Crashes are up by as much as 6 percent in Colorado, Nevada, Oregon and Washington, compared with neighboring states that haven’t legalized marijuana for recreational use, new research from the Insurance Institute for Highway Safety (IIHS) and Highway Loss Data Institute (HLDI) shows. The findings come as campaigns to decriminalize marijuana gain traction with voters and legislators in the U.S., and Canada begins allowing recreational use of marijuana this month.
The two new studies will be presented today at the Combating Alcohol- and Drug-Impaired Driving summit, hosted by IIHS and HLDI at the Vehicle Research Center. The summit brings together highway safety and law enforcement experts to discuss the prevalence and associated risk of alcohol- and drug-impaired driving, as well as strategies to combat impaired driving.
Colorado and Washington were the first states to legalize recreational marijuana for adults 21 and older with voter approval in November 2012. Retail sales began in January 2014 in Colorado and in July 2014 in Washington. Oregon voters approved legalized recreational marijuana in November 2014, and sales started in October 2015. Nevada voters approved recreational marijuana in November 2016, and retail sales began in July 2017.
HLDI analysts estimate that the frequency of collision claims per insured vehicle year rose a combined 6 percent following the start of retail sales of recreational marijuana in Colorado, Nevada, Oregon and Washington, compared with the control states of Idaho, Montana, Utah and Wyoming. The combined-state analysis is based on collision loss data from January 2012 through October 2017.