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CWRU study: Red-light cameras don't reduce accidents or make intersections safer

Posted at 2:25 PM, Jul 30, 2018

While red-light cameras reduce the number of motorists who run red lights, they do not reduce the number of traffic accidents or injuries at the intersections where they are installed, according to a new study from Case Western Reserve University in Cleveland.

The study found that at intersections with red-light cameras, drivers tended to brake harder and more abruptly, increasing fender-benders and so-called “non-angle” collisions.

“Once drivers knew about the cameras, they appeared to accept a higher accident risk from slamming on their brakes at yellow lights to avoid an expensive traffic citation—thereby decreasing safety for themselves and other drivers,” said Justin Gallagher, an assistant professor of economics at Weatherhead School of Management at Case Western Reserve.

Fewer drivers go through the red light, but "because all these vehicles are stopping, many suddenly or unexpectedly, there's many more fender benders, rear ends, sideswipes, single-car accidents," Gallagher told News 5. "If anything, they make the roads more dangerous."

The study analyzed data on collision over a 12-year span reported by the Texas Department of Transportation, focusing on data while red-light cameras were in use, then removed, in Houston. The study also drew on similar data from Dallas, where red-light cameras are still in use.

The data was gathered in Texas because it includes precise numbers from across the state over a period of time where the cameras were operating and then when they were removed.

In Houston, the installation of cameras led to an 18 percent increase in non-angle accidents, the researchers said. There was a total estimated 28 percent increase in non-angle collisions in the combined sample areas of Houston and Dallas.

"On net, it turns out there are more accidents when the cameras are there than when the cameras are not there," Gallagher told News 5.

The study did show that after the cameras were removed in Houston, there were 26 percent more “angle” accidents, such as T-bone collisions, which are considered the most dangerous. However, researchers concluded that it is likely that the cameras led to more accidents overall, as there were more non-angle accidents.

“There is no reason to believe that there is a reduction in overall accidents thanks to red-light cameras,” Gallagher said. “Our analysis does not support the case that the cameras improve public safety, which is one of the main justifications used by public officials and law enforcement.”

More than 400 communities in the United States, including 36 of the 50 largest cities, have installed red-light cameras, typically at busy intersections with a history of accidents. Some communities have since removed the cameras, including Cleveland.

Data on the types of injuries being incurred from traffic accidents at intersections with red-light cameras failed to provide a case that the cameras increased the safety of these intersections, according to Gallagher.

“There is clear evidence that installing a camera reduces the number of vehicles running a red light,” Gallagher said, “but the predicted relationship between the number of vehicles running red lights and the total number of accidents is ambiguous—and certainly not compelling enough to justify some claims of proponents of these devices.”

Locally, Newburgh Heights, Linndale, East Cleveland, Parma and Akron operate traffic enforcement cameras. Last year, News 5 reported that East Cleveland was violating state law by continuing to operate 14 cameras without an officer present.

When asked whether any city with red-light cameras may reconsider them as a result of this study, Gallagher responded: "I'd like to think so, but I guess we'll have to wait and see."