Do red lights reduce accidents?

Last week, the Insurance Institute for Highway Safety published findings that red-light-running violations had declined at intersections with the cameras in Arlington, Va, reports a story in today’s Wall Street Journal.

The study is consistent with other studiesshowing that the cameras make intersections safer, said Anne T. McCartt, co-author of the report and senior vice president for research at IIHS, which is funded by the insurance industry.

“But other researchers question the use of violations as a measure of safety. ‘As soon as you hear them talk about violation rates, these people are trying to obfuscate the fact that accidents don’t go down,’ said Declan O’Scanlon, a New Jersey state assemblyman and an opponent of the cameras.imgres-1

“’It is meaningless to study violations,’ Barbara Langland Orban, an associate professor of health policy and management at the University of South Florida, wrote in an email. ‘Safety is measured in crashes, in particular injury crashes, and violations are not a proxy for injuries. Also, violations can be whatever number an agency chooses to report, which is called an ‘endogenous variable’ in research and not considered meaningful as the number can be manipulated. In contrast, injuries reflect the number of people who seek medical care, which cannot be manipulated by the reporting methods of jurisdictions.’

“McCartt responded that the study is just the first step in planned research into the effect of Virginia cameras, which recently have been re-instituted after an earlier law authorizing their use expired. ‘It’s part of bigger research we’re going to do, looking at Virginia,’ McCartt said. ‘It’s going to allow us to do very strong research design.’

“The IIHS is one of the major producers of research in the field, which generally has found that the cameras are effective. Some camera critics question the IIHS’s motives, since its members can charge some motorists if they have been ticketed for running a red light. ‘It is financially to their benefit to have more camera tickets issued,’ said James C. Walker, a board member of the National Motorists Association, a 10,000-member drivers organization in Waunakee, Wis., that opposes the cameras. ‘To me, they’re just not unbiased.’”

 

For more, see: http://blogs.wsj.com/numbersguy/seeing-red-1208/?mod=WSJBlog

 

 

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