Significant citywide crash reductions have followed the introduction of red light cameras in Oxnard, California. This is the main finding of new Institute research. It's the first scientific study of the crash effects of camera enforcement in the United States.
Front-into-side crashes at intersections with traffic signals — the collision type most closely associated with red light running — fell 32 percent in Oxnard after camera enforcement began in 1997. There were 68 percent fewer front-into-side crashes involving injuries.
These results represent more than a single community's success story. They represent the first hard evidence that red light camera enforcement is making U.S. intersections safer. Earlier studies showed that cameras reduce the offense of red light running by about 40 percent (see "Camera use deters red light running in Virginia community," Dec. 5, 1998). But except for a few studies conducted in Australia, there had been little research on how red light cameras influence the risk of a crash.
Now there is. Crashes declined throughout Oxnard even though only 11 of the city's 125 intersections with traffic signals are equipped with cameras. Previous studies of red-light-running violations in Oxnard and elsewhere found similar spillover effects. That is, the violations dropped in about the same proportions at intersections with and without cameras, attesting to the strong deterrent value of red light cameras and their ability to change driver behavior.
The cameras, which are being used to enforce traffic laws in more than 40 U.S. communities, photograph vehicles whose drivers deliberately run red lights. Violators then are ticketed by mail.
"Red light cameras provide the certainty of enforcement, 24 hours a day, 7 days a week," the Institute's senior transportation engineer, Richard Retting, explains. "This has changed the way drivers behave with regard to red light running, and now we know the behavior change is affecting the bottom line, which is crash likelihood. With the well-publicized use of camera enforcement, communities can substantially reduce the number of crashes and injuries that occur at busy intersections."
A temporary increase in rear-end crashes might be expected with any enforcement method that increases compliance with traffic signals. So the fact that rear-end crashes didn't significantly increase in Oxnard is yet another positive finding.
In calculating the crash reductions, researchers took into account changes in crashes at intersections without signals in Oxnard plus crash trends in three other California cities used as controls — Bakersfield, San Bernardino, and Santa Barbara.
The mayor of Oxnard, Manuel Lopez, welcomes the results. "The sole purpose of installing cameras in Oxnard was to reduce the number of community residents injured at busy intersections by drivers who carelessly run red lights. We're delighted that the Institute's independent evaluation identifies such positive results."
Crash reductions with cameras
|-29% injury crashes
|-32% front-into-side crashes
|-68% front-into-side crashes involving injuries