Among drivers in Connecticut who died in a car crash, the percentage who tested positive for marijuana increased following the legalization of recreational marijuana, according to a recent study published in the American Journal of Forensic Medicine and Pathology. This study adds to the body of evidence that indicates that the legalization of marijuana is associated with a rise in traffic fatalities. 

Among 1,168 decedents who were drivers and had deaths that were classified as accidental, 530 occurred prior to legalization (January 1, 2018–June 30, 2021) and 638 occurred after legalization (July 1, 2021–December 31, 2024), with the legalization of recreational marijuana taking effect on July 1, 2021. Among these deaths, toxicology tests were performed for 1,113. During these two time periods, the percentage that tested positive for marijuana increased from 32.8% prior to legalization (165 of 503) to 37.9% after it (231 of 610). 

Moreover, the percentage of pedestrians who were killed by motor vehicles and tested positive for marijuana increased from 11.2% prior to legalization (18 of 161) to 20.6% after it (42 of 204). 

Other studies have also concluded that the legalization of recreational marijuana is associated with a rise in traffic fatalities. A 2020 study in JAMA Internal Medicine estimated that the legalization of recreational marijuana would be associated with 6,800 additional traffic fatalities. A 2022 study concluded that “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.” And a 2021 study found that the percentage of traffic deaths in Colorado that involved marijuana increased from 9.0% in 2000 to 21.5% in 2018. 

As more people use and drive under the influence of marijuana, communities can expect a rise in the number of marijuana-involved traffic fatalities to follow.