Probably not a big surprise here: The Insurance Institute for Highway Safety and the Highway Loss Data Institute announced on Thursday that crashes in states with legalized recreational marijuana have increased up to 6 percent.
The IIHS is set to present two studies on crashes in states where marijuana is legal at the Combating Alcohol- and Drug-Impaired Driving summit at IIHS’ Vehicle Research Center in Ruckersville, Va.
In one study, analysts estimated 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 controlled states of Idaho, Montana, Utah and Wyoming. The analysis is based on five years worth of collision loss data from, January 2012 to October 2017.
The second study analyzed crash reports from police in legalized marijuana states and found about a 5 percent increase in crash reports when compared with neighboring states that haven’t legalized marijuana yet.
Analysts controlled for differences in the rated driver population, insured vehicle fleet, the mix of urban vs. rural exposure, unemployment, weather and seasonality. They found that collision claims are the most frequent kind of claims insurers receive.
These findings come as campaigns to decriminalize marijuana gain traction with voters and legislators in the U.S.
Although marijuana’s role in crashes is not as clear as the link between alcohol impairment and crashes, folks from the IIHS think that the public needs to be informed about potential collisions, especially as more states discuss legalization.
A top IIHS spokesperson had this to say about it: “The bottom line is that there appears to be a negative impact of highway safety in legalized states, and states considering legalization need to be prepared to deal with this impact,” he said. “Regardless of the substance — whether it’s alcohol, marijuana, prescription drugs or other substances — it is still illegal to drive impaired, and we need to make sure that the public understands that we can’t be behind the wheel, period.”
The IIHS is also doing a more detailed study to figure out the level impairment associated with marijuana and corresponding crash risks. Results on that study should be coming in the next year or two.