Studies link higher crash rates with states that legalized marijuana
The Insurance Institute for Highway Safety and the Highway Loss Data Institute announced Thursday that crashes in states with legalized recreational marijuana have increased up to 6 percent.
IIHS and HLDI are set to present two studies Thursday on collision crashes in states where marijuana is legal at the Combating Alcohol- and Drug-Impaired Driving summit at IIHS' Vehicle Research Center in Ruckersville, Va.
IIHS and HLDI said that 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 collision loss data from January 2012 to October 2017.
David Harkey, president of IIHS-HLDI, told Automotive News his team has been looking at the issue of marijuana use and crash risk since states started considering the legalization of recreational marijuana a few years ago.
Harkey said 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.
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. and in light of Canada legalizing recreational use of marijuana on Wednesday. Bloomberg said Canada became the first Group of Seven country to legalize recreational marijuana, giving it a massive head start in the global marijuana market some peg at $150 million.
Although marijuana's role in crashes is not as clear as the link between alcohol impairment and crashes, Harkey said he thinks the public needs to be informed about potential collisions, especially as more states discuss legalization.
"We know a lot of states are considering making recreational marijuana available," Harkey said. "They just need to be aware of what we're seeing in the data.
"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."
He also said that his team is doing more detailed studies to figure out the level impairment associated with marijuana and corresponding crash risks. Harkey is hoping for results in the next year or two.
"From some of the roadside survey work we have done so far, we're seeing marijuana is not only being used at night or in the evenings, it is also being used at other times of the day and during daylight hours," he said. "We have real concerns about the level of impairment that's going to be occurring at all times of the day."