Car safety systems effect questioned

WEST LAFAYETTE, Ind., Sept. 27 (UPI) -- A U.S. scientist says air bags and anti-lock braking systems don't reduce the likelihood of accidents because they may encourage aggressive driving.

Purdue University Professor of Civil Engineering Fred Mannering says the behavior responsible for that seeming paradox is called the offset hypotheses, which predicts consumers adapt to innovations meant to improve safety by becoming less vigilant about safety.

"When anti-lock brakes were first introduced, insurance companies noticed the accident rates for those cars increased," he said. "We decided to see whether the offset hypothesis could explain this phenomenon."

The researchers analyzed motor vehicle data from the state of Washington over a five-year period beginning in 1992.

"We used that time period because that's when air bags started getting introduced very rapidly, and we wanted to track the same drivers over that time frame to see whether the new safety features reduced their accident and injury rate," Mannering said.

"Our findings suggest the offset hypothesis is occurring and it is sufficient to counter the modest technological benefits of airbags and anti-lock brakes," he added

A paper detailing the study was published earlier this year in the Journal of Risk and Uncertainty.