The impact of red light cameras on safety in Arizona

Shin, Kangwon and Washington, Simon (2007) The impact of red light cameras on safety in Arizona. Accident Analysis and Prevention, 39 6: 1212-1221. doi:10.1016/j.aap.2007.03.010


Author Shin, Kangwon
Washington, Simon
Title The impact of red light cameras on safety in Arizona
Journal name Accident Analysis and Prevention   Check publisher's open access policy
ISSN 0001-4575
1879-2057
Publication date 2007-03-01
Sub-type Article (original research)
DOI 10.1016/j.aap.2007.03.010
Open Access Status Not yet assessed
Volume 39
Issue 6
Start page 1212
End page 1221
Total pages 10
Place of publication Oxford, United Kingdom
Publisher Elsevier
Language eng
Formatted abstract
Red light cameras (RLCs) have been used in a number of US cities to yield a demonstrable reduction in red light violations; however, evaluating their impact on safety (crashes) has been relatively more difficult. Accurately estimating the safety impacts of RLCs is challenging for several reasons. First, many safety related factors are uncontrolled and/or confounded during the periods of observation. Second, “spillover” effects caused by drivers reacting to non-RLC equipped intersections and approaches can make the selection of comparison sites difficult. Third, sites selected for RLC installation may not be selected randomly, and as a result may suffer from the regression to the mean bias. Finally, crash severity and resulting costs need to be considered in order to fully understand the safety impacts of RLCs.

Recognizing these challenges, a study was conducted to estimate the safety impacts of RLCs on traffic crashes at signalized intersections in the cities of Phoenix and Scottsdale, Arizona. Twenty-four RLC equipped intersections in both cities are examined in detail and conclusions are drawn. Four different evaluation methodologies were employed to cope with the technical challenges described in this paper and to assess the sensitivity of results based on analytical assumptions. The evaluation results indicated that both Phoenix and Scottsdale are operating cost-effective installations of RLCs: however, the variability in RLC effectiveness within jurisdictions is larger in Phoenix. Consistent with findings in other regions, angle and left-turn crashes are reduced in general, while rear-end crashes tend to increase as a result of RLCs.
Keyword Red light running
Red light enforcement camera
Before-and-after study
Intersection safety
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collection: School of Civil Engineering Publications
 
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Created: Wed, 08 Mar 2017, 16:10:09 EST by Jeannette Watson on behalf of School of Civil Engineering