title: Explaining Differences in Crash and Injury Crash Outcomes in Red Light Camera Studies.
abstract: Evaluations of red light camera (RLC) traffic safety programs have produced mixed results. Some conclude RLCs were associated with significant increases in motor vehicle crashes and injury crashes, whereas other research reports safety benefits. To understand the difference in findings, the present analysis assessed whether standards required for internal validity in quasi-experimental public health program evaluations were adhered to in frequently cited RLC analyses. Four evaluation standards were identified and used to assess the RLC analyses: lack of bias in the selection of both (a) treated sites and (b) comparison sites, (c) integration of relevant control variables in the analysis, and (d) full disclosure of results of the statistical analysis. Six leading RLC studies were then critiqued. Only two of the six studies adhered to the four standards and both concluded RLCs were associated with significant increases in crashes and injury or possible injury crashes. A third study reported an increase in fatal/injury crashes but did not test for statistical significance. Three studies reported equivocal findings; however, each failed to adhere to most standards. Differences in findings were attributed to the evaluation methods used. If implementing an RLC program, communities should use sound public health evaluation methods to assess effectiveness.
authors.affiliation: Department of Health Policy and Management, College of Public Health, University of South Florida, Tampa, FL, USA borban@health.usf.edu.
authors.forename: Barbara
authors.initials: B
authors.lastname: Langland-Orban
authors.affiliation: Department of Health Policy and Management, College of Public Health, University of South Florida, Tampa, FL, USA.
authors.forename: Etienne E
authors.initials: EE
authors.lastname: Pracht
authors.affiliation: Department of Health Policy and Management, College of Public Health, University of South Florida, Tampa, FL, USA.
authors.forename: John T
authors.initials: JT
authors.lastname: Large
authors.affiliation: Department of Biostatistics and Epidemiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.
authors.forename: Nanhua
authors.initials: N
authors.lastname: Zhang
authors.affiliation: Department of Surgery, University of Florida, Jacksonville, FL, USA.
authors.forename: Joseph T
authors.initials: JT
authors.lastname: Tepas
mesh_terms: D000063:Accidents, Traffic / Q000401:mortality / Q000706:statistics & numerical data*; D003627:Data Interpretation, Statistical; D006801:Humans; D015397:Program Evaluation; D012107:Research Design; D013997:Time Factors; D014947:Wounds and Injuries / Q000453:epidemiology* / Q000401:mortality
keywords: injury crashes; motor vehicle safety; program evaluation; quasi-experimental research design; red light camera