Association of Recreational Cannabis Laws in Colorado and Washington State With Changes in Traffic Fatalities, 2005-2017

Source: 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

Key Points

Question  Have traffic fatalities increased after the implementation of recreational cannabis laws in Colorado and Washington State?

Findings  Using a synthetic control approach, this ecological 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.

Meaning  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).