Marijuana use linked to increased crashes

Marijuana use linked to increased crashes

Legalizing recreational marijuana use in Colorado, Oregon and Washington has resulted in an increase of collision claim frequencies.

A new Highway Loss Data Institute (HLDI) study shows that crash claims are about 3 percent higher overall than would have been expected without legalization.

More drivers admit to using marijuana, and it is showing up more frequently among people involved in crashes.

Though there is evidence from simulator and on-road studies that marijuana can degrade some aspects of driving performance, researchers haven’t been able to definitively connect marijuana use with more frequent real-world crashes.

Some studies have found that using the drug could more than double crash risk, while others, including a large-scale federal case-control study, have failed to find a link between marijuana use and crashes.

Studies on the effects of legalizing marijuana for medical use also have been inconclusive.

HLDI conducted a combined analysis using neighboring states as additional controls to examine the collision claims experience of Colorado, Oregon and Washington before and after law changes.

HLDI’s new analysis of real-world crashes provides one look at the emerging picture of what marijuana’s legalization will mean for highway safety as more states decriminalize its use.

“Worry that legalized marijuana is increasing crash rates isn’t misplaced,” says David Zuby, executive vice president and chief research officer of the Insurance Institute for Highway Safety.

“HLDI’s findings on the early experience of Colorado, Oregon and Washington should give other states eyeing legalization pause.”