Studies: Crash Rates Higher in Marijuana States

Vehicle crash rates rose 5%-6% in western states that have legalized recreational marijuana compared to neighboring states that haven’t, according to two studies being released today.

The results come the day after Canada legalized pot nationwide. Moves to do the same in four U.S. states—New Hampshire, New Jersey, New York and Pennsylvania—are pending. Voters in four more states—Michigan, Missouri, North Dakota and Utah—will decide in November whether to loosen their marijuana laws.

The increase in collision claims occurred in the first year after Colorado, Nevada, Oregon and Washington legalized pot, according to research by the Insurance Institute for Highway Safety and Highway Loss Data Institute. No such rise occurred in Idaho, Montana, Utah and Wyoming, where there was no change in marijuana laws.

IIHS and HLDI note that the connection between pot use and crashes isn’t as clear as for alcohol and crashes. The two institutes say a lack of consistent state-level accident reporting about drug use or testing makes detailed research more difficult.

Still, the reports were able to adjust for state-by-state differences in driver demographics, city versus country driving, weather, seasonality and several other factors.

But the two studies come to the same conclusion. “Legalizing pot for recreational use,” says David Harkey, president of both institutes, “is having a negative impact on the safety of our roads.”