NTSB chief warns that people underestimate Marijuana's impact on drivers Image Cannabis News July 22, 2024 NTSB Chair Urges Parents to Warn Teens About Marijuana-Impaired Driving After Fatal Crash. Jennifer Homendy's comments come after the NTSB determined a 2022 Oklahoma crash that killed six teens was caused by a driver who likely was impaired by recent marijuana use and distracted by passengers. A Medical Cannabis News Recreational Marijuana News Health News