(CBS) Is driving under the influence of marijuana less dangerous than driving drunk? Nobody knows for sure, but a new survey suggests a lot of teens seem to believe it.
The survey of 2,300 eleventh and twelfth graders - by Liberty Mutual Insurance and Students Against Destructive Decisions (SADD) - found more than one-third of teens who have driven after using marijuana say the drug doesn't distract them from driving. What's more, one in five teens admitted to driving high.
How does that compare with teen rates of drunk driving? The survey found 13 percent of teens said they had got behind the wheel after drinking, while 19 percent did not consider drinking a major distraction.
"Marijuana affects memory, judgment, and perception and can lead to poor decisions when a teen under the influence of this or other drugs gets behind the wheel of a car," Stephen Wallace, senior advisor for policy, research, and education at SADD, said in a written statement. "What keeps me up at night is that this data reflects a dangerous trend toward the acceptance of marijuana and other substances compared to our study of teens conducted just two years ago."
A 2009 survey from Liberty Mutual and SADD found 78 percent of teens considered smoking pot as "very" or "extremely" distracting to their driving.
The researchers said teen drivers' friends contribute to these rates. About 90 percent of teen drivers said they wouldn't drive high if asked by their passengers. But only 72 percent of teen passengers said they'd say something to a driver who has used marijuana, compared with 87 percent who would speak up if the driver had consumed alcohol.
Wallace told USA Today the survey's findings were "disturbing."
"We hear from young people who believe that marijuana actually makes them a safer driver, that they concentrate harder, drive slower," he said.
Some recent research shows otherwise. A new study of 50,000 drivers found motorists who smoked marijuana within three hours of getting behind the wheel were twice as likely to have a car accident, compared to sober motorists,
Ain October found that 30 percent of fatally injured drivers tested positive for drugs other than alcohol, with marijuana topping the list.
Some studies have found otherwise. According to the Huffington Post, an earlier study by Hartford Hospital in Connecticut and the University of Iowa found that people who smoked pot 30 minutes before driving did not react much differently than they had before using marijuana.
NORML, the National Organization for the Reform of Marijuana Laws, wrote its own report on stoned driving in 2011, which found driving high might be riskier than driving sober, but less risky than driving drunk.
According to the National Institute on Drug Abuse, using marijuana can cause distorted perceptions, impaired coordination, difficulty with thinking and problem solving, and problems with learning and memory.