Study Says Legal Marijuana Does Not Correlate to an Increase in Traffic Fatalities

The idea that legalizing marijuana consumption increases the chances of traffic related fatalities is quickly becoming harder to believe.

Increasingly studies are disproving this common assumption, most recently via a study by Andrew Young a graduate student at Kansas State University.

Andrew Young | Kansas State University

Young examined traffic fatality data over a 23 year period and used two models to formulate his findings. Young applied a panel statistical regression to twenty-three years of state-level data on travel, road safety, and the legality of marijuana then applied a difference-in-differences model to demonstrate the effect of marijuana legalization on traffic fatalities, comparing the changes over time in legalized states relative to control states which have not legalized marijuana. The difference-in-differences analysis covered an eight-year timeline, starting five years before the state in question legalized marijuana.

Andrew Young | Kansas State University

Young said, “Specifically, this research combines twenty-three years of state traffic data with information on the contemporaneous legal status of marijuana, for both medical and recreational use, to estimate two models of road safety.”

In Arizona a state with legal medicinal use average traffic fatalities mirrored those of Wyoming and South Dakota. In both states cannabis is still an illegal substance.

Andrew Young | Kansas State University

A stark contrast in fatal accident rates did exist in Colorado when compared to Georgia and Iowa in 2001, but that was prior to medical cannabis legalization and the numbers were nearly identical in 2003 and remained similar for Georgia and Colorado in years following.

“According to the models, the recent upward trend of traffic fatality rates nationwide is not a result of medical marijuana legalization. In fact, the legalization of marijuana is not found to be a predictor of traffic fatalities,” Young wrote.

Andrew Young | Kansas State University

In the District of Columbia traffic fatalities dropped in 2010 following approval of medical cannabis by the city council. Comparatively, both Virginia and Utah saw greater numbers of traffic related deaths. Both states prohibit marijuana.

Young’s conclusion? “The results of the analysis suggest that there is no statistically significant relationship between marijuana legalization and fatal crashes.”