The enactment of adult-use marijuana sales in Canada is not associated with any increase in motor vehicle injuries requiring hospitalization, according to data published in the journal Drug and Alcohol Dependence. 

A team of investigators affiliated with the Centre for Addiction and Mental Health and with University of British Columbia assessed emergency department records in two provinces (Alberta and Ontario) to determine trends in traffic-injury emergency department visits in the months immediately prior to and immediately after legalization. 

Authors reported: “The current study found no evidence that the implementation of the Cannabis Act was associated with significant changes in post-legalization patterns of all drivers’ traffic-injury ED visits or, more specifically, youth-driver traffic-injury ED presentations. … Given that Canada’s Cannabis Act mandated that the Canadian Parliament review the public health consequences of the Act no later than 2023, the findings of the current study can provide empirical data not only for the Canadian evaluation of the calculus of harms and benefits, but also for other international jurisdictions weighing the merits and drawbacks of cannabis legalization policies.”

The Canadian data is consistent with prior studies from the United States also showing no significant changes in traffic safety in the months immediately following the enactment of adult-use legalization. However, separate assessments evaluating longer-term trends in traffic safety following legalization have yielded mixed results.