A new study sheds light on the timing and effects of driving while under the influence of cannabis-infused edibles.
The study, conducted by the University of Saskatchewan with funding support from the Canadian Automobile Association (CAA), examined 50 drivers between the ages of 19 and 30, after consuming around 10 milligrams of THC.
“There is still this misconception that cannabis makes you a safer driver or it doesn’t have an impact on driving, or it’s not as dangerous as alcohol impaired driving,” said Michael Stewart, community relations consultant with CAA South Central Ontario.
Participants consumed edibles in a controlled setting before they were put on a driving simulator, Stewart says, just to see what the impacts were. From there, researchers analyzed their behaviour between 90 minutes and six hours after consumption.
“Through the study we learned that—yes, those effects were still there,” Stewart said.
An hour and a half after eating the edible, the findings revealed it impacted their speeding control lane discipline and reaction time. Nearly one third of participants were involved in a simulated collision.
When participants were asked if they felt safe to drive after eating edibles, only four per cent indicated they did 90 minutes after consumption.
“If you inhale it, the effect is somewhat more immediate, whereas with edibles, it can be sometimes quite delayed,” said Eric Dumschat, MADD Canada’s legal director.
Dumschat said it’s important to remember that edible cannabis is very different from inhaling cannabis, explaining that some people might not feel the effects immediately and consume more and more, with the high not kicking until they get behind the wheel. He said young people are more prone to this lack of knowledge.
“They are a more risk-taking demographic. You can see they are vastly overrepresented in crashes and fatalities because they sort of have that air of invincibility, that I’m a young person nothing is going to happen to me,” Dumchat said.
Toronto police told CTV News Toronto that drug use represents about 10 per cent of impaired driving arrests in 2025—a trend which has been steady for the past few years.
“Don’t drive after consuming drugs. Just don’t do it. You will not understand the level of impairment,” said TPS Chief Myron Demkiw at a press conference on neighbourhood officers Wednesday.
A CAA-conducted survey also showed 20 per cent of drivers admitted to taking cannabis before getting behind the wheel this year, with research pointing to the growing issue of poly-use (when people combine cannabis with alcohol and, increasingly, with other drugs from painkillers to MDMA).
About 78 per cent of drivers in the Ontario-focused survey indicated they felt confident in their driving skills while under the influence—a number that increased by 13 per cent from 2021.
“CAA wants to remind folks, especially ahead of the holiday season, to always drive sober and if your plans do involve consuming alcohol or cannabis, that you’re not the one who will be driving out there,” the CAA said.
The online survey surveyed 1,510 Ontario drivers aged 19 and older from June 27 to July 14, 2025.
