Key Takeaways
- The legalization of cannabis in Canada in 2018 led to concerns about cannabis-impaired driving.
- Police-reported impairment cases increased by 31% from 2019-2023 compared to the 2009-2018 trend.
- The growth in impairment cases was correlated with the number of police trained in drug recognition and COVID-19 pandemic restrictions.
- Alcohol remained the most common impairment category, but its share of all cases dropped from 98% in 2009 to 80% in 2023.
- The increase in drinking drivers caught by police was four times the increase in drugged drivers.
Introduction to Cannabis-Impaired Driving
When Canada legalized cannabis in October 2018, there were many concerns about its potential impacts, including the risk of cannabis-impaired driving. Before legalization, police were already catching more drug-impaired drivers each year, leading to worries that more stoned drivers would appear on the road after legalization. To lower this risk, the federal government updated its driving laws, making impairment by combinations of alcohol and drugs, or by unspecified substances, illegal. The government also helped police to better enforce these laws by giving them more power to obtain breath and blood samples from drivers and funding more training to help them recognize symptoms of drug impairment.
Analyzing Police Data
To better understand the impact of cannabis legalization on impaired driving, research analyzed the annual rates of impaired driving cases that police investigated between 2009 and 2023. The reporting covered four substance categories: alcohol, drugs, drugs-and-alcohol combined, and unknown substances. Note that "drugs" includes cannabis but also other chemicals like opioids and amphetamines. Publicly available data, unfortunately, don’t name the drugs involved. The data showed that during the 15-year study period, alcohol remained the most common impairment category, but its share of all cases dropped from 98% in 2009 to 95% in 2017 and to just 80% in 2023.
Changes in Impairment Rates
Up until 2018, the total impairment rate also fell each year. However, in 2019, rates jumped substantially, with police reporting 31% more impairment cases during 2019-2023 than the 2009-2018 trend had projected. The impairment increases varied between provinces, with no significant change in Québec and Saskatchewan, but rates doubling in British Columbia and Newfoundland. Percentage-wise, the drugs category saw the most growth, averaging 42% higher during 2019-2023 than had been projected. But alcohol impairment rose too, averaging 17% above its previous trend. The increase in drinking drivers caught by police was four times the increase in drugged drivers.
Correlations and Explanations
The analysis showed that the impairment changes were correlated most strongly with the number of police trained in drug recognition. Not surprisingly, when provinces gave police more training, they caught more impaired drivers. The restrictions that provinces imposed during the COVID-19 pandemic showed the second biggest correlations with impairment. But interestingly, alcohol and drugs diverged: when provinces tightened restrictions, they got less impairment from alcohol but more from drugs. Presumably, lockdowns meant fewer bars open, and so fewer people driving home drunk. But perhaps lockdowns also meant more laid-off workers using drugs at home before going grocery shopping.
Conclusion and Recommendations
Overall, Canadian police reported noticeably more drug-impaired and alcohol-impaired driving after 2018. But the growth seemed related mostly to enhanced enforcement and pandemic disruptions, rather than to legalized cannabis. And fortunately, the long-term decline in impaired driving resumed in 2020. All road users benefit from this continuing decline. To maintain this trend, it is essential for individuals to consume responsibly, whether their preferred intoxicant is booze, weed, or something else. Using designated drivers or public transit to get home is crucial, and flashing colored lights look much nicer on a tree standing in your home than on a police car pulling you over. By being responsible and taking necessary precautions, we can all play a role in maintaining a safe and impaired-driving-free environment.