Toronto, there’s never been a better time to try your hand at driving while high — safely, of course.
Using state-of-the-art driving simulators, the Centre for Addiction and Mental Health (CAMH) is currently running four studies looking at the impacts of cannabis use on driving.
It’s the most studies the research centre has ever run on the topic concurrently, according to Patricia Di Ciano, a CAMH scientist and assistant professor at the University of Toronto.
Di Ciano is leading two studies, investigating how well people drive the morning after getting stoned, and how consuming cannabis and tobacco together can impact driving.
The two other studies are looking into the effects of consuming edibles before driving, and how different age groups respond to being high behind the wheel.
TorontoToday was given special access to try the newest simulator, sober, on Tuesday morning, but eligible Torontonians with a valid driver’s license can sign up for any of the four CAMH studies to try it under the influence.
The simulator is made up of three large monitors that wrap around the driver’s field of vision, with two smaller monitors showing the view out of the back passenger windows. The gear shift on this simulator had been replaced by a tablet — but the driver’s seat, steering column and pedals appeared just as a normal vehicle’s would.
Di Ciano loaded a simulation of a two-lane highway for TorontoToday to drive on. While there was no sensation of acceleration in the simulator and the graphics were reminiscent of an early 2010s video game, there were some features that made the drive feel realistic.
For instance, the seat shook when cars in the oncoming lane passed by, and again when TorontoToday accidentally drove off the road while taking a photo behind the wheel.
Overall, the experience felt faithful to what driving in real life is like.
Safety is the main reason why studies like this use driving simulators, but Di Ciano notes there are added benefits. For instance, the simulator is able track speed changes and steering movements much more accurately than if participants were in a real-life car.
Research has shown that driving simulators aren’t perfect at re-creating the experience of driving, but the accuracy of results tended to increase the higher the dosage of cannabis consumed.
Improving research on cannabis and driving
With cannabis legalization in the rear-view mirror, Di Ciano said there’s been increasing interest to study marijuana, especially from federal agencies looking to make roads safer like Transport Canada and Public Safety Canada.
While the consensus among scientists is that cannabis does impair driving, there’s less literature on how different methods of getting high, such as consuming edibles or vaping, can impact driving, as well as the interaction between cannabis and other substances like nicotine and alcohol.
There’s also been conflicting research on whether cannabis legalization has led to more hospitalizations from traffic injuries.
To accommodate studies of this kind, CAMH has acquired three driving simulators over a period of about 10 years, Di Ciano said. The machines cost around $150,000, she said.
According to Di Ciano, the driving simulator is a bit of a fan favourite, and may have enticed some participants to engage in more studies.
“People think it's fun — they like it,” she said. “People come back, I think, because they like to drive the simulator.”
But the experience of driving the simulator while stoned has also given some participants a greater appreciation of the dangers, Di Ciano said.
“People often say, ‘Oh, I see now what it would be like to drive after using cannabis,’ and they get a sense that’s not a good idea,” she said.
Study participants tend to weave in and out of lanes more often, and have poorer reaction times after consuming cannabis, the CAMH scientist explained. This can lead some cannabis-impaired drivers to drive slower than they might while sober — the opposite of what scientists have observed from drunk drivers.
“Cannabis tends to slow speed and alcohol tends to increase speed,” Di Ciano said. “The reason why people slow down… from what they tell us, is that they realize they’re not driving as well, so they slow down to compensate for it.”
But just because an impaired driver is driving slower, or is more conscious of their impairment, doesn’t mean they aren’t still a danger on the road, Di Ciano said.
“People definitely perceive that cannabis is safer than alcohol for driving. It might be a little bit safer than alcohol, but it's still not safe,” she said. “It's never a good idea to use either cannabis or alcohol before getting behind the wheel.”
Driving under influence all too common
CAMH used to ask study participants if they had ever driven while under the influence of cannabis, and Di Ciano said “an alarming number of people did.”
According to a survey prepared in 2022 for Public Safety Canada, about one third of Canadians who used cannabis within the previous year said they had driven under the influence. About 40 per cent of those respondents said they didn’t feel impaired, while 23 per cent said they thought they could drive safely.
One of the studies that Di Ciano is currently leading looks at the impact of smoking both cannabis and tobacco before driving. She suspects the study will show that consuming both substances will lead to worse driving outcomes than smoking cannabis or tobacco alone, but this has not yet been confirmed.
“There's also evidence out there that tobacco may counteract cannabis, because they have completely opposite mechanisms of action in the brain,” Di Ciano said. “So it's also possible that tobacco may mitigate the effects of cannabis.”
If any reader feels emboldened to test this theory, don’t do so on the road. Consider signing up for the study instead.
