Cannabis in America

Study: Medical Marijuana Laws Linked to Drops in Traffic Fatalities

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States with medical marijuana laws have fewer traffic fatalities than those without, especially among younger drivers, says a new study.

Researchers at Columbia University’s Mailman School of Public Health found on average an 11 percent reduction in traffic fatalities when examining places that have enacted medical-marijuana laws–in total, 28 states and the District of Columbia.

There was also a strong correlation between the presence of medical marijuana dispensaries and fewer traffic fatalities, claimed the study, which was published in the American Journal of Public Health.

The presence of medical marijuana laws seemed to have the biggest effect on the number of traffic fatalities for individuals between the ages of 15 and 44, with special emphasis on those aged 25 to 44 years.

Dr, Silvia Martins, a physician and associate professor who was a senior author of the study, told the Washington Post that the lower traffic fatality rates could be related to lower levels of alcohol-impaired driving as people–especially younger people–substitute weed for booze.

“We found evidence that states with the marijuana laws in place compared with those which did not, reported, on average, lower rates of drivers endorsing driving after having too many drinks,” Martins said in a written statement.

However, not every state experienced a substantial reduction in traffic fatalities. California and New Mexico, for example, both experienced gradual increases in traffic deaths after initial reductions of 16 percent and 17.5 percent, respectively.

“These findings provide evidence of the heterogeneity of medical marijuana laws and indicate the need for further research on the particularities of implementing the laws at the local level,” said Julian Santaella-Tenorio, a doctoral student in epidemiology at Columbia, and the study’s lead author. “It also indicates an interaction of medical marijuana laws with other aspects, such as stronger police enforcement, that may influence traffic fatality rates.”

While medical marijuana laws have seemingly influenced these rates, they may not be the sole factor driving the change.

According to Martins, other factors that might help explain the correlation could be the “strength of public health laws related to driving, infrastructure characteristics, or the quality of health care systems.”

Researchers used National Highway Traffic Safety Administration data on traffic fatalities from 1985 to 2014 to conduct the study. Factors such as whether the states had graduated driver licensing laws, as well as median household income, unemployment rates, laws increasing the speed limit to 70 mph or more, laws on enforcing the use of seat belts, and bans on using cellphones and texting while driving were all taken into account.

Alexis Evans
Alexis Evans is an Assistant Editor at Law Street and a Buckeye State native. She has a Bachelor’s Degree in Journalism and a minor in Business from Ohio University. Contact Alexis at



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