Increase in Traffic Fatalities Linked to Cannabis Laws Vary by State Interview with:
Julian Santaella Tenorio, MSc DrPH Epidemiology

Center for Opioid Epidemiology and Policy
Division of Epidemiology, Department of Population Health
New York University Langone School of Medicine,
New York, New York What are the main findings?

car-accident-traffic-accidentResponse: This study found that recreational cannabis laws were associated with increases in traffic fatalities in Colorado (mean of 75 excess fatalities per year) but not in Washington State.  These findings suggest that unintended effects of recreational cannabis laws can be heterogeneous and may be specific to variations in how these laws are implemented
(eg, density of recreational cannabis stores). What should readers take away from your report?

Response: We observed that recreational cannabis laws were associated with increases in traffic fatalities in Colorado but not in Washington State. We offer some hypotheses for this, e.g., the  size of the marijuana industry in Colorado, evidence of cannabis tourism in Colorado, and other local aspects such as the way drug per se laws are enforced across counties.

Previous studies showed mixed results given that they provided combined effects for all states. We show that combined results do not show the full picture and that adverse unintended effects of these laws can be heterogeneous and may depend on variations in implementation of these laws. What recommendations do you have for future research as a result of this work? 

Response: Better data on non-fatal traffic fatalities is needed to be able to examine the effects of these laws on these outcomes. Is there anything else you would like to add?

Response: Any legal or illegal medication/drug that impacts neuro-cognitive and neuromotor skills can increase the risk of traffic events. Moreover, higher rates of traffic events are likely if more drivers are driving under the influence of cannabis in combination with alcohol and/or other drugs. There is really good evidence showing that cannabis combined with alcohol use is associated with greater levels of impairment for driving performance.

We have no conflict of interest to disclose.


Santaella-Tenorio J, Wheeler-Martin K, DiMaggio CJ, et al. Association of Recreational Cannabis Laws in Colorado and Washington State With Changes in Traffic Fatalities, 2005-2017. JAMA Intern Med. Published online June 22, 2020. doi:10.1001/jamainternmed.2020.1757



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Last Updated on June 23, 2020 by Marie Benz MD FAAD