Laws permitting medical cannabis did not have any significant effect on the number of medical cannabis users involved in fatal car crashes over a 22-year period, according to a June 2018 study.
Research Study: 'The effects of medical marijuana laws on cannabis-involved driving'
• 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.
The study, in peer-reviewed journal Accident Analysis and Prevention, published by Elsevier, examined cannabis use in fatal crashes between 1993 and 2014, though its author, Georgia State University associate professor Eric Sevigny, was careful to caution that the study does not determine whether users were high at the time of the crash — but only whether they had consumed cannabis.
“In general we don’t find medical marijuana laws impact fatal crashes for better or worse,” Sevigny said. “Some supply provisions have a small increasing effect, and from a policy perspective we could see that as a negative.”
The study did not examine whether there was a link between recreational cannabis laws and fatal crashes, because there wasn’t enough data available during that time frame.
State laws regarding medical cannabis use had no effect on the number of cannabis users involved in fatal crashes, either in reducing fatal crashes or increasing their likelihood, the study found.
However, state-licensed dispensaries increased the number of fatal crashes by 14 percent. Though the increase was statistically significant, it did not result in a much larger number of drivers with cannabis in their system.
“States with dispensaries, we find there’s a significant positive increase in cannabis-positive drivers,” said Sevigny, an associate professor of criminology at Georgia State University whose research focuses on crime and public policy.
“Even though it’s significant, when you’re dealing with large datasets, the impact is small,” Sevigny said. “Some of the numbers in there, somewhere on the order of 100, we might see 100 additional drivers who test positive for cannabis in a given year who otherwise wouldn’t have in other dispensary systems.”
Though the reason behind the increase isn’t clear, Sevigny speculated that perhaps medical cannabis users have to drive longer distances to buy medical cannabis. Some states may also leave a lot of discretion up to cities and counties on whether they allow dispensaries, meaning some people may have to drive farther to buy cannabis products.
To reduce the number of possibly impaired drivers state legislators should consider and improve ways to allow for the delivery medical cannabis to patients, Sevigny said. Before legalizing anything, policymakers should also use public messaging about impaired driving targeted toward young people akin to drunken driving public service announcements, which have proven to be effective, he added.
“If the state decides to roll out dispensaries, there are a couple considerations. One is to have some pre-roll out prevention planning,” Sevigny said.
The study, made available online in June 2018, will be published in the September 2018 print edition of Accident Analysis and Prevention.
Research Study 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.
About Mr. Eric Sevigny:
Eric Sevigny is Associate Professor of Criminal Justice and Criminology at Georgia State University. He received his Ph.D. in Public and International Affairs from the University of Pittsburgh in 2006. His research interests lie at the intersection of drugs, crime, and public policy, particularly around issues of sentencing and incarceration, the measurement of drug-related problems, the collateral consequences of mass incarceration, and the impact of medical marijuana laws on drugged driving and other outcomes. Dr. Sevigny’s research on drug problem measurement is currently supported by the Office of National Drug Control Policy. His work appears in an array of interdisciplinary journals including Criminology and Public Policy, International Journal of Drug Policy, Journal of Quantitative Criminology, Journal of Policy Analysis and Management, and Social Indicators Research.