Study: Traffic Fatalities Have Not Increased As A Consequence Of Legalization

OREGON: The enactment of adult use marijuana regulations in Colorado and Washington is not independently linked to an increase in traffic fatalities, according to a study published by the National Bureau of Economic Research.

Investigators at the University of Oregon compared traffic accident outcomes in Colorado and Washington following legalization to those in other states with similar pre-legalization economic and traffic trends. They reported, “We find that states that legalized marijuana have not experienced significantly different rates of marijuana- or alcohol-related traffic fatalities relative to their synthetic controls.”

Authors concluded, “In summary, the similar trajectory of traffic fatalities in Washington and Colorado relative to their synthetic control counterparts yield little evidence that the total rate of traffic fatalities has increased significantly as a consequence of recreational marijuana legalization.”

The study’s findings are similar to those of a 2017 study published in The American Journal of Public Health which reported, “Three years after recreational marijuana legalization, changes in motor vehicle crash fatality rates for Washington and Colorado were not statistically different from those in similar states without recreational marijuana legalization.”

A 2016 study reported that the enactment of medical cannabis legislation is associated with an immediate decline in traffic fatalities among younger drivers.


For more information, contact Paul Armentano, NORML Deputy Director, at: paul@norml.org. Full text of the study, “Early evidence on recreational marijuana legalization and traffic fatalities” is available from the National Bureau of Economic Research.

Study: Adult Use Marijuana Laws Do Not Adversely Impact Traffic Fatality Rates

TEXAS: The enactment of statewide laws regulating the adult use and sale of cannabis is not associated with subsequent changes in traffic fatality rates, according to an analysis of traffic safety data published today in the American Journal of Public Health.

Investigators from the University of Texas-Austin evaluated crash fatality rates in Colorado and Washington pre- and post-legalization. They compared these rates to those of eight control states that had not enacted any significant changes in their marijuana laws.

“We found no significant association between recreational marijuana legalization in Washington and Colorado and subsequent changes in motor vehicle fatality rates in the first three years after recreational marijuana legalization,” authors concluded.

Authors also reported no association between adult use marijuana legalization and the total number of non-fatal crashes.

Commenting on the findings, NORML Deputy Director Paul Armentano said: “These conclusions ought to be reassuring to lawmakers and those in the public who have concerns that regulating adult marijuana use may inadvertently jeopardize public safety. These results indicate that such fears have not come to fruition, and that such concerns ought not to unduly influence legislators or voters in other jurisdictions that are considering legalizing cannabis.”

A prior study published last year in the same journal reported that the enactment of medical marijuana legalization laws is associated with a reduction in traffic fatalities compared to other states, particularly among younger drivers.

Fatal accident rates have fallen significantly over the past two decades – during the same time that a majority of US states have legalized marijuana for either medical or social use. In 1996, the US National Highway Traffic Safety Administration reported that there were an estimated 37,500 fatal car crashes on US roadways. This total fell to under 30,000 by 2014.