Cannabis involved in one-third of fatal Maryland crash deaths

In 2023, Maryland legalized recreational cannabis use; however, understanding of cannabis involvement in motor vehicle crashes (MVCs) remains limited. We examined toxicology findings, including routine cannabis testing, and crash circumstances among drivers fatally injured in MVCs in Maryland. We evaluated data from death investigation reports by the Maryland Office of the Chief Medical Examiner in Baltimore on drivers fatally injured in MVCs between October 2024 and March 2025. Routine comprehensive toxicology screening covered more than 100 substances, including alcohol and illicit drugs. Delta-9-tetrahydrocannabinol (THC), the active impairing ingredient in cannabis, was also detected using ELISA and confirmed by liquid chromatography tandem mass spectrometry. Any confirmed substances were considered positive. We defined a positive alcohol result as a blood alcohol concentration ≥0.08 g/100 mL, based on the legal limit for driving in Maryland. We calculated frequencies of single-substance and multi-substance toxicology results. There were 90 fatally injured drivers. One-third (n=30) tested positive for alcohol, 30% (n=27) tested positive for THC and 40% (n=36) for other drugs, of which 18.9% were illicit drugs. 12 of the 30 alcohol-positive decedents (40%) were THC-positive. 15 decedents (16.7%) were positive for involved alcohol only, 22 (24.4%) were positive for other drugs only and 14 (15.6%) were positive for alcohol and/or THC with other drugs. One-third of fatally injured drivers in Maryland tested positive for THC, and nearly half of alcohol-involved cases also involved THC. Routine THC testing in crash death investigations is essential for characterising substance-related crashes and informing prevention strategies.