In the wake of Canada’s looming pot legalization on Wednesday, a new study says young drivers are at increased risk of a car crash five hours after getting high.
The clinical trial out of McGill University and funded by CAA and published Monday, looked at the impact of weed on the driving ability of 18- to 24-year-old occasional users in Canada.
“There are a significant amount of Canadians who think they are as good or better at driving high than they are sober,” Ian Jack, CAA managing director of communications and government relations, said.
“We always thought anecdotally that was not true but wanted to prove that.”
Under simulated driving conditions, researchers tested the performance of the participants in intervals up to five hours after they had consumed weed. They were also tested without cannabis in their system to set a baseline.
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The researchers found that “a regular dose of cannabis” did not have an effect on simple driving tasks like braking, steering and lane-keeping. However, there were “significant impairments” on more complex driving tasks, such as merging or spotting a pedestrian on the road.
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“The most absolute basic of functions seemed to be OK, but as soon as everyday distractions were added, it made a difference,” Jack said. “Merging, turning into an intersection, a pedestrian crossing, someone riding a bike … as soon as anything like that happened, the driving performance dropped significantly.”
A large percentage of the young drivers in the study also said they did not feel as safe driving after consuming cannabis, even five hours after use, he added.
The findings come after a Statistics Canada survey released in August found an “alarming” number of Canadians have driven a vehicle while high on cannabis.
According to the second quarterly national cannabis survey, 14 per cent of cannabis users who have a driver’s licence admitted they got behind the wheel within two hours of consuming cannabis at least once.
A 2017 CAA poll also found that 18 per cent of its members aged 18 to 34 said they were “as good” drivers stoned as they are sober. Two per cent of the respondents said they were “better” drivers stoned.
“Simply put, it’s not a good idea to drive after consuming cannabis,” Jack said. “It should be treated like we do alcohol; make an arrangement, call a cab or have a designated driver. There are real consequences.”
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Jack added although the study looked into the results of cannabis and driving after five hours, more testing needs to be done after hour six, seven, eight, etc.
“That was as far of what was tested, that does not mean there is a ‘get of jail free card’ even at five hours and one minute.”
The McGill clinical trial, funded by CAA, examined participants between the ages of 18 and 24 who were recreational users of cannabis (i.e. used cannabis at least once in the past three months, but not more than four times per week). The trial tested their driving-related performance on four different days using a driving simulator. Testing was randomized to occur one hour, three hours and five hours after they had consumed cannabis. They used a medical grade vaporizer to consume a dose of 100 mg dried cannabis flowers containing 13 per cent THC over several inhalations. A typical joint is 300-500 mg of dried cannabis.