The objective of this study was to estimate the effects of marijuana legalization and the subsequent onset of retail sales on injury and fatal traffic crash rates in the United States during the period 2009–2019.
The combined effect of legalization and retail sales was a 5.8% increase in injury crash rates and a 4.1% increase in fatal crash rates. Across states, the effects on injury crash rates ranged from a 7% decrease to an 18% increase. The estimated increases in injury and fatal crash rates after recreational marijuana legalization are consistent with earlier studies, but the effects varied across states.