About 16 percent of U.S. drivers tested positive for drugs on weekend nights in 2007, with marijuana detected the most, according to a federal study that screened for such substances for the first time.
After marijuana, which was found in 8.6 percent of drivers, the next most commonly used drugs were cocaine and over-the- counter and prescription medications, each found in 3.9 percent, the National Highway Traffic Safety Administration said today. The survey included almost 11,000 drivers.
“This troubling data shows us, for the first time, the scope of drugged driving in America,” Gil Kerlikowske, director of the Office of National Drug Control Policy, said in a statement. “It puts us all at risk and must be prevented.”
Methamphetamine was the fourth most common, found in 1.3 percent of nighttime drivers. The list of drugs covered illegal, prescription and over-the-counter products, NHTSA said.
NHTSA cautioned in a research note that drug presence doesn’t necessarily imply impairment. Drug traces such as those in marijuana can be found weeks after last use, the note said. The agency said it is doing more research on any relationship between drug traces and impairment.
About 2.2 percent of drivers on weekend nights had a blood alcohol concentration at or above the legal limit of 0.08, the study showed. That was down from 4.3 percent in 1996, 5.4 percent in 1986 and 7.5 percent in 1973, according to NHTSA in Washington.
Impaired Motorcycle Riders
Some 5.6 percent of motorcycle drivers tested at or above 0.08, more than twice the 2.3 percent for passenger-vehicle operators, NHTSA said. About 3.3 percent of pickup truck drivers exceeded the legal limit, the second-highest percentage after motorcycle riders, the agency found.
The percentage of male drivers above the legal limit was 42 percent higher than the percentage of female drivers.
The 2007 voluntary survey included random stops at 300 U.S. locations, with most data collected between 10 p.m. and midnight on Fridays and Saturdays, and from 1 a.m. to 3 a.m. on Saturdays and Sundays.
Almost 11,000 drivers entered survey sites. Of those, 9,413 gave breath tests, while 1,496 refused or were unable to. About 7,719 gave oral fluids, and 3,276 gave blood samples.
Police directed traffic to the survey site and otherwise didn’t interact with drivers, NHTSA said.
Researchers previously had not tested for drug use in the once-a-decade analysis that goes back to 1973. The agency said developments in analytic toxicology helped researchers do the assessments.
By John Hughes
July 13, 2009