The effects of medical marijuana laws on cannabis-involved driving. (September 2018)

• Record Type: Journal Article
• Authors: Sevigny, Eric L.
• Is Part Of: Accident analysis and prevention. Volume 118(2018)
• Page Start: 57
• Page End: 65
• Publication Date: 2018-09
• Subjects: Medical marijuana laws -- Cannabis-involved driving -- Differences-in-differences -- Multiple imputation -- Fatality analysis reporting system; Accidents -- Prevention -- Periodicals; Accident Prevention -- Periodicals; Accidents -- Prévention -- Périodiques; 363.106
• DOI: 10.1016/j.aap.2018.05.023
• Languages: English
• ISSNs: 0001-4575

Abstract

Highlights: Investigates effect of medical marijuana laws (MMLs) on marijuana-involved driving. MMLs in general are not significantly associated with marijuana-involved driving. States with dispensaries see a 14% increase in odds of marijuana-involved driving. Dispensary effect is small: 87–113 more drivers test positive for marijuana yearly. Abstract: This study uses data from the Fatality Analysis Reporting System and a differences-in-differences model to examine the effect of state medical marijuana laws (MMLs) on cannabis-involved driving among U.S. drivers involved in a fatal crash between 1993–2014. Findings indicate that MMLs in general have a null effect on cannabis-positive driving, as do state laws with specific supply provisions including home cultivation and unlicensed or quasi-legal dispensaries. Only in jurisdictions with state-licensed medical marijuana dispensaries did the odds of marijuana-involved driving increase significantly by 14 percent, translating into an additional 87 to 113 drivers testing positive for marijuana per year. Sensitivity analyses reveal these findings to be generally robust to alternate specifications, although an observed spillover effect consistent with elevated drugged driving enforcement in bordering states weakens a causal interpretation. Still, reasonable policy implications are drawn regarding drugged driving prevention/enforcement and regulations governing dispensary delivery services and business siting decisions.