Researchers found that traffic deaths fell by an average of 12% in legal states in the three years immediately following legalization
Changes in the legal status of cannabis in US states and Canada are not associated with significant changes to traffic safety, according to an analysis published in the peer-reviewed journal Variance.
A researcher affiliated with the University of Maryland Center for Environmental Science assessed the impact of adult-use marijuana legalization on car accident fatality rates, insurance claim frequency, and average costs per insurance claim.
The study’s author did not identify any “statistically significant impacts of legalization” on any of the assessed outcomes during the study period. Rather, the author concluded that other factors, such as inclement weather and seasonal spikes in travel, are far more likely to influence trends in traffic safety.
The findings are consistent with those of a 2023 analysis, which assessed trends in fatal motor vehicle accidents in four legalization states—California, Maine, Massachusetts, and Nevada—compared to five control states: Idaho, Indiana, Kansas, Nebraska, and Wyoming.
Researchers found that traffic deaths fell by an average of 12% in legal states in the three years immediately following legalization. By contrast, deaths increased nearly 2% over this same time in the five control states. Nationwide, traffic fatalities decreased 10.6% during the study period.
Other studies have yielded inconsistent results, with some identifying a minor increase in crash rates in specific states after legalization, while others found no such change.
This analysis was reprinted from NORML. Full text of the study, “A data-based assessment of the impact of marijuana legalization on vehicle accident risk,” appears in Variance. Additional information on cannabis, psychomotor performance, and accident risk is available from the NORML Fact Sheet, ‘Marijuana and Psychomotor Performance.‘
