Study: Marijuana or Alcohol, Which Causes More Fatal Automobile Accidents?

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Results from a French study published Wednesday indicate drivers under the influence of alcohol are decidedly more likely to be involved in a fatal car accident than marijuana users.  

The recent PLOS One study found motorists in France under the influence of marijuana increase their probability of causing a fatal car accident by 1.65 times – while “drivers under the influence of alcohol are 17.8 times more likely to be responsible for a fatal accident.”

The study examined the specific correlation between fatal car accidents and driving under the influence of alcohol and marijuana. Additionally, the researchers examined the role amphetamines, cocaine, and opiates played in France’s traffic fatalities.

For the study, Jean-Louis Martin analyzed fatal car accidents occurring in Metropolitan France during 2011 and compared them to a similar study conducted between 2001 and 2003. By scrutinizing the toxicology of 4,059 deceased drivers for “300 characteristics,” the study assessed the tests for “positivity and potential confirmation through blood analysis.”

marijuana vs alcohol study

Source: Voiesur 2011 data

“The proportion of persons driving under the influence of alcohol is estimated at 2.1% (95% CI: 1.4–2.8) and under the influence of cannabis at 3.4% (2.9%-3.9%). Drivers under the influence of alcohol are 17.8 times (12.1–26.1) more likely to be responsible for a fatal accident, and the proportion of fatal accidents which would be prevented if no drivers ever exceeded the legal limit for alcohol is estimated at 27.7% (26.0%-29.4%). Drivers under the influence of cannabis multiply their risk of being responsible for causing a fatal accident by 1.65 (1.16–2.34), and the proportion of fatal accidents which would be prevented if no drivers ever drove under the influence of cannabis is estimated at 4.2% (3.7%-4.8%).”

Statistically significant, the French research coincides with a 2015 report prepared by the National Highway Traffic Safety Administration (NHTSA). Per the NHTSA’s Fatality Analysis Reporting System, their cited research indicated “the increased risk of crash involvement for drivers using marijuana was 1.83 times that of drug-free drivers.”

The French study concluded, “Alcohol remains the main problem in France.” While the study discovered the overall number of traffic fatalities declined during the researched period, it also notes “that one in two drivers considered to be under the influence of cannabis was also under the influence of alcohol.”

Be safe, drive sober.

Photo courtesy of Kevin Schraer

About Author

Born in Long Beach, raised on the central coast: I surf, dab, burn, and blog – though not necessarily in that order. I'm a husband, a father and a lifelong consumer of connoisseur grade weed. I don't drink alcohol or consume any other "drugs." I consider myself to be living proof that weed is not a gateway drug. If it were, I'd be in some serious trouble. Instead, as a 50-year-old ex-realtor that has been smoking weed for nearly 80% of my life (just did the math) ... I can only say, marijuana is safer than prescription pills or alcohol could ever hope to be for calming what stirs the savage beast.

4 Comments

  1. No, that’s not an accurate way to state the results.

    A 1.65 adjusted odds ratio doesn’t mean someone is “1.65 percent” more likely, but rather 1.65 times more likely to cause an accident.

    • That is a very good assessment Russ of the given information. There is a lot of missing info on this study or the author of this article is purposely leaving out pertinent information. The comparison chart used isn’t complete and is missing needed research info to make a conclusive assessment. Plus the study was conducted nearly 15 years ago. Not sure what the author is trying to convey other than more people that drink and drive have a high instance of having a fatal car accident. Either way if you under the influence of a mind altering drug you should not be on the road!! Enjoy your cannabis but do it responsibly and don’t drive while high. Same said for alcohol or any other mind/body altering drug. Cannabis doesn’t need a bad rap due to idiots not being responsible!

  2. This points out how complicated the collection and interpretation of data can be.
    Looking at US data out of Washington state that was collected before, during and after legal marijuana use.
    They found that a driver in a fatal crash testing positive for active marijuana alone (acute use within a few hours, not night before, day before or week before), no other drugs or alcohol, was five times more likely to have killed someone other than themselves compared to a driver positive for alcohol alone. The drivers using marijuana actually killed more pedestrians, bicyclists, passengers or other drivers over the entire period than those using alcohol. While the overall deaths were greater for alcohol, this is because a driver positive for alcohol killed themselves, where the driver using marijuana survived the crash. A driver surviving the crash can refuse to provide blood samples. This may account for the data indicating that for overall THC, active and inactive, the drivers positive for marijuana were eight times more likely to have killed someone other than themselves compared to a driver positive for marijuana.
    Page 49 http://wtsc.wa.gov/wp-content/uploads/dlm_uploads/2015/10/Driver-Toxicology-Testing-and-the-Involvement-of-Marijuana-in-Fatal-Crashes_REVFeb2016.pdf
    Marijuana is not “safer”, but definitely different than alcohol.

  3. Overall the stats are just meaningless. doesn’t matter whether the driver DIES or not – that has nothing to do with their overall impairment. I agree 100% with Jim’s statement, “Either way if you under the influence of a mind altering drug you should not be on the road!! Enjoy your cannabis but do it responsibly and don’t drive while high. Same said for alcohol or any other mind/body altering drug. Cannabis doesn’t need a bad rap due to idiots not being responsible!”
    Really, don’t mess around and give legislators an excuse to avoid legalization OR to repeal legalization laws. Don’t mess it up for the rest of us.
    FYI, I think those under the influence of weed or just less likely to be driving… because they aren’t as likely to be in bar that closes, etc. and I’m much more likely to invite a stoned guest to stay until sober – don’t like drunks.

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