Association for Public Policy Analysis & Management

Intoxicated operation of motor vehicles is a pervasive and significant threat to public health and safety in the United States: in 2016, more than 1 million people were arrested for driving under the influence and more than 10,000 people were killed in alcohol-related car accidents (CDC 2019). As increased marijuana availability may change consumption of alcohol and opioids (Subbaraman 2016, Powell et al. 2018), policymakers and advocates have argued that marijuana legalization may decrease driving under the influence and related harms. Prior research has demonstrated a relationship between the passage of medical marijuana laws and a reduction in alcohol-related (Anderson, Hansen, and Rees 2013) and opioid-related traffic fatalities (Kim et al. 2016). These prior studies are based on state-level measures of marijuana legalization; however, in practice the availability of marijuana varies substantially both within and across states that have legalized medical or recreational marijuana. Accounting for local variation in marijuana availability will lead to better estimates of the effects of marijuana legalization on driving under the influence, and improved policymaking related to intoxicating substances.

In this paper, I use novel measures of marijuana outlet density to evaluate the effects of state-recognized sources of marijuana on DUI arrests and alcohol-related fatal accidents. Drawing from a dataset comprised of the address, opening date, and closing date of all state-licensed medical and recreational marijuana in 18 states, marijuana outlet density is measured on the county level by the percent of the population within 5, 25, and 50 miles of any state-licensed marijuana outlet. Data on DUI arrests are obtained through Uniform Crime Reports county-level dataset; data on alcohol and opioid related marijuana traffic fatalities are obtained through the National Highway Traffic Safety Administration’s Fatality Analysis Reporting System Data. Difference-in-difference analysis is used to analyze the effect of marijuana outlet density on DUI arrests and fatal accidents. When complete, this analysis will provide policymakers with vital information on the public health and safety effects of legally recognized sources of marijuana.