OREANDA-NEWS One-third of young adults aged 19 and 20 report riding in a motor vehicle with an impaired driver at the wheel at least once in the past year, a new study reports.

Marijuana use, not alcohol, was more likely to be the cause of the impairment.

Researchers used data from the NEXT Generation Health Study, a nationally representative survey of US adolescents and young adults focusing on health and behavior. They analyzed responses from people one to two years out of high school who were asked about a variety of health topics, including risky behavior and substance use.

One-third of the group surveyed said they had taken a ride with an impaired driver. More specifically, in response to a question about riding in a vehicle driven by someone who had had an alcoholic drink or drug, 23 percent of the young adults said they had done so with a driver who had smoked marijuana. One in five say they had ridden along with an alcohol-impaired driver.

Researchers say the study is the first to ask about the impaired driver’s age and relationship. Respondents were more likely to be riding with a peer than an adult—21 percent versus 2.4 percent for marijuana, 17 percent versus 4 percent for alcohol.

The fact that so many young adults have been passengers in a car with an impaired driver is concerning, researchers say, not only because taking the risk once increases the chance of doing so again, but because it also predicts that the passenger will at some point drive impaired themselves.

The findings underscore the need to raise awareness and combat the perception that impaired driving is acceptable, says Federico Vaca, a professor in the emergency medicine department at Yale University and in the Child Study Center. He directs the DrivSim Lab, a research initiative that seeks to reduce car crashes.

Motor vehicle crashes are the leading cause of death and injury among teens and young adults, according to the Centers for Disease Control and Prevention.

Additional contributors are from the National Institutes of Health and Colorado State University.

The researchers report their results in the Journal of Studies on Alcohol and Drugs.

The National Institutes of Health and the Maternal and Child Health Bureau of the Health Resources and Services Administration funded the EXT Generation Health Study.