Recreational use of marijuana has been legalized recently in many areas in North America. One of the effects that interests insurance companies is the change in vehicle accident experience. This study summarizes information on the car accident experience in Canada and several US states and provides robust estimates of the legalization impacts based on recent methodological developments for the analysis of observational data, including machine learning and other data-driven techniques. The study did not detect statistically significant impacts of legalization on the car accident fatality rate, insurance claim frequency, or average cost per claim. The estimated seasonality and pre-legalization dynamics in Canadian vehicle insurance statistics continued after legalization without a significant change. In the U.S., temporal patterns of human activity (such as yearly, weekly, and daily cycles) and inclement weather are much better predictors of the vehicle accident experience than marijuana legalization.
Vyacheslav Lyubchich (Mon,) studied this question.
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