Findings in red light study not conclusive
[Apparently a report was issued that red light cameras increase crash rates, read more why that report is flawed.] The public health community should tout our contributions to society, but only when conclusions are based on sound science. The University of South Florida report on red light cameras (The Nation’s Health, May 2008) doesn’t meet the test.
It’s not challenging to make news with counterintuitive conclusions contradicting established research. Reporting that safety belt laws increase highway deaths might grab headlines, but what if false results based on poor research methods were used to change policies?
The report from Florida isn’t new research. It’s an opinion piece based on several existing studies dismissed by experts in the highway safety field as having serious methodological flaws.
In one study from Greensboro, N.C., for example, researchers treated data from intersections with and without cameras as if the cameras had been randomly assigned to their locations. In fact, officials in Greensboro installed cameras at intersections with higher crash rates — more than twice as many crashes as other intersections in the city before the cameras were installed. The study ignored this difference and concluded that because crashes at intersections with cameras outnumbered those at the comparison sites, the cameras must be the culprits. Another tudy cited in the report also reached dubious conclusions because the methodology used wasn’t applied correctly.
Such pitfalls are avoided by relying on methodologically sound photo enforcement studies subjected to peer review. Unlike the research cited in the Florida report, these studies have been thoroughly critiqued by impartial experts to determine the validity of the methods and appropriateness of the conclusions.
Few public health problems take as great a toll as motor vehicle crashes. We need sound scientific evaluations to help guide policy-makers on effective countermeasures. It’s not just our opinion that red light cameras make intersections safer; the solid research shows that they do. The Florida report should be an embarrassment to public health researchers, not a point of pride.
Adrian K. Lund, PhD
Arlington, Virginia
President, Insurance Institute of Highway Safety
What's Related