Cameras at Intersections Can Reduce Accidents
Study suggests these traffic monitors do change driver behavior
FRIDAY, April 22, 2005 (HealthDay News) -- Red-light traffic cameras may reduce crash-related injuries at busy intersections by as much as 30 percent, according to a review of international studies.
Red-light cameras have been in use in numerous countries since the 1970s, and more than 100 U.S. cities currently use the devices to monitor traffic. They've not been without their critics, however: Some groups charge that the cameras represent a further invasion of privacy on the part of government, or are installed to raise revenues in the form of fines.
At the same time, there have been few studies in the scientific literature on how red-light cameras affect traffic violations and crash injuries, noted review lead author Amy Aeron-Thomas, a researcher with the British group Roadpeace.
"Many of the included studies, even those several years old, came from Web sites and from reading related material, and not from the literature search of the transport and public health databases," Aeron-Thomas said in a prepared statement.
She and her colleagues analyzed 10 studies from the United States, Australia and Singapore, each of which compared traffic violations and crashes at signaled intersections before and at least a year after the installation of red-light cameras.
Many of those studies found a 10 to 20 percent reduction in crash-related injuries after installation of the red-light cameras, the researchers noted. However, most of the studies had some statistical flaws, including not taking into account what's referred to as the "spillover effect."
"As red-light camera programs involve publicity campaigns and warning signs, behavior in general may be influenced, with drivers inclined to obey red lights at all signalized junctions, thus reducing the risk of collisions at non-camera sites," Aeron-Thomas said.
One study that did account for the spillover effect was conducted in Oxnard, Calif. That study found a 30 percent reduction in crash-related injuries after red-light cameras had been in place for 20 months.
The findings appear in the April issue of the journal The Cochrane Library, published by The Cochrane Collaboration, an international organization that evaluates medical research.
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