Drivers who die in crashes test positive for drugs 25% of the time, a new study finds.
Researchers examined data on more than 44,000 drivers in single-vehicle crashes who died between 1999 and 2009. They found that 24.9% tested positive for drugs and 37% had blood-alcohol levels in excess of 0.08, the legal limit. Fifty-eight percent had no alcohol in their systems; 5% had less than 0.08. The data were from a government database on traffic fatalities.
Study co-authors Eduardo Romano and Robert Voas of the Pacific Institute for Research and Evaluation in Calverton, Md., say their study is one of the first to show the prevalence of drug use among fatally injured drivers. Among drivers who tested positive for drugs, 22% were positive for marijuana, 22% for stimulants and 9% for narcotics.
The study also examined interaction between alcohol and drugs in fatal crashes. Researchers found no evidence that combining drugs and alcohol produced greater impairment.
"When a driver is drunk, it doesn't matter what drugs are in their system. The alcohol takes over," Romano says.
Unlike data for drunken driving, data on drugged driving are limited, says Robert DuPont, former head of the National Institute on Drug Abuse. But in 2007, the National Roadside Survey found that 16% of nighttime weekend drivers tested positive for illegal drugs. "There's still an inadequate appreciation of drugged driving separate from the alcohol problem," DuPont says.
Only 19 states have laws prohibiting any amount of drugs while operating a vehicle, according to the Governors Highway Safety Association.