So you’ve had a few drinks and you’re in your car, ready to go home. Instead, you end up in a hospital because you can’t drive in a straight line. what gives?
Bad driving is one of the leading criminal causes of death in Canada, accounting for 59 percent of non-homicide-related criminal deaths nationwide in 2019, according to a Statistics Canada report. Alcohol and drugs were involved in nearly 24 percent of Alberta’s fatal collisions last year, Cpl. Richard Nowak of the Alberta RCMP’s traffic headquarters said in an email.
Drugs like alcohol and cannabis impair our ability to drive by messing with neurotransmitters, explained neuroscientist Declan Ali of the University of Alberta.
“A lot of the brain is devoted to some aspect of motor control,” he said, which requires the right neurons to fire at the right time and in the right order.
When you consume alcohol or cannabis, the alcohol and THC molecules begin to bind with various proteins on neurons in your brain and spine, triggering some and suppressing others, Ali explained. The effect is like dropping a bucket of water on a computer – your nerve transmissions are impaired, interfering with your ability to move, think and understand.
Tim Stockwell of the Canadian Institute for Substance Use Research said that researchers have found that alcohol results in slower reaction times and reduced ability to perform multiple tasks at once (such as looking at the side of the road and the car in front of you). This prompts you to drive faster, as it suppresses your ability to perceive risks.
These and other effects make you more likely to die in a collision, reports the Alberta government—your risk of death increases threefold at a blood-alcohol content level of 0.05 percent, and six-fold at 0.08 percent, compared to being sober. and 11 times at 0.1 percent.
Stockwell said THC prompts people to avoid greater exposure and run slower, but also inhibits reaction times. It may be slightly less dangerous than alcohol when it comes to poor driving, but still increases your chances of getting into an accident. A recent study from the University of Calgary found that alcohol and cannabis did not cancel each other out when combined, and actually caused more harm than either.
Stockwell said that everyone processes drugs differently, so there’s no hard and fast rule about how much of a drug you need to take so you don’t get screwed. As little as a drink or two can do harm.
Ali said drugs like alcohol alter all aspects of your functioning, including your ability to notice such changes. This means you may think you are able to drive safely after a few drinks, while in reality you may not.
“It’s not a good idea to get behind the wheel after eating these things,” Ali said of cannabis and alcohol.
Ali and Stockwell said other drugs like caffeine or cocaine will not counteract the effects of alcohol or cannabis, as they affect different parts of your nervous system.
“You’re still extremely vulnerable, but you believe you’re not,” Stockwell said.
Ali said the only way your body can counteract the drugs is to wait for enzymes like alcohol dehydrogenase to break down. Scientists have yet to find a way to speed up this process without causing other problems.
Nowak said any amount of drugs or alcohol can cause harm, and that driving poorly is a crime.
“Driving impaired is never worth the risk,” he said – share a cab or a ride, or have a designated driver instead.
“If you have consumed any harmful substance, do not drive.”