title: Red light cameras: do they change driver behavior and reduce accidents?
abstract: BACKGROUND
  : Installation of red light cameras (RLC) at intersections associated with a high number of traffic accidents are currently in use to reduce the number of traffic collisions. The primary objective of this study was to evaluate the sustained effect of RLC on driver behavior. The secondary objective was to evaluate the number of collisions before and after RLC implementation.
  
  
  METHODS
  : For the primary objective, an 8-month prospective observational study after installation of RLC in September 2007 was undertaken at the intersection with the highest incidence of traffic accidents in the State of Louisiana. For the secondary objective, collision occurrences were collected 10 months before and after RLC installation. The mean number of citations was calculated by month, and the statistical significance of trend was obtained from a linear regression model across the study period and by t test to compare before and after citations were issued. The number of traffic collisions was compared using chi.
  
  
  RESULTS
  : During the initial 30 days, 2,428 violations per week were recorded, whereas in the subsequent 30 days, there were 534 citations per week issued (p < 0.001). After eight months, the number of citations was reduced to an average of 356 citations per week (p < 0.01). Mean number of citations decreased significantly during implementation of RLC. Three drivers received more than one citation. Although there was a trend in reduction of collisions from 122 to 97 before and after RLC, this did not reach statistical significance; p = 0.18.
  
  
  CONCLUSIONS
  : A significant and sustained reduction in the number of citations occurred as driving behavior was modified. Despite reducing the number of cars entering this intersection during a red light, RLC do not seem to prevent traffic collisions at this monitored intersection. Alternative means of injury prevention must be investigated.
authors.affiliation: Tulane University School of Medicine, New Orleans, Louisiana, USA.
authors.forename: Georgia M
authors.initials: GM
authors.lastname: Wahl
authors.forename: Tareq
authors.initials: T
authors.lastname: Islam
authors.forename: Bridget
authors.initials: B
authors.lastname: Gardner
authors.forename: Alan B
authors.initials: AB
authors.lastname: Marr
authors.forename: John P
authors.initials: JP
authors.lastname: Hunt
authors.forename: Norman E
authors.initials: NE
authors.lastname: McSwain
authors.forename: Chistopher C
authors.initials: CC
authors.lastname: Baker
authors.forename: Juan
authors.initials: J
authors.lastname: Duchesne
mesh_terms: D000056:Accident Prevention / Q000295:instrumentation*; D000063:Accidents, Traffic / Q000517:prevention & control* / Q000706:statistics & numerical data*; D001334:Automobile Driving / Q000523:psychology*; D006801:Humans; D035846:Law Enforcement; D008137:Longitudinal Studies; D010781:Photography; D012189:Retrospective Studies