One-third of young adults who recently graduated from high school say they have ridden with a driver impaired by alcohol or drugs in the past year, according to a new study.

Young adults said they were more likely to ride with a marijuana-impaired driver than an alcohol-impaired driver, HealthDay reports.

“We’ve put a lot of emphasis on drinking and driving, but less effort on driving under the influence of marijuana. Maybe we need more of the latter,” study lead author Kaigang Li of Colorado State University said in a news release.

The findings are published in the Journal of Studies on Alcohol and Drugs.