Logan, UT: The enactment of adult marijuana regulations in Washington state is associated with a decrease in alcohol-related motor vehicle accidents in neighboring Idaho counties, according to the findings of a working paper published by the Center for Growth and Opportunity at Utah State University.
The paper, authored by University of Oregon economist Benjamin Hansen, reported that the decline was most significant in those counties closest to the Washington border, but was no longer evident in counties residing six hours away from the border.
The author concluded, "These findings are consistent with increased access to marijuana leading to substitution away from alcohol to marijuana."
The paper’s findings are consistent with a prior paper identifying a decrease in traffic accidents in Colorado following the regulation of medical cannabis – a decline which authors attributed to a reduction in alcohol consumption. By contrast, a more recently published paper identified an association between retail cannabis sales in Colorado in Washington and a slight uptick in fatal crashes compared to control states.
Full text of the working paper, "Are Marijuana and Alcohol Substitutes? Evidence from Neighboring Jurisdictions" is available online.