A new report out of Canada suggests that cannabis legalization isn’t the likely culprit behind an increase in auto accidents.
The study from the Casualty Actuarial Society and the Canadian Institute of Actuaries says temporal patterns of human activity are to blame.
The report, Assessing the Impact of Marijuana Decriminalization on Vehicle Accident Experience, analyzes legalization’s impact on accidents in North America.
Legalization is Not to Blame
According to the data, legalization in the U.S. and Canada has not significantly impacted accident fatality rates.
Legalization did not affect insurance claim frequency or average cost-per-claim either, especially over the long term.
The report says yearly, weekly, and daily cycles and inclement weather can better predict vehicle accident experiences.
Report author Dr. Vyacheslav Lyubchich took a three-step approach to the study.
He first established relevant controls for quantifying legalization’s effect.
Next, he collected accident data such as the frequency, severity, and types of auto accidents.
Lastly, Dr. Lyubchich applied statistical techniques to measure cannabis decriminalization’s effect while controlling for confounding factors.
Dr. Lyubchich used Canadian and U.S. data from 2016-2019 for the statistical models.
Data included official collision reports for private vehicles and losses in Canada and fatal accidents and weather factors in the U.S.
“The methods used in this research include improved statistical models, machine learning, and other data science techniques,” said Dr. Lyubchich. “The models use high-resolution weather data to account for the effects of weather factors.”
The study notes that while cannabis use does affect driving behavior, it is not always riskier.
Cannabis usually makes drivers more cautious; they tend to be aware of their condition or impairment.
Citing a 2016 study, Dr. Lyubchich says high drivers tend to drive slower and not follow other vehicles as closely.
Dr. Lyubchich says past studies have yielded mixed results regarding estimating aggregated effects on crashes and fatalities.
“There are other open questions regarding marijuana-related research,” states the report, “Which may affect the way people perceive the drug, recognize different levels of tolerance, and even test people for being influenced by the drug.”