Date of Conferral





Public Policy and Administration


Matthew Jones


Washington State and Colorado were the first states to legalize recreational marijuana. According to the Washington Traffic Safety Commission, the number of drivers who tested positive for marijuana in traffic fatalities increased 48% from 2013 to 2014, and marijuana legalization may have influenced this increase. Since marijuana legalization is new to the United States, the effects of this change in policy are untested in the literature. The purpose of this quantitative study using a regression point displacement design was to examine the relationship between traffic fatalities involving cannabinoids in Washington State before and after marijuana legalization. Rational choice theory and perceptual deterrence theory provided the framework for the study. Existing state level data of traffic fatalities from the National Highway Traffic Safety Administration's Fatality Analysis Reporting System were analyzed using regression point displacement. Pre and post legalization Washington state fatalities were compared against 43 control groups where marijuana has not been legalized for recreational use. Results from ANCOVA analysis indicated no statistical difference between Washington State and other nonlegalized states in traffic fatalities involving cannabinoids. This is one of the first studies exploring the effects of marijuana legalization on public safety. These results suggest marijuana legalization may not contribute to the increase in traffic fatalities. Findings may provide legislators and traffic safety stakeholders with information in creating legislation legalizing marijuana as well as strategy and a research agenda to address traffic fatalities.