Association between legalization of recreational cannabis and fatal motor vehicle collisions in the United States: an ecologic study.

Background: With the recent legalization of recreational cannabis in Canada, cannabis-impaired driving is an important public safety concern. Our aim was to examine the association between recreational cannabis legalization and fatal motor vehicle collisions using data from the United States, which present a timely natural experiment of cannabis legalization.

Methods: We conducted an ecologic study using the number of fatal motor vehicle collisions and the associated number of deaths for US jurisdictions with legalized recreational cannabis (2007-2018) retrieved from the US Fatality Analysis Reporting System.