Study: Medical Cannabis Doesn’t Negatively Impact Driving Performance
No responsible cannabis advocate wants intoxicated drivers on public roadways. With that being said, just because someone has metabolized THC in their system does not automatically mean that they are intoxicated, and public policies need to reflect that scientific fact.
One jurisdiction that has struggled with this area of public policy is Victoria, a state in Australia. The Australian state was automatically banning the driving privileges of medical cannabis patients if they were found to have THC in their system while operating a motor vehicle on public roadways. Fortunately, that policy was changed starting on March 1st, 2025.
“Drivers who use medicinal cannabis in Victoria will no longer be subject to automatic licence bans under a new law coming into effect in the state. From the 1st of March, such motorists will have the opportunity to argue in court that they weren’t impaired while driving.” reported SBS News in its local coverage.
The policy change is backed by the findings of a recent study conducted in Australia which found that medical cannabis use does not negatively impact driving performance in experienced users. Below is more information about the study and its findings via a news release from NORML:
Queensland, Australia: Patients who consume botanical cannabis over extended periods do not exhibit significant changes in their simulated driving performance, according to data published in the Journal of Safety Research.
Australian researchers assessed patients’ simulated driving performance at baseline and 45 minutes after they vaporized prescribed doses of cannabis flowers. (Under Australian law, physicians may authorize cannabis products to patients unresponsive to conventional prescription treatments.)
“After vaporizing one dose of their prescribed cannabis flower, participants exhibited no significant changes in performance on any of the video-based tasks (hazard perception skill, gap acceptance, following distance or speed) compared to baseline,” investigators reported.
The study’s authors concluded, “The findings … suggest that a dose of vaporized cannabis (consumed in accordance with prescription) may not affect hazard perception ability or driving-related risk-taking behavior among medicinal cannabis patients.”
The study’s findings are consistent with those of several others determining that daily cannabis consumers, and patients especially, exhibit tolerance to many of cannabis’ psychomotor-influencing effects. According to the findings of a literature review published in the journal of the German Medical Association, “Patients who take cannabinoids at a constant dosage over an extensive period of time often develop tolerance to the impairment of psychomotor performance, so that they can drive vehicles safely.”
Full text of the study, “The acute effects of vaporized cannabis on drivers’ hazard perception and risk-taking behaviors in medicinal patients: A within-subjects experiment,” appears in the Journal of Safety Research. Additional information is available in the NORML Fact Sheet, ‘Marijuana and Psychomotor Performance.’
