Study Details
Study Title: Red light for red-light cameras?: A meta-analysis of the effects of red-light cameras on crashes
Authors: Erke, A.
Publication Date:SEP, 2009
Abstract: A meta-analysis has been conducted on the effects of red-light cameras (RLCs) on intersection crashes. The size and direction of results reported from studies included in the meta-analysis are strongly affected by study methodology. The studies that have controlled for most confounding factors yield the least favourable results. Based on these studies, installation of RLCs leads to an overall increase in the number of crashes by about 15%. Rear-end collisions increase by about 40% and right angle collisions, which are the target crashes for RLC, are reduced by about 10%. All effects are, however, non-significant. Meta-regression analysis shows that results are more favourable when there is a lack of control for regression to the mean (RTM). An interaction is found between control for RTM and control for those spillover effects that result from the tendency of RLCs to affect crash levels in nearby intersections without RLC. In studies controlling for RTM, additional control for spillover effects reduces the favourability of results still further. Studies controlling for both RTM and spillover effects tend also to control for more additional factors than other studies. It is likely that the results are affected by additional moderator variables, which could not be investigated in this meta-analysis. RLCs may reduce crashes under some conditions, but on the whole RLCs do not seem to be a successful safety measure.
Study Citation: Erke, A. "Red light for red-light cameras?: A meta-analysis of the effects of red-light cameras on crashes", Accident Analysis and Prevention, Vol. 41, Issue 5 (2009), pp. 897-905
CMFs Associated With This Study
Category: Advanced technology and ITS
Countermeasure: Install red-light cameras
| CMF | CRF(%) | Quality | Crash Type | Crash Severity | Roadway Type | Area Type |
|---|---|---|---|---|---|---|
| 1.15 | -15 |  | All | All | Not Specified |
| 1.13 | -13 | | All | K,A,B,C | Not Specified |
| 1.43 | -43 | | Rear end | All | Not Specified |
| 0.1 | 90 | | Angle | All | Not Specified | Not specified |
