Research suggests fewer traffic fatalities in states with legalized marijuana

February 11, 2019

Tyson Fisher


As more states move toward legalizing recreational marijuana, safety advocates are concerned about the effects it will have on traffic deaths. A recent study reveals only one additional traffic fatality a month followed by a downward trend in states with legalized recreational marijuana.

Australian researchers Tyler Lane and Wayne Hall looked into traffic deaths in three states with legalized recreational cannabis sales (Colorado, Oregon and Washington) and nine neighboring jurisdictions (British Columbia, California, Kansas, Nebraska, Nevada, New Mexico, Oklahoma and Utah). They found only one additional traffic fatality to the monthly traffic fatality rate per 1 million residents.

Although more than half of states have legalized or decriminalized marijuana to some extent, researchers focused on states that fully legalized marijuana, including commercial sales for recreational use. In those states, marijuana is more easily accessible so they are more likely to experience any increase in traffic fatalities.

Results revealed that an increase of 1.08 traffic fatalities a month per million residents. However, that was followed by a trend reduction of 0.06 fatalities per month.

Researchers acknowledged the logic behind the belief that legalizing marijuana would increase traffic fatalities. Commercial sales not only greatly expands access to marijuana, but also provides it at a lower price and higher potency, the study states. Additionally, this could increase marijuana use among those most likely to engage in complementary cannabis and alcohol use. Logically, this would result in a net increase in impaired driving.

Neighboring states would also be affected. Bordering counties are likely to experience cross-border sales, trafficking and cannabis tourists driving back to their state of residence while impaired. In fact, marijuana-related arrests and self-reported marijuana use both increased in neighboring states.

As an example of spillover effects, researchers pointed to Windsor, Ontario. After extending alcohol sales hours, traffic injuries and fatalities decreased in nearby Detroit. It is assumed the decrease is a result of fewer Canadians driving into the U.S. to drink.

“The findings are in contrast to research on medicinal cannabis, suggesting that it decreases traffic fatalities and recreational cannabis (without sales), which has not been found to have a significant effect,” the study states. “As noted in the introduction, this is due possibly to the substitution of cannabis for alcohol in the former, which may reduce net impaired driving and limited access to cannabis because of the lack of sales in the latter, minimizing the impact of cannabis use on net impaired driving.”

Accounting for the initial increase, researchers posit that this could be due to a “celebratory response to legalization.” Similarly, traffic fatalities increases on April 20, commonly referred to as 4/20, as marijuana use increases. Also, legalization could attract new users who lack the experience and tolerance with marijuana.

However, once the party dies down, the research suggests that not only do traffic deaths begin to stabilize to levels before legalization, but there is actually a slight reduction. Results show that the initial increase lasted about a year before going down.

Despite legalization at the state level, it is still illegal for commercial drivers to consume marijuana, regardless of their state of residence.

Tyson Fisher joined Land Line Magazine in March 2014. An award-winning journalist and tireless researcher, his news reports, features and blogs bring depth to our editorial content, backed with solid detail. Tyson is a lifelong Kansas Citian.