295:instrumentation*; D012449:Safety
keywords: Crash; Empirical Bayes; Regression to the mean; Road safety; Speed camera