Cannabis use affects drivers even after 5 hours: McGill study

As Canada legalised marijuana today, a study says driving under marijuana influence is dangerous

Today, as Canada became the world’s second and largest country with a legal marijuana marketplace, concerns remain about the unknown dangerous consequences.

Among them are concerns about consuming cannabis and compromised driving ability. Medical marijuana has been legal in the country since 2001.

A new study by McGill University in Montreal appears to reinforce such concerns.

The study says: “Young Canadians are more at risk of a vehicle crash even five hours after inhaling cannabis, according to results of a clinical trial conducted at the Research Institute of the McGill University Health Centre (RI-MUHC) and McGill University, and funded by the Canadian Automobile Association (CAA).”

“The research found that performance declined significantly, in key areas such as reaction time, even five hours after inhaling the equivalent of less than one typical joint. The participants’ driving performance, which was tested in a driving simulator, deteriorated as soon as they were exposed to the kinds of distractions common on the road.”

“The message is simple: If you consume marijuana, don’t drive. Find another way home or stay where you are.”

“This new trial provides important Canadian evidence that cannabis can affect the skills needed to drive safely even five hours after consuming,” said Jeff Walker, chief strategy officer for the Canadian Automobile Association (CAA).

“The message is simple: If you consume, don’t drive. Find another way home or stay where you are.”

The clinical trial by the Montreal-based Research Institute of the McGill University Health Centre and McGill University examined the effects of cannabis on driving reflexes among occasional marijuana smokers (users who smoked cannabis at least once in the past three months, but not more than four times per week) aged 18 to 24 years old.

45 participants took part in the study, 21 women, 24 men, who were put in a driving simulator and exposed to a variety of different common distractions on the road.

The study’s participants completed simulations after one, three and five hours of inhaling a standard puff through a vaporizer (100-mg dose) and a typical joint (300-500 mg dose of dried cannabis).

Participants were also tested sober to gauge a baseline.

The results, published in an open-access medical journal by the Canadian Medical Association, found that there was a “significant impairment on complex and novel driving-related tasks.”

Another recent survey had found that an alarming number of Canadian drivers admit to operating a vehicle after smoking cannabis.

The researchers were unsurprised by the results that cannabis impacted driving. The numbers on how long drivers are impacted was unexpected. Ongoing studies are being conducted, looking at the cannabis affect on drivers up to 24-hours after consuming.