Driving under the influence of cannabis has become more common than alcohol-impaired driving among young drivers, and many teens believe cannabis has little effect on driving. Few interventions address cannabis-impaired driving among youth, and those that exist have rarely been tested experimentally. A pilot study at UMass Amherst with 62 high school juniors and seniors found that a short drive in a driving simulator while wearing cannabis-impairment goggles significantly increased teens’ perceived risk of cannabis-impaired driving. This project will test whether adding a classroom session, adapted from the AAA curriculum “Shifting Gears: The Blunt Truth About Marijuana and Driving,” produces larger and longer-lasting changes in risk perception than the simulator experience alone, and will identify what helps or hinders delivery of this kind of education in high schools.
The project will use a two-condition randomized design at multiple high schools in Massachusetts and Vermont, with a target of 240 juniors and seniors aged 16 to 18 randomly assigned within each school. Both groups will complete a 10-minute simulated drive wearing impairment goggles in the UMass Distractology trailer; one group will first receive a 30-minute adapted Shifting Gears session and the other a classroom module unrelated to cannabis. Perceived risk and intentions about cannabis-impaired driving will be surveyed before the session, immediately after, and at a 4 to 6 week follow-up, and simulator measures such as speed exceedances and lane deviations will be recorded. The curriculum will be adapted with AAA Northern New England and AAA Northeast, schools will be recruited through the CLOSE Community Coalition of Longmeadow Public Schools and the Vermont Highway Safety Alliance, and structured interviews with school administrators, health educators and prevention coordinators will inform how the program can be delivered in schools. Results will be analyzed with mixed-effects models that treat school as a random effect, and interviews through thematic analysis.
