Marijuana and Driving Accidents

marijuana-traffic-accidentsAccording to a researcher from the University of Toronto, the safety hazards of smoking marijuana and driving are overrated.

Alison Smiley, an adjunct professor in the department of mechanical and industrial engineering, said marijuana taken alone in moderate amounts does not significantly increase a driver’s risk of causing an accident — unlike alcohol.

She said that drivers on marijuana remain aware of their impairment and are prompted on their own to slow down and drive more cautiously to compensate, unlike alcohol that has serious effects on judgment.

“Both substances impair performance,” Smiley says. “However, the more cautious behaviour of subjects who received marijuana decreases the drug’s impact on performance. Their behaviour is more appropriate to their impairment, whereas subjects who received alcohol tend to drive in a more risky manner.”

Smiley drew her results from a “metanalysis” of existing research into the effects of marijuana on driving ability, combined with traffic accident statistics in the United States and Australia.

“There’s an assumption that because marijuana is illegal, it must increase the risk of an accident. We should try to just stick to the facts,” added Smiley.

Smiley presented her findings at a symposium of the American Academy of Forensic Sciences in Florida. Her paper was also published in Health Effects of Cannabis, a publication of Toronto’s Centre for Addiction and Mental Health, in March.

University Of Toronto (1999, March 29)