Who's To Blame For Traffic Accidents? Cannabis? Weather? Insurance Actuaries Weigh In

Does marijuana decriminalization lead to more traffic accidents?

According to the new report from the Canadian Institute of Actuaries (CIA), and the Casualty Actuarial Society (CAS), no, it doesn’t.

Per the study, cannabis reform is not linked to a significant increase in traffic accidents or accident severity. The more precise predictors of car accidents have to do with temporal patterns of human activity (annual, weekly, and daily cycles) and inclement weather.

The report, Assessing the Impact of Marijuana Decriminalization on Vehicle Accident Experience, analyzed the impact of cannabis decriminalization on vehicular fatality rates, insurance claim frequency, or average cost per claim in the U.S. and Canada, and found no impact on this data, writes Insurance Journal.

Report Highlights

The research, which relied on a study of previous literature and new data review, concluded that even though cannabis impairment does influence driving behavior, the behavior is not always riskier. For example, a study from 2016 showed that cannabis users aware of the impairment were more careful, driving at slower speeds, etc.

These results are somewhat in line with driving simulator data published in June 2022 in the journal Traffic Injury Prevention, which revealed that those who use marijuana regularly drive better after all, compared to occasional users.

There are, however, previous studies showing opposing results. For example, research from 1993-2003 (the National Highway Traffic Safety Administration’s Fatality Analysis Reporting System) revealed that the 5% of drivers aged 20-50 who tested positive for marijuana had higher chances of speeding, driving erratically and failing to respect traffic signs.

The actuarial report also suggested that some of the prior studies have various limitations, such as analyzing only one area for example, or using only one statistical principle. “Some other publications consider relative change without the overall impact,” per the report.

Dr. Vyacheslav Lyubchich, the report author explained the comprehensiveness of this study. “The methods used in this research include improved statistical models, machine learning, and other data science techniques. The models used high-resolution weather data to account for the effects of weather factors.” 

For the statistical models, it was used U.S. and Canadian data from 2016-2019 such as official reports of collisions of private vehicles and losses in Canada, fatal accidents, and weather factors in the United States.

Does Cannabis Reform Lead To Impaired Driving? 

It is important to remember another study, published in July 2022 undertaken by the Coalition for Cannabis Policy, Education, and Regulation (CPEAR) that claims marijuana legalization does not increase impaired driving. According to the report, the effect of legalization on driving under influence (DUI) is “either insignificant or declines a year after the legal market was implemented,” though the organization highlighted that “more research and better data collection” is needed.

This means that whether marijuana is legal, decriminalized or illegal, the number of impaired driving cases remains the same. 

Photo: Courtesy of Clark Van Der Beken on Unsplash