Associated Press - January 31, 2008 12:13 AM ET

ARLINGTON, Va. (AP) - Drivers may not like speed camera enforcement. But research shows the presence of cameras is getting drivers to slow down.

The Insurance Institute for Highway Safety has found that drivers change their behavior when they know cameras are being used. Richard Retting, a senior transportation engineer with the Institute, says the change is dramatic, immediate and spills over way beyond the specific sites where the cameras are located.

One focus of the research was on the first camera program in the U.S. to enforce speeds on a major highway. Scottsdale, Arizona, uses cameras at fixed sites along the Loop 101 beltway. After the camera program was implemented, there was a reduction in the 90% range of drivers going 75 mph or faster.

The Institute also studied the use of speed cameras on residential streets and school zones in Montgomery County, Maryland. Researchers found that the proportion of vehicles going more than 10 mph faster than posted limits fell by 70% on roads where cameras were operational.