Automated enforcement at intersections in the United States reduced traffic signal violations by 20 to 87 percent.
Experience with automated enforcement systems in the United States.
Made Public Date


Howard County
United States

Automated Enforcement of Traffic Signals: A Literature Review

Summary Information

This report documented the findings of a literature review carried out in the summer of 2001. The report discussed automated enforcement and the impacts of program operations in the United States. Automatic photo or video imaging was used to capture images of vehicles entering intersections after signals turned red. Fines were assessed in the range of $50 to $271.

Cameras used in these systems cost about $50,000 to $60,000 each (including installation) with additional $25,000 required for detectors, equipment cabinet, and mounting pole installations. The cost to operate and maintain a camera is about $5,000 per month. In the U.S., a private sector contractor that receives a portion of the fine revenue collected from the systems typically undertakes installation and a significant portion of a program’s operation.


An early Australian study indicated significant reductions in crashes due to implementation of camera enforcement, while a later study found that over time there were no significant changes in crash behavior due to the systems (though the small number of crashes experienced at the studied sites clouded the results). Studies of the systems in use in Glasgow, Scotland found both a significant crash reduction and that the most significant impact on violation behavior was a decrease in vehicles entering the intersection between 0.5 and 5 seconds into the red phase. A study of citywide crashes over the same time period found that red light cameras were likely one of several factors contributing to the overall decline in accidents. A graduate student study of two intersections with automated enforcement in Howard County, Maryland indicated a positive impact of the systems on right-angle crashes.
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