Legalized cannabis and recreational marijuana aren’t associated with an increase in traffic fatalities, new data shows. According to a new study from Kansas State University, cannabis reform hasn’t had the negative impact on road safety that previous research has claimed.
Lead researcher Andrew Young examined data on average traffic fatalities over a period of 23 years. He used two models to assess the impact of cannabis reform on traffic accidents including regression analysis and a difference-in-difference model.
Regression analysis is a statistical method that lets you examine the relationship between two or more variables and how they influence each other. The difference-in-difference model is considered a controlled before-and-after study.
Young first conducted a regression analysis on the traffic accident data, which showed no evidence that state legalization efforts had caused an increase or decrease in traffic fatalities.
After conducting the regression analysis, Young used a difference-in-difference model. He compared the traffic fatality rates in legal cannabis states and control states over the course of eight years starting five years before the states had legalized marijuana. There were no concrete trends found in the analysis.
Arizona, where medical cannabis is legal, the average number of traffic fatalities were similar to those in South Dakota and Wyoming where cannabis is prohibited in all forms. And although the traffic fatality rate was higher in Colorado in 2001 compared to Georgia and Iowa, the trend leveled out by 2003.
The number of traffic fatalities also dropped in Washington, D.C. after the City Council approved medical cannabis in 2010. The district’s car accident ratings were lower than in Utah or Virginia, which both prohibit cannabis and marijuana at the time. Utah voters later approved of medical cannabis in November 2018.
“Legalizing marijuana is not found to be a statistically significant predictor of fatality rates,” said Young. “This finding means that the legalization of marijuana for both medical and recreational purposes is not associated with either a reduction or increase in fatalities per 100,000 vehicle miles traveled.”
In 2016, there were up to 8 million diesel passenger vehicles in the U.S. and there are currently 500,000 refrigerated trailers in operation. Unfortunately, every year, there are approximately 6 million car accidents on U.S. roads.
There are actually more people injured in car accidents (3 million) than there are home burglaries reported every year (2 million). Previous research has attributed these accidents to marijuana and cannabis legalization.
In fact, almost a third of all highway fatalities are related to poor road conditions, obsolete road designs, or roadside hazards.
In 2018, the Insurance Institute for Highway Safety and the Highway Loss Data Institute reported that the frequency of collision claims were higher in four U.S. states where medical cannabis and recreational marijuana are legal. However, Young says these accidents aren’t related to the states’ legalization of marijuana.
“The results of the analysis suggest that there is no statistical relationship between marijuana legalization and fatal crashes,” said Young. “These findings suggest that concerns of policymakers and the public that legalizing marijuana will worsen road safety are not entirely founded.”
However, Young does note that the study is limited to states where medical cannabis has been legalized for adult use. There’s a chance that teenage drivers, under the influence of recreational marijuana, may be at an increased risk of car accidents.
That said, it’s illegal to drive under the influence of marijuana and medical cannabis. But the legalization of marijuana is not found to be a predictor of traffic fatalities.