Cannabis-positive motor vehicle crash drivers increased sharply from 2017 to 2020

Analysis of 683,184 motor vehicle crash drivers at US trauma centers found that 28.8% tested positive for drugs or alcohol, with 36.3% of those testing positive for multiple substances. Marijuana was the second most common substance (41.6% of positive tests, after alcohol at 47.1%). Cannabis-related MVCs increased significantly from 10.2% in 2017 to 14.6% in 2020 (P<0.001), with the most prominent rise among adolescents.

Retrospective analysis of the American College of Surgeons-Trauma Quality Improvement Program database over 4 years (2017-2020). Included all patients presenting after an MVC as a driver. Trend analysis performed for positive blood or urine toxicology results across substance categories.

This is one of the largest analyses of substance-impaired driving in the US, showing that cannabis-related crashes are rising faster than any other substance category, particularly among adolescents. The trend accelerated even during a period of expanding legalization.

As cannabis legalization expands across the US, the parallel rise in cannabis-positive crash drivers raises questions about whether current DUI prevention policies adequately address drugged driving. The adolescent trend is particularly concerning given that no state has legalized recreational use for minors.

Positive drug screens do not prove impairment at the time of the crash; THC can be detected days after use. Cannot determine causation between cannabis use and crash occurrence. Database covers trauma center admissions only, excluding less severe crashes and fatalities.