Cannabis and traffic collisions: A case crossover study of patients presenting to tertiary care centres in Toronto and Halifax

Impaired driving is a leading cause of morbidity and mortality in Canada, and is an important issue to researchers, policymakers, and the public. Epidemiological evidence points to the profound effect of alcohol on road safety, and a number of important initiatives to combat this problem have been introduced. Concern about the effects of other drugs on road safety, in particular cannabis, has been growing in recent years; however, much less is known about this issue. The purpose of this research project is to understand the effects of cannabis consumption, either alone or in conjunction with alcohol, on the risk of traffic collision among patients presenting to emergency departments in Halifax and Toronto. This study is the first of its kind to explore the effects of cannabis on collision risk in multiple sites and provinces, and one of only a handful that will have examined the issue in Canada. The results of this research have clear implications on road safety and population health. Collectively, this project is an important multidisciplinary effort between clinicians, epidemiologists, social scientists, and policy makers, and fulfills CIHR's objective to fund interdisciplinary, collaborative, and policy relevant research with the goal of improving the health of Canadians.