Study: Passage of Medical Marijuana Laws Associated With Reduced Incidences of Alcohol-Related Traffic Fatalities

  • by Paul Armentano, NORML Deputy Director August 13, 2013

    The passage of medical cannabis laws is associated with a reduction in the public’s consumption of alcohol and with fewer incidences of alcohol-related traffic fatalities, according to data published in the Journal of Law and Economics.

    Investigators at Montana State University, the University of Oregon, and the University of Colorado assessed data regarding both alcohol consumption and traffic fatality rates for the years 1990 to 2010.

    Authors wrote: “Using individual-level data from the Behavioral Risk Factor Surveillance System (BRFSS) …, we find that MMLs (medical marijuana laws) are associated with decreases in the probability of [an individual] having consumed alcohol in the past month, binge drinking, and the number of drinks consumed.”

    Researchers further acknowledged that this general decline in the public’s use of alcohol was likely responsible for a parallel decline in the number of alcohol-related traffic fatalities.

    They wrote:

    “Using data from FARS (federal Fatality Analysis Reporting System) for the period 1990–2010, we find that traffic fatalities fall by 8–11 percent the first full year after legalization. … Why does legalizing medical marijuana reduce traffic fatalities? Alcohol consumption appears to play a key role. The legalization of medical marijuana is associated with a 7.2 percent decrease in traffic fatalities in which there was no reported alcohol involvement, but this estimate is not statistically significant at conventional levels. In comparison, the legalization of medical marijuana is associated with a 13.2 percent decrease in fatalities in which at least one driver involved had a positive BAC level. The negative relationship between the legalization of medical marijuana and traffic fatalities involving alcohol lends support to the hypothesis that marijuana and alcohol are substitutes.”

    Authors determined, “We conclude that alcohol is the likely mechanism through which the legalization of medical marijuana reduces traffic fatalities. However, this conclusion does not necessarily imply that driving under the influence of marijuana is safer than driving under the influence of alcohol. Alcohol is often consumed in restaurants and bars, while many states prohibit the use of medical marijuana in public. If marijuana consumption typically takes place at home or other private locations, then legalization could reduce traffic fatalities simply because marijuana users are less likely to drive while impaired.”

    The abstract of the study, “Medical marijuana laws, traffic fatalities, and alcohol consumption,” is available free online here. NORML has several additional papers specific to the issue of cannabis and psychomotor performance available online here.

    28 responses to “Study: Passage of Medical Marijuana Laws Associated With Reduced Incidences of Alcohol-Related Traffic Fatalities”

    1. Differ says:

      Causation =\= correlation, but the study still can’t hurt.

    2. John Bradley says:

      So why is Marijuana illegal? Why isn’t there driving tests to test how well a driver drives while on the influence of Marijuana like they did with alcohol in the 70’s?

    3. fumester says:

      As more states pass MMJ laws, there should be an associated decrease in alcohol usage/deaths. The same should also hold true for opioid painkillers. Big Booze and Pharma know this hence their traditional resistance to marijuana decrim/legalization. Read the tea leaves, alcohol will finally become known as one of the most harmful drugs humans consume and I daresay the decline in tobacco use will speed up exponentially as well.

    4. St. Nick and Dime says:

      Well Im not surprised. The ones that will lose the most are big tobacco and alcohol. And I have just one thing to say about that: Ha ha ha ha! Those drugs suck.

    5. Galileo Galilei says:

      I used to play music in red neck bars all those years ago. A guy walks out of a bar. He’s been drinking all evening. Now HE decides if he’s in good enough shape to drive.

      What’s wrong with this picture?

    6. Dana Edmonds says:

      Paul you are my hero!

    7. Demonhype says:

      Okay, maybe I was wrong about alcohol companies needing to worry then. I still can’t imagine that alcohol is going to go away just because of marijuana, but I guess perhaps it does get consumed less.

      I’m not convinced that legalizing is going to result in an uptick of people getting into MJ-related accidents. I’ve heard it said that someone driving under MJ influence is more likely to go way too slowly rather than drive fast, unlike with alcohol, so you’re still probably more likely to maintain a low level of high-fatality accidents even if people started driving high. Of course, that’s just word-on-the-street and not scientific evidence.

      Of course, for my own part, I can’t imagine that more people are going to be driving high just because smoking pot is legal. First of all, if people are lucid enough to avoid driving high because pot is illegal, then it can’t possibly be impairing them enough to be unable to make the right decision. Second of all, people who drive under the influence of alcohol don’t do it “just because” alcohol is legal–after all, driving drunk is illegal and so would driving high if MJ gets legalized. So they’re either driving drunk because liquor impairs you to a point where you can’t make the wise decision to not drive while drunk–which we’d already have with MJ if it impairs people in the same way–or you have some idiots who underestimate their own capacity for impairment–which again, we’d still have whether MJ is illegal or not. All this talk about “what about traffic safety, if we legalize everyone will be high ALL THE TIME, even on the road or working with heavy machinery WONT’ SOMEONE THINK OF THE CHILDREN!” is just more irrelevant extinction-burst from the panic-stricken Drug War profiteers sensing their free ride is at an end. I have no sympathy whatsoever.


    8. phrtao says:

      In this age of ‘legal highs’ and ever changing pharmacology of illegal drugs we need to move to impairment testing – not chemical testing to decide it you are DUI. There is some evidence that people (especially the young) are using any kind of drug they can get their hands on so long as it does not show up on the testing they are subjected to. Drug testing should deter the use of dangerous drugs not push people to dangerous drugs simply because people will not test positive after taking them. As we all know the cannabis tests are the most stringent since they can detect use within the last 28 days but you would still be classed the same as someone under the influence if you tested positive.
      The law on drugs and the testing is no longer fit for purpose and is increasingly detached from the realities of drug use today.

    9. Miles says:

      This study makes perfect sense to me. As someone who uses cannabis and alcohol, often in combination, I can tell you that I drink much less because of the combination. As a result, I’m not drunk when I get ready to drive and I’ve never had a single accident after almost 40 years of cannabis use!

      Also, from my personal experience, I’ve driven many times under the influence of marijuana and have never had the slightest problem. It is simply a matter of being responsible; which I believe the majority of cannabis users are.

    10. Ben says:

      This doesn’t exactly fit in with this article-
      but, it signals the potential for one of the very largest dominoes to fall…