"Did Michigan’s Legalization of Recreational Marijuana and Ohio’s Legalization of Medical Marijuana Increase Marijuana OVI Arrests in Ohio?"

The question in the title of this post is the title of this new paper authored by Peter Leasure and Dexter Ridgway ay Ohio State's Drug Enforcement and Policy Center (which I help direct).  Here is its abstract:

The current study used Ohio State Highway Patrol data to explore whether Michigan’s legalization of recreational marijuana and Ohio’s legalization of medical marijuana increased arrests for operating a vehicle while impaired (OVI) by marijuana in Ohio.  Overall, a conservative examination of the results did not support the hypothesis that Michigan’s legalization of recreational marijuana and Ohio’s legalization of medical marijuana increased marijuana OVI arrests in Ohio.  However, strong conclusions should not be drawn from this study as the results must be replicated using data from other Ohio law enforcement agencies and perhaps extended time periods.  Additionally, our results may not be generalizable to other outcomes such as OVI-related crashes.