The effects of orally ingested Delta-9-Tetrahydrocannabinol on drivers' hazard perception and risk-taking behaviours: A within-subjects study of medicinal cannabis users.
Psychopharmacology March 1, 2026 Taren Mieran, Andrew Hill, Mark S Horswill et al.
Medicinal cannabis users who consumed THC oil did not show a decline in their actual ability to detect hazards while driving, but their confidence in that ability dropped. There was no link between how well they thought they performed and how well they actually performed, regardless of THC consumption. After taking THC, users drove slower and kept longer following distances, suggesting they compensated for perceived impairment. Gap acceptance and self-rated driving skills remained unchanged. The findings indicate that frequent medicinal cannabis users may not accurately judge their own hazard perception performance, yet they adopt cautious driving behaviors after THC use.