Several studies over the years from organizations like the National Institute on Drug Abuse have found a correlation between marijuana use and an uptick in at-fault accidents.4 CDC data has supported this conclusion as well.
However, a new report from the Canadian Institute of Actuaries and the Casualty Actuarial Society (CAS) contradicts previous findings. Using machine learning to identify patterns in Canadian and U.S. data from 2016 to 2019, the organization looked at the effect of the decriminalization of marijuana on vehicle accidents — and what they found about driving performance may surprise you.
The CAS researchers discovered that while being high on marijuana affects driving behavior, it may not be a bad thing. In fact, the study indicated some cannabis users were actually safer when they drove high, using slower speeds and longer following distances.
Looking at 10 regions in Canada, CAS concluded there were no statistically significant changes in the average cost per insurance claim or the frequency of claims since the legalization of marijuana in Canada in 2018. While results in the U.S. varied by state, CAS found that marijuana legalization and/or decriminalization failed to lead to a statistically significant change in fatality data. This accounted for weather and other factors that typically affect fatality data over weeks and years.5
Of course, just because some people who drive while impaired don’t suffer negative consequences doesn’t mean no one does. Still, it will be interesting to see how the data progresses as more U.S. states legalize and decriminalize recreational marijuana use. Will there be more evidence proving marijuana can make people better, not worse, at driving? Only time will tell.