Newswise — A new Australian review of existing research suggests that "speed cameras" and other devices can reduce automobile accident rates by allowing authorities to detect and cite speeders as they zip down the road.
"When speed cameras are in use, people slow down," said Russ Rader, spokesman for the Insurance Institute for Highway Safety in the United States. "It's Human Behavior 101."
But review authors led by Cecilia Wilson of the University of Queensland say that many of the studies they examined are "weak," and that more intensive research is needed to definitively confirm that the devices actually make drivers more careful.
Speed cameras are typically installed at intersections and equipped with speed sensors. A driver who exceeds the speed limit may be greeted with a citation in the mail and a photograph of his or her car.
The cameras are commonly found overseas in countries like the United Kingdom and Australia. But they're fairly rare in the United States.
According to Rader, as of late 2005 speed cameras were in place in several cities in Colorado, Arizona, Oregon and Ohio as well as San Jose, Calif., Charlotte, N.C., and Washington, D.C.
By contrast, Rader said that at least 100 American cities use red-light cameras, which catch people running through stoplights. "In this country, running red lights is seen as more of a safety problem than speeding," he said. "The attitude toward speeding is a lot like what the attitude toward drinking and driving was 30 years ago: 'What's the big deal? Everybody does it.'"
The review appears in the latest issue of The Cochrane Library, a publication of The Cochrane Collaboration, an international organization that evaluates medical research. Systematic reviews draw evidence-based conclusions about medical practice after considering both the content and quality of existing medical trials on a topic.
The authors analyzed 26 studies of the effects of speed cameras and other laser and radar speed-detection devices. The studies came from Australia, Denmark, Germany, Canada, Hong Kong, the Netherlands, New Zealand, the United Kingdom, Norway, Finland and the United States.
Of the studies, all published between 1984 and 2004, 21 measured the effect of the speed-detection devices on the number of crashes in the immediate vicinity. In these, the number of all crashes dropped by 14 percent to 72 percent once the devices were installed; crashes involving injury fell by 8 percent to 46 percent. Crashes that caused fatalities or serious injuries went down by 40 percent to 46 percent.
Some of the studies suggested a "halo" effect in which drivers began to slow down even when they were driving on streets a distance away from the devices; the number of all crashes in wider areas dipped by 9 percent to 35 percent.
Several studies also reported a dip in speed levels. In some areas of Washington, D.C., for instance, the number of drivers going above the speed limit by 10 mph or more dropped by 82 percent after the devices were installed.
But the review authors weren't impressed with the studies overall. Using a Cochrane-designed rating system that measures the reliability of research, they determined that only seven studies were of "good" quality. Ten were "fair" and the remaining nine were "poor."
While the authors write that speed cameras and similar devices are a "promising intervention" to reduce injuries and deaths on the road, they add that "more studies of a scientifically rigorous nature are necessary to provide a stronger evidence base that these interventions are worthwhile."
More research doesn't seem likely to change the mind of Eric Skrum, communications manager of the National Motorists Association. His organization, which he says has a 6,500-driver membership, opposes "photo enforcement" on the road.
When speed cameras or red-light cameras are installed, that's a sign that an intersection or road isn't designed properly, Skrum said. "Rather than going for engineering solutions first, too many communities are seeing this as the perfect solution," he said. He says that communities "take advantage of the situation and start ticketing people left and right. That doesn't really solve the problem."
Enforcement cameras can even make things worse on the road, he said: "People become camera-shy and they're slamming on their brakes."
Rader, the Insurance Institute for Highway Safety spokesman, said Skrum's argument misses the fact that speeding is a factor in about a third of all fatal crashes. "Contrary to the conventional wisdom, speeding is a big safety problem. Obviously, police can't be everywhere, can't do speed enforcement everywhere. But speed cameras can."
Wilson C, et al. Speed enforcement detection devices for preventing road traffic injuries. The Cochrane Database of Systematic Reviews 2006, Issue 2.
The Cochrane Collaboration is an international nonprofit, independent organization that produces and disseminates systematic reviews of health care interventions and promotes the search for evidence in the form of clinical trials and other studies of interventions. Visit http://www.cochrane.org for more information.
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