An extensive six-year analysis of over 10,000 Canadian drivers involved in motor vehicle collisions has revealed that cannabis has surpassed alcohol as the most common impairing substance detected through post-crash blood testing.
The National Drug Driving Study 2024, conducted by the University of British Columbia, examined blood samples from drivers across various provinces between 2018 and 2023. The study found that 54 percent of injured drivers tested positive for at least one impairing substance, with 16.6 percent testing positive for cannabis and 16 percent for alcohol.
The report states, “Driving after cannabis use appears to be an emerging problem in Canada and may now be more prevalent than driving after consuming alcohol.” However, it emphasizes that driving under the influence of alcohol remains a more significant issue due to the high crash risk associated with it.
Additionally, the study highlighted that Atlantic Canada has a higher proportion of injured drivers who are likely to have used cannabis compared to other regions.
During the study period, 26 percent of drivers from Nova Scotia, New Brunswick, and Newfoundland and Labrador tested positive for cannabis, while 22 percent tested positive for alcohol. Overall, 70 percent of drivers tested positive for drugs or alcohol, surpassing the national average.
Lead author Dr. Jeff Brubacher, from the University of British Columbia’s department of emergency medicine, expressed concern about the prevalence of impaired driving in Atlantic Canada, calling it a significant issue in the region.
The study noted that the number of drivers with cannabis in their system has increased since legalization in 2018. Dr. Brubacher emphasized the dangers of combining alcohol and cannabis, describing it as a harmful combination.
The study highlighted the effects of cannabis intoxication on driving, such as attention deficits, slowed reaction time, and impaired tracking ability. It also noted that habitual cannabis users may develop tolerance to some of these effects.
Dr. Brubacher emphasized the importance of the study for emergency room physicians, public health officials, police, and organizations promoting safe driving practices. He hopes that the data collected can guide enforcement efforts and educate the public about the risks of impaired driving.
