When states make the use and retail sales of recreational marijuana legal, crash rates rise.
Injury and fatal crash rates jumped 6% and 4%, respectively, in California, Colorado, Nevada, Oregon and Washington following relaxation of marijuana laws compared with other Western states where recreational marijuana use was illegal. Insurance records showed a similar increase in collision claims.
“Our latest research makes it clear that legalizing marijuana for recreational use does increase overall crash rates,” David Harkey, president of the Insurance Institute and its affiliate, the Highway Loss Data Institute, said in a statement.
The new research, consistent with earlier studies that examined how legalization has affected crash rates and insurance claims, adds to the growing evidence of the connection between legalized marijuana use and increased crash risk, according to both institutes, which each conducted a separate study.
The trend is a concern to safety experts, the safety groups said, as more than a third of U.S. states have already legalized recreational marijuana for adults 21 and older, others states are considering legalization, and usage is up.
“That’s obviously something policymakers and safety professionals will need to address as more states move to liberalize their laws — even if the way marijuana affects crash risk for individual drivers remains uncertain,” Harkey added.
However, despite crash increases, research has been inconsistent regarding whether marijuana itself makes drivers more likely to crash. The latest Insurance Institute study, for example, which used data collected from more than 1,200 injured drivers in three emergency rooms in Denver, Colorado; Portland, Oregon; and Sacramento, California, showed no increased crash risk associated with the drug, except when combined with alcohol.
Previous tests conducted in simulators indicated that drivers who are high on marijuana react more slowly, find it harder to pay attention, have more difficulty maintaining their car’s lane position, and make more errors when something goes wrong than they do when they’re sober, the safety groups said. But the tests also indicated that marijuana-impaired drivers are likely to drive at slower speeds, make fewer attempts to overtake and keep more distance between their vehicle and the one ahead of them.
Legalization may be encouraging more people to drink and use marijuana together, a possible explanation for why crash rates have increased, according to the studies.
Studies comparing the simultaneous use of alcohol and marijuana in states where marijuana is legal with states where it is still against the law will be needed to test this hypothesis, the safety groups noted, adding that some early evidence has already emerged that shows self-reports of recent marijuana and alcohol use have increased, while the reported use of alcohol alone has decreased, especially in states where recreational use of marijuana is now legal.
A recent national survey conducted by the AAA Foundation for Traffic Safety also found that drivers who self-reported using both alcohol and marijuana were more likely than those who had only consumed alcohol to say they had driven while impaired and engaged in dangerous driving behaviors.
For more information about the recent study and additional research, click here.