By on June 17, 2021

It’s always nice to get a break from the endless stream of industry marketing materials about electrification, though this week’s impromptu theme still involves going green. Following news that General Motors is considering changing its drug testing policies to exclude marijuana, there has been heavy coverage of an Insurance Institute for Highway Safety (IIHS) study claiming states that have legalized recreational use of cannabis are seeing more crashes.

But the framing seems wildly irresponsible as it fails to highlight the problem being heavily tied to individuals operating a vehicle under the influence of marijuana and alcohol combined. It’s more or less what the IIHS attempted to do in 2018 with help from the Highway Loss Data Institute (HLDI). Our guess is that the duo is seeking out fresh reasons for insurance companies to raise rates in regions that have legalized pot because even their own research complicates the issue. 

Their latest data suggests that legalization and retail sales of cannabis in California, Colorado, Nevada, Oregon, and Washington resulted in a 6 percent increase in injury crash rates and a 4 percent increase in fatal crash rates compared with other Western states where pot was illegal at the time of the study. The IIHS and HLDI have actually conducted a series of studies since 2014, with the outcome often the same. But it’s at odds with a study released by the National Highway Traffic Safety Administration in 2015, which came to the conclusion that THC wasn’t contributing to an increase in accidents.

Independent tests and surveys have been a mixed bag. The majority seem to agree that cannabis consumption typically slows driver reaction times and makes it harder to focus. But regular users don’t tend to suffer from these side effects and the abundance of caution THC hilariously might make some stoners better drivers. Simulations have likewise shown them to be less likely to speed or act aggressively in traffic and they typically increase following distances (something the IIHS noted). There are even instances where testing has shown subjects declining to get behind a wheel in a real-world setting, after stating they didn’t feel comfortable driving high.

There’s been no consensus on whether or not smoking pot makes you a menace behind the wheel but the early data seems to suggest not. So then why are the IIHS and HLDI claiming otherwise? Because they can incorporate alcohol on the sly.

In fact, the latest from those outlets used data collected from injured drivers visiting emergency rooms in Sacramento, California; Denver, Colorado; and Portland, Oregon — none of which represented an increased risk associated with marijuana unless it was combined with booze. Of the 1,200 people examined, none of the drivers that tested positive for smoking weed were injured at a higher rate than those who were sober. But the ones that were drinking and also decided to puff the magic dragon did see elevated numbers.

This isn’t a recommendation to get stoned and hop into a vehicle. We wouldn’t advise using any mind-altering substance to someone preparing to drive an automobile and being sober offers some pretty clear tactical advantages. However, the framing of these studies is often misleading and unhelpful in terms of deciding future legislation in a truly effective manner.

If you’re hoping for an outlet that actually seems interested in getting to the bottom of things without a lot of spin, the American Automobile Association (AAA) has frequently shown itself capable of nuance. It’s looked into the issue to and decided that the most serious issue is likely people partying themselves into oblivion using a variety of substances. The AAA Foundation’s annual Traffic Safety Culture Index found that drivers who use both marijuana and alcohol “were significantly more prone to driving under the influence of alcohol alone versus those who only drink alcohol but do not use marijuana.

The outlet also made it clear that it does not support the “legalization of recreational marijuana because of its inherent traffic safety risks and the difficulties in writing legislation that protects the public and treats drivers fairly.” It apparently just sees boozing as the bigger issue and full-on partying behind the wheel as the worst-case scenario for motorists. It’s an interesting report and well worth reading for the added context and rather clear statistical information.

But that doesn’t make the IIHS content totally worthless. Despite our criticizing the group for framing the issue in a specific manner, those who bother to read the entirety of their article still end up learning that alcohol plays a significant factor. It even references the above AAA report and eventually suggests that disparities in state and local regulations might be influencing driver behaviors and the tabulated data. We’re just annoyed that it makes these sweeping assertions using somewhat specious reasoning and limited information. No study appears to have a handle on exactly how much cannabis consumption impairs motorists and most of the data we’ve seen seems to indicate it varies wildly from person to person. Knowing that simply has not stopped the IIHS from jumping to conclusions.

“Our latest research makes it clear that legalizing marijuana for recreational use does increase overall crash rates,” IIHS-HLDI President David Harkey said in a statement. “That’s obviously something policymakers and safety professionals will need to address as more states move to liberalize their laws — even if the way marijuana affects crash risk for individual drivers remains uncertain.”

Policymakers and safety professionals have been placed on notice. Even though there are still glaring questions surrounding the matter, it’s time for them to address these issues as the scourge of hypothetical dope fiends revving their engines in a fit of refer madness is upon us.

[Image: Mitch M/Shutterstock]

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48 Comments on “IIHS Claims Marijuana Legalization Causes Crashes...”


  • avatar
    tomLU86

    Yes! I don’t see marijuana use DROPPING as it becomes legal.

    It will probably rise. Hence, more drivers probably will be impaired to some degree by pot, hence accident rates may rise.

    All the more reason to bring on the AV, to make our world safer…

    Until then, it will give the government, state and federal, all kind of reason for even more onerous rules and restrictions.

    What a dismal future for those of us who enjoyed being MOTORISTS in cars that required driver involvement and rewarded good driving skill with a very satisfying experience behind the wheel.

