A new study shows that fewer traffic deaths occur in states where medical marijuana is legal, than those without – especially among younger drivers. The study was conducted by researchers at Columbia University’s Mailman School of Public Health, and published in the National Journal of Public Health.
Their findings show that there is an 11 percent reduction in traffic fatalities, on average, in areas where medical marijuana laws are enacted. The study included a look at 23 states and the District of Columbia.
For those 45 and older, there was little evidence of reductions in traffic fatality rates. However, this age group is disproportionately represented in larger numbers amongst those enrolled in medical marijuana programs on the state level and that needs to be considered accordingly with the study’s findings.
But the most interesting statistic from the study by far is that the 15 to 44 age group of drivers had the largest reduction in traffic fatality rates in states where medical marijuana laws are in place.
The study also found that the presence of medical marijuana dispensaries correlated with fewer traffic fatalities. The study’s senior officer, Silvia Martins, a physician and associate professor, released a written statement that delved into the results further and shared her insights.
According to the written statement released by Martins,
“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.”
She also went to state what other factors could partially account for the correlation such as “strength of public health laws related to driving, infrastructure characteristics, or the quality of health care systems.”
She further postulates that these lowered rates of traffic fatalities may be occurring in these states as a possible relation to lower levels of alcohol-impaired driving. In fact, it seems as though younger people are foregoing alcohol for marijuana, which might be a factor for these lowered rates. States with medical marijuana laws have seen a shift away from alcoholic beverages, and that could be a mitigating factor for a decrease in traffic fatalities.
However, the researchers also made sure to caution that these lowered rates were not consistent among all states that have medical marijuana laws in place. States such as California and New Mexico, for example, showed reductions in traffic fatality rates initially but then tapered back into average rates. Both states saw a respective initial reduction of 16 percent and 17.5 percent but saw a gradual increase after.
Researchers undertook this study due to increased focus on public safety in states where medical marijuana laws are in place. Considering that nine states have already passed medical marijuana laws between 2010 and 2014, with more states introducing similar measures, there will likely be a considerable increase on cannabis as it relates to public health and safety.
Previous studies conducted have found that cannabis might be linked to drivers weaving in traffic more, and having slower reaction times comparatively. Other studies have also found that drivers under the influence of cannabis may also linked to reduced speed and increased headways. This suggests that perhaps cannabis users are more aware of related impairment and try to compensate accordingly.
Quick facts about the study
Published online in the American Journal of Public Health
Analyzed traffic fatality data from the National Highway Traffic Safety Administration (NHSTA) from 1985 to 2014
Factors taken into account while conducting this study included: laws in place on graduating drivers licensing, bans on using cell phones and texting while driving, enforcing the usage of seat belts as well increasing speed limit to 70 mph or more.
Other factors such as median household income and unemployment rates were also considered.
This post was originally published on April 9, 2017, it was updated on October 5, 2017.