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Status Report, Vol. 37, No. 5 | SPECIAL ISSUE: AUTOMATED ENFORCEMENT | May 4, 2002 Subscribe

Cameras reduce speeding on D.C. streets

Diahann Hill

Speed cameras in use for more than 20 years in numerous countries are reducing travel speeds. Now the same benefit is accruing from photo radar in a U.S. community, new research shows.

Washington, D.C. implemented a citywide speed camera program beginning last summer. The police department has deployed five vehicles equipped with cameras, moving them among 60 enforcement zones throughout the city. Residential streets, major arteries, highways, and school and work zones are being targeted.

The cameras snap pictures of the rear license plates of vehicles exceeding the speed limit by more than a set amount, usually 10 mph, and violators are ticketed by mail. After a 30-day warning period during July 2001, police began mailing violation notices to the owners of speeding vehicles identified by the cameras. Fines range from $30 to $200 per violation, depending on how much faster than the speed limit a vehicle was traveling.

Institute researchers measured travel speeds on seven neighborhood streets before the cameras were deployed and again at the same sites six months after deployment. At all of the sites, the proportion of motorists going fast enough to warrant getting a ticket went down. The reductions ranged from 38 to 89 percent.

At the same time, the proportion of motorists going more than 10 mph faster than the speed limit at eight sites in Baltimore, Maryland, stayed about the same or increased slightly. Cameras aren't being used in Baltimore.

"It's a very clear finding. It's an across-the-board benefit for the District's camera program," says Richard Retting, the Institute's senior transportation engineer. He explains that the city's speed cameras "aren't fixed in place at locations around town. They're mounted on unmarked police cars and operated by officers who set up the cameras and monitor them while they're operating. An officer can shut down camera operation if traffic conditions warrant. That's one of the advantages of this kind of system."

Another advantage is that the vehicle-mounted cameras are easy to move from one location to another. "By moving the cameras around, there's a general influence on vehicle speeds across the city, including where the cameras aren't operating," Retting notes.

Lt. Patrick Burke, traffic coordinator of the police department, says "the goal isn't to ticket motorists." This is why "there are in excess of four dozen signs that say 'traffic law photo enforced' posted around the city. The idea is to get people to think twice because they might get their license plate snapped if they speed."

Unlike conventional radar equipment, which police aim at a stretch of road on which numerous vehicles may be traveling, the speed cameras in use in the District of Columbia pinpoint particular vehicles. This method removes potential confusion about which vehicle was speeding.

About 75 countries rely on cameras to enforce speed limits (see "Who cares about a camera if you're not speeding?" June 19, 1999). The cameras have reduced both high travel speeds and crashes. But cameras aren't yet in use in many U.S. communities.

"Using cameras would enhance safety," Retting points out. "Research conducted in Canada, Australia, Europe, and now in the District of Columbia indicates that motorists are less likely to speed in communities where camera enforcement is employed."

Percentage of vehicles going more than 10 mph faster than the speed limit
before and after speed cameras in Washington, D.C.

Graph image

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