Study: Driving Under the Influence of Marijuana a Greater Threat to Teens Than Alcohol

Marijuana use is on the rise among teens and is currently at its highest level among eighth- to-12th-graders in 30 years. Perhaps equally disturbing is that one-in-five (19 percent) teen drivers reports that they have driven under the influence of marijuana, according to the most recent teen driving study by Liberty Mutual Insurance and SADD (Students Against Destructive Decisions). In fact, marijuana influence is significantly more prevalent among teen drivers than alcohol, as compared to the 13 percent of teens surveyed who report that they have driven after drinking.

The study, which Liberty Mutual and SADD have regularly conducted since 2000, highlights a dangerous misconception: many teens don’t even consider marijuana use as a distraction to their driving. More than one-third (36 percent) of teens who have driven after using marijuana say the drug presents no distraction to their driving. Also alarming, among the teens who say they have driven after drinking, 19 percent of them believe alcohol use does not present a driving 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,” said Stephen Wallace, Senior Advisor for Policy, Research, and Education at SADD. “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.”

Indeed, in a prior Liberty Mutual Insurance/SADD study in 2009, 78 percent of teens were at the other end of the spectrum, characterizing marijuana use as “very” or “extremely” distracting to their driving. However, in the most recent study two years later, the percentage of teens who felt this high level of concern declined to 70 percent.

“Teens are faced with potentially destructive decisions everyday and don’t always make the best ones,” said Dave Melton, a driving safety expert with Liberty Mutual Insurance and managing director of global safety. “It’s our job as mentors, parents, role models or friends to effectively communicate with them to ensure they are armed with the right information and aware of the dangers of marijuana and other substances, especially while driving.”

Friends do play a significant role, as most teen drivers say they would stop driving under the influence of marijuana (90 percent) or alcohol (94 percent) if asked by their passengers. Yet even teen passengers are seemingly less concerned about riding in a car with a driver who has used marijuana than with one who has used alcohol. While a significant majority (87 percent) of teen passengers would speak up and ask the driver to refrain from getting behind the wheel after drinking, only 72 percent of teen passengers would do the same for a driver who has used marijuana. Girls are far more likely to speak up to the driver than boys are in either circumstance.

Liberty Mutual Insurance and SADD commissioned ORC International to conduct a qualitative and quantitative study to measure teen driving attitudes and behaviors. The study was initiated with a series of four focus groups held in Harrisburg, Pa., and San Francisco, Calif., in October 2010, followed by a survey of 2,294 teens in eleventh and twelfth grades from 28 recruited high schools across the country in January 2011. Overall findings for the study can be interpreted with a 95 percent confidence interval with an error margin of +/- 2.02 percent.