U.S. cities that turned off their red light enforcement cameras experienced 30 percent more annual red-light running fatalities per capita than would have been expected had they been left on.

Experience of 14 large U.S. cities that shut down their red light enforcement programs between 2010 and 2014.

Date Posted
05/17/2017
Identifier
2017-B01141
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Effects of turning on and off red light cameras on fatal crashes in large U.S. cities

Summary Information

This study updates estimates of effects of activating red light cameras and offers a first look at effects of turning them off. Among 117 large U.S. cities with more than 200,000 residents in 2014, trends in citywide per capita rates of fatal red light running crashes and of all fatal crashes at signalized intersections were compared between 57 cities that initiated camera programs during 1992–2014 and 33 cities without cameras to examine effects of activating camera programs. Trends also were compared between 19 cities that removed cameras and 31 regionally matched cities with continuous camera programs to evaluate effects of terminating camera programs. Because several cities removed cameras during 2005–2008 and estimated effects might have been confounded by the subsequent economic downturn, primary analyses were limited to the 14 cities that removed cameras during 2010–2014 and 29 regionally matched cities with continuous camera programs.

METHODOLOGY

Study authors collected fatal crash data as well as population and unemployment data for large U.S cities, for cities both with and without red light camera enforcement. In the first analysis, 35 cities that had turned on the red light cameras between the years of 1992 and 2014 compared against a control group with similar land areas. Poisson regression models were used to rigorously examine the relationship of camera enforcement and other variables with fatal crashes. A similar method was used for determining the impacts of turning red light enforcement cameras off. The effects of ending red light camera enforcement and other predictors on the per capita rate of fatal red light running crashes were modeled by using the 14 cities that ended their camera programs during 2010–2014.

RESULTS

After controlling for temporal trends in annual fatal crash rates, population density, and unemployment rates, rates of fatal red light running crashes and of all fatal crashes at signalized intersections were 21 percent and 14 percent lower, respectively, in cities with cameras after cameras were turned on than would have been expected without cameras. In the 14 cities that terminated cameras between 2010–2014, rates of fatal red light running crashes and of all fatal crashes at signalized intersections were 30 percent and 16 percent higher, respectively, after cameras were terminated than would have been expected had cameras remained. This study adds to the body of evidence that red light cameras can reduce the most serious crashes at signalized intersections, and is the first to demonstrate that removing cameras increases fatal crashes.

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