For decades, efforts to reduce impaired driving in Canada have focused largely on alcohol.
But new data suggest the country’s impaired-driving landscape has changed. Drivers who tested positive for drugs are now involved in a larger share of fatal crashes than those who tested positive for alcohol.
“For decades, alcohol has been the primary focus of impaired driving strategies, but the data are telling us a new story that requires different solutions,” Ward Vanlaar, COO of the Traffic Injury Research Foundation, said in a press release.
But experts say the findings should be interpreted with caution because testing positive for a drug does not necessarily mean someone is impaired by it.
“There is no doubt that the trend is concerning in terms of public safety,” said Steve Sullivan, chief executive officer of MADD Canada, in an email to Canadian Affairs.
“[But] it is important to note that the presence of drugs does not mean equal impairment in all cases.”
Drug driving
The findings come from a report released July 31 by the Traffic Injury Research Foundation, which analyzed fatal crashes across Canada over a 23-year period.
Alcohol-related fatal crashes have declined over the past several decades — a trend researchers attribute to stronger law enforcement, changing social attitudes and initiatives such as designated driver programs.
At the same time, crashes involving drivers who tested positive for drugs have steadily increased.
In 2023, 571 people died in crashes involving a driver who tested positive for drugs. That was up from 487 in 2019 and more than double the 230 deaths recorded in 2000.
Overall, about two in five road deaths involved a driver who tested positive for drugs in 2023, compared with about one in 10 in 2000.
The analysis is based on drivers who tested positive for cannabis, illicit drugs, prescription medications and over-the-counter drugs.
Careful interpretation
Jeffrey Brubacher, an emergency physician and traffic injury researcher at the University of British Columbia, says the overall increase in drug-positive drivers is “pretty convincing.”
But he notes the data must be read with caution.
“‘[D]rug positive’ and ‘impaired by drugs’ are not the same thing,” he said. “A low level of a drug in one’s blood does necessarily mean someone is impaired — just that they used the drug at some point.”
Cannabis, for example, can remain detectable long after use.
“The increase in ‘cannabis positive drivers’ after [cannabis] legalization likely reflects more people using cannabis — with no information on when they used it relative to crashing,” he said.
Brubacher says post-mortem testing has limitations because drugs can shift from body tissues into the bloodstream after death, making concentrations difficult to interpret.
He also says changes in testing practices over time, including broader drug screening and more sensitive laboratory equipment, may explain part of the increase.
Despite the increase in drug-positive drivers, Brubacher and Sullivan say alcohol remains a major road safety concern.
“Alcohol is still our biggest problem,” said Brubacher.
Policy response
While police have effective tools such as roadside breath tests to detect alcohol impairment, identifying drug impairment remains more difficult.
“Our tests for drug impairment are not as simple or effective as a breathalyser,” said Brubacher.
Sullivan says Canada has expanded police tools over the past two decades, including roadside sobriety testing, drug recognition evaluations and legal THC limits. But he said more work is needed on enforcement and public awareness.
“Clearly there needs to be more done in terms of public awareness about the risks of drug-impaired driving and the ability of police to detect drug-impaired drivers,” he said.
Brubacher said Canada also needs better research and monitoring to understand the scope of drug-impaired driving.
“We need more research to identify better tests. We need education so drivers — especially young drivers — are aware of the risks of drugs and driving. And we need to continue monitoring the problem more effectively,” he said.
