A clinical trial shows that young adults who smoke a joint should wait at least five hours before driving or face a higher chance of crashing their car.
The trial, conducted by McGill University and paid for by CAA, showed “performance declined significantly in key areas such as reaction time, even five hours after inhaling the equivalent of less than one typical joint,” according to a statement sent to media.
Adults 18-24 who participated in the trial did so in a driving simulator, and tests showed their performance deteriorated even hours later.
“This new trial provides important Canadian evidence that cannabis can affect the skills needed to drive safely, even five hours after consuming, and underscores the idea that if you feel you’re not safe to drive, you’re correct,” said Erika Miller, communications consultant with CAA Manitoba.
“We should treat cannabis the same way we treat alcohol: if you indulge, find another way home like a designated driver, ride-share or transit, or stay where you are and don’t drive for at least five hours afterwards.”
Participants who had consumed cannabis showed no significant declines in performance when driving in the simulator with no distractions, according to the study. But as soon as drivers were subjected to distractions, those who had cannabis saw their skills go down drastically, the study showed.
The study was published Monday in the Canadian Medical Association Journal.
CAA polling has found that a significant number of young Canadians — one in five — believe their driving skills are as good or better when stoned as they are when sober.
“This rigorous experimental trial adds to a growing body of scientific literature on cannabis use and driving,” said study co-author Isabelle Gélinas, a researcher at McGill’s School of Physical and Occupational Therapy.
“The findings provide new evidence on the extent to which driving-related performance is compromised following a typical dose of inhaled cannabis, even at five hours after use.”
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