Canadian Researchers: Legal Cannabis Hasn’t Caused More Traffic Injuries

Legalizing cannabis in Canada has not made the roads less safe, according to a University of Northern British Columbia (UNBC)-led research team.

In a new study published in November, lead author Dr. Russell Callaghan of UNBC’s Northern Medical Program and fellow researchers wrote that cannabis legalization in 2018 cannot be linked to increases in traffic injuries in two examined Canadian provinces.

Callaghan and his team looked at weekly provincial counts of traffic-injury emergency department (ED) presentations of all drivers and youth drivers in Alberta and Ontario, the only two Canadian provinces capturing all ED visits occurring in the general population. Youth were defined as individuals aged 14-17 years in Alberta and 16-18 in Ontario.

The project reviewed all Ontario and Alberta ED data from April 1, 2015 to Dec. 31, 2019. Researchers found that following cannabis legalization, there was no evidence of significant changes in traffic-injury ED visits among all drivers or youth drivers.

“Implementation of cannabis legalization has raised a common concern that such legislation might increase traffic-related harms, especially among youth,” Callaghan said in a statement.

“Our results, however, show no evidence that legalization was associated with significant changes in emergency department traffic-injury presentations.”

The study was recently published in Drug and Alcohol Dependence, an international peer-reviewed scientific journal.

“Our findings are somewhat surprising. I predicted that legalization would increase cannabis use and cannabis-impaired driving in the population, and that this pattern would lead to increases in traffic-injury presentations to emergency departments,” Callaghan said.

“It is possible that our results may be due to the deterrent effects of stricter federal legislation, such as Bill C-46, coming into force shortly after cannabis legalization. These new traffic-safety laws imposed more severe penalties for impaired driving due to cannabis, alcohol and combined cannabis and alcohol use.”

The project included researchers from UNBC, the Center for Addiction and Mental Health (CAMH) in Toronto, University of Victoria and Dalhousie University. Callaghan and his team are currently conducting a follow-up study to examine the impacts of cannabis legalization on traffic fatalities in Canada looking at data from 2010 to 2020. The results of this follow-up study should be available in the summer of 2022.

The study was supported in part by a Canadian Institutes of Health Research Catalyst Grant for Cannabis Research in Urgent Priority Areas.