The annual cannabis holiday and fatal traffic crashes

Abstract

BACKGROUND: Cannabis use has been linked to impaired driving and fatal accidents. Prior evidence suggests the potential for population-wide effects of the annual cannabis celebration on April 20th (‘4/20’), but evidence to date is limited. METHODS: We used data from the Fatal Analysis Reporting System for the years 1975-2016 to estimate the impact of ‘4/20’ on drivers involved in fatal traffic crashes occurring between 16:20 and 23:59 hours in the USA. We compared the effects of 4/20 with those for other major holidays, and evaluated whether the impact of ‘4/20’ had changed in recent years. RESULTS: Between 1992 and 2016, ‘4/20’ was associated with an increase in the number of drivers involved in fatal crashes (IRR 1.12, 95% CI 0.97 to 1.28) relative to control days 1 week before and after, but not when compared with control days 1 and 2 weeks before and after (IRR 1.05, 95% CI 0.92 to 1.28) or all other days of the year (IRR 0.98, 95% CI 0.88 to 1.10). Across all years we found little evidence to distinguish excess drivers involved in fatal crashes on 4/20 from routine daily variations. CONCLUSIONS: There is little evidence to suggest population-wide effects of the annual cannabis holiday on the number of drivers involved in fatal traffic crashes.

Publication
Inj Prev
Sam Harper
Sam Harper
Associate Professor of Epidemiology

My research interests include impact evaluation, reproducible research, and social epidemiology.

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