A good deal of time, money, and energy has been spent on the issue of drinking and driving. For all the hype surrounding medical marijuana these days, however, not only is anti-driving advocacy weak — data on the effects of marijuana and traffic deaths is sparse as well. CU Denver economics professor Daniel Rees and Montana State University assistant economics professor D. Mark Anderson hope to change that.
In a recently released study, the duo analyzed state-level data for correlations between medical marijuana laws and a variety of outcomes. An abstract details some of their more surprising findings:
Legalization of medical marijuana is associated with increased use of marijuana among adults, but not among minors. In addition, legalization is associated with a nearly 9 percent decrease in traffic fatalities, most likely to due to its impact on alcohol consumption. Our estimates provide strong evidence that marijuana and alcohol are substitutes.
The authors accounted for variables including seat-belt usage, miles driven, and changes in traffic laws, though don’t explicitly draw a 1-to-1 correlation between marijuana usage and decreased traffic fatalities. They further acknowledge “cannabis use impairs driving-related functions such as distance perception, reaction time, and hand-eye coordination,” though drivers “under the influence of marijuana reduce their velocity, avoid risky maneuvers, and increase their ‘following distances.'”
The report concludes that marijuana legalization is associated with a 12-percent drop in alcohol-related fatal crashes, and a 19-percent decrease in the fatality rate for people in their 20s. Despite the decrease in both rates, the study emphasizes it is not necessarily safer to drive under the influence of marijuana than alcohol — just that medical-marijuana usage alters the likelihood of driving.
According to the Denver Post, the study awaits a peer-review.