Could you pass a virtual driving test after consuming cannabis?
A new study from the University of McGill outlines how young drivers appear to face greater challenge while driving under the influence of cannabis. That is to say, they are more prone to crashes when they have THC in their system. Interestingly, among cannabis consumers and advocates, the general opinion on getting high before driving off are much less judgemental than that for drinking and driving.
According to the Canadian Cannabis Survey, released in 2017, almost 50 percent of those surveyed believed that getting high would NOT affect their ability to drive. Nearly 40 percent of cannabis smokers even admitted to operating a vehicle within two hours of lighting up. A 2016 survey found that only 10 percent of Canadians believed they were ok to drive, even if they had consumed alcohol and were over the legal limit.
The Not-So-Shocking News About Driving While High
The results of the study out of the Research Institute of the McGill University Health Centre (RI-MUHC) and McGill University are clear, “Young Canadians are more at risk of a vehicle crash even five hours after inhaling cannabis.” So those folks who admitted to smoking weed and driving within two hours of each other were more than likely impaired when they took to the wheel.
The McGill study put young drivers, between the ages of 18 and 24, under the influence of THC, from the equivalent of one joint. They were then subject to a virtual driving test, whereby real-life distractions and on-the-road experiences came into play. The participants’ reaction time and performance were tested at various intervals (up to five hours) after ingesting the psychoactive compound.
Researchers admit, that under controlled driving conditions, driving was more or less the same as the baseline (a sober driving test). But, and this is important, as soon as driving conditions replicated real-life distracted driving situations, their capabilities immediately took a downward turn. These impairments from smoking a joint, lasted up to five hours after smoking.
A recent study, sponsored by the Canadian Automotive Association (CAA), is serving to shift formerly held opinions about driving while high. Many previous studies have shown little to no impairment in virtual driving simulations. However, these simulations were conducted on experienced drivers, driving on a pre-set course. Young drivers could be more influenced and impaired by cannabis while on the road than their adult counterparts, due to lack of experience, increased risk-taking, and lower tolerance to THC.
Driving Drunk Versus Driving High
For decades now, Canadian youth have been taught about the dangers of drinking and driving, and these lessons have worked. Alcohol-related accidents have been steadily on the decline since 1986. But unfortunately, these lessons often failed to include the risks of using other substances and getting behind the wheel. It just wasn’t on people’s radar, until Canada started talking about recreational weed. With studies like the one out of McGill now showing the hazardous levels of impairment caused by THC, many Canadians are wondering about how drunk drivers compare to high ones.
There is no side by side comparison looking at a drunk driver versus a stoned one. For the longest time, lawmakers were much more focused on studying drunk drivers, and there was little funding to spare for other substances. But the tides are shifting, and alcohol is no longer the leading cause of impairment in some places. In the U.S. today, THC is now the most commonly detected intoxicant in cases of impaired driving.
In a 2010 exploration entitled, “The Effect of Cannabis Compared with Alcohol on Driving,” the authors looked at how each substance affects impairment. Alcohol impairs: psychomotor performance, short-term memory, pursuit tracking, hazard perception, reaction time, attention, hand-eye coordination, and more. It increases risk-taking behavior, including risk-taking while driving and with only low levels of alcohol-blood levels. When people drink, there is a direct relationship between the amount of alcohol consumed and the degree of impairment.
Cannabis, on the other hand, has a less direct or easily understood relationship between dose and impairment. Cannabis causes what the authors call “highly automatic driving functions.” In every imaginable way, cannabis causes driving impairments. This includes “tracking, motor coordination, visual functions, and particularly complex tasks that require divided attention.”
Despite this concise summary, there are still some conflicting reports about cannabis-related impairment. For example, some studies of cannabis in controlled driving simulations show little to no impairment, and yet the McGill study very clearly demonstrates intoxication and decreased reaction time. It may depend on tolerance, driving experience, and other uncontrolled physiological differences between the study participants.
What is widely agreed upon, is that for impairment, there are exponential increases in measurable impairment when alcohol and cannabis are combined. According to the review, alcohol, and cannabis, “when used together, have additive or even multiplicative effects on impairment.” Driving under the influence of both substances is drastically more risky than driving under the influence of either alone.
Youth Warned to Steer Clear of Cannabis When Driving
More people than ever before are using cannabis in the US and Canada, and based on the statistics coming out of the US, more people than ever before are getting behind the wheel. There have already been multiple reported arrests of Canadian drivers under the influence of THC, some of which have been under the legal age of consumption. Young drivers are particularly vulnerable to the effects and impairments of cannabis, yet lawmakers across the continent are struggling to catch up to the new reality.