Knowledge and Resource Hub
02 October 2018

Early evidence on recreational marijuana legalization and traffic fatalities

This research examines the early evidence on the consequences of the legalisation of recreational marijuana which has recently occurred in several US states. Despite public support for the legalisation, significant concerns have been raised about a potential increase in collision frequencies and marijuana related fatalities. Initial reports have identified significant increases in collision frequencies in Colorado, Washington, and Oregon after marijuana markets opened in those states, as well as increases in the nominal number of drivers involved in fatal crashes who test positive for marijuana (marijuana-related fatalities). In contrast, the current research found that since legalising marijuana, Colorado and Washington have not experienced significantly different rates of marijuana- or alcohol-related traffic fatalities relative to controls.