    Can TTAC’s super sharp writers inform us as to WTF is going on in Chicago with speed/red-light cameras please?

    I think that is of more import, and more value, at least to me.

    • 0 avatar
      Lou_BC

      @1tomLU86 – in Canada there hasn’t been a marked increase in cannabis consumption post legalization.

      The conclusion is flawed since it looks at alcohol with cannabis. The only conclusion is the obvious one. When you combine 2 substances that are known to impair driving, there is a synergistic response. Only those searching for validation would say that cannabis is therefore worse.

    • 0 avatar
      Matt Posky

      I have been reading about the rule change that resulted in a slew of new tickets being launched. Expect an article in the days to come.

  • avatar
    SCE to AUX

    It’s unquestionable that youth, alcohol, sleep deprivation, and distractions make people worse drivers.

    It’s arguable that AutoPilot and other driving aids makes people worse drivers.

    MJ? I don’t know, and have no personal experience, but it doesn’t seem like a good idea. However, 4-6% increases are small enough that I question whether the study decoupled all other variables, such as the alcohol component that was mentioned.

  • avatar
    Jeff S

    Driving has gone to pot.

  • avatar
    FreedMike

    IIHS is high. No way they’re correct about this.

  • avatar
    DenverMike

    They keep referring to “crash rates”, crash risk, etc, without explaining the numbers.

    If that’s per driven mile, it means very little. If not, it means even less.

  • avatar
    EBFlex

    Wait so a mind altering substance affects peoples ability to operate a vehicle???

    Soon TTAC will be posting stories that claim water is wet and ice cream is cold.

  • avatar
    redapple

    FREED

    Haven’t I read that the group in their 20-35s are drinking a good deal less alcohol?

    Maybe it balances out in total.

  • avatar
    Tele Vision

    Last I remember most crashes happen in parking lots. No fatalities but plenty of insurance claims. Is that factored in?

    “Oh, people can come up with statistics to prove anything, Kent. Forty percent of all people know that.” – Homer Simpson

  • avatar

    Marijuana, also known as weed, herb, pot, grass, bud, ganja, Mary Jane, and a vast number of other slang terms is inherently good. Only alcohol consumptions and smoking cigarettes can cause car crashes and cancer. Marihuana is just mind-altering substance and our minds are so messed up that we desperately need to alter our minds to be able to live happy long lives in coming bright future.

  • avatar
    dal20402

    Pot driving is far from ideal, because it gives slow reflexes, but at least it doesn’t give false bravado and horrible judgment. I think I’d rather have 10 weedy drivers than one drunk driver. Of course, this is really about pot and alcohol combined, but we still suffer from extreme reefer madness in the US, so the IIHS and the press focus on the pot.

  • avatar
    DenverMike

    Dear IIHS,

    Eat a d!ck. You can only DREAM of a world where you’re mostly dealing with stoned drivers, vs on alcohol and everything else, but including sober and distracted, multitasking, etc.

    It could be argued, weed is our friend. But as long as Americans are combining Alcohol use with something else, what would you prefer? Meth? coke?

    Please go crash (test) some cars and shut up.

    • 0 avatar
      Oberkanone

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    • 0 avatar
      Oberkanone

      Rules of Conduct

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      Is not consistent with the permissible uses outlined by the Terms of Service, including, but not limited to, content that is unlawful, harmful, threatening, abusive, harassing, defamatory, libelous, invasive of another’s privacy, vulgar, profane, sexually explicit, obscene, racially or ethnically offensive or otherwise objectionable;

  • avatar
    wolfwagen

    NO Shit

    In other news water is wet, healthy grass is green.

    It doesn’t matter what their study said The DOT (FMCSA) has had regulations regarding alcohol and drug use (Marijuana. Cocaine. Opiates, Amphetamines and methamphetamines, Phencyclidine – PCP) for decades – for a reason.

  • avatar
    Pig_Iron

    Prohibition doesn’t work. It doesn’t work with alcohol. It doesn’t work with cannabis. It doesn’t work with arms. If someone gets hit they will invoke the organic and natural right to self-defense. Whether it’s bare fists or MIRV tipped ICBMs . . . . Oh wait, I thought I was at TTAG for a minute. Ooopsey.
    ;-)

    • 0 avatar
      SCE to AUX

      This isn’t a debate about substance prohibition; the question is about selective prohibition under certain circumstances.

      Rights are rarely – if ever – unabridged.

      For example, the right to free speech doesn’t include libel or slander. The right to free assembly doesn’t extend into a disaster area cordoned off for public safety. And – in this case – the right to use recreational mild-altering drugs – shouldn’t extend to their influence while operating equipment.

    • 0 avatar
      Lou_BC

      I do agree that prohibition doesn’t work but some restrictions do provide a net benefit.
      One can drink if “of age” but not drive impaired or get into drunken brawls. Cannabis should be no different.
      I don’t have a problem with anyone owning a firearm if you are compos mentis, and can demonstrate the safe use and provide secure storage.

  • avatar
    Yankee

    If anything, I would think the data rates would be skewed drastically downward due to there being no reliable, roadside-administered test law enforcement can use to determine whether someone is high at the time of an accident, unlike alcohol inebriation. I wish legalization would have waited until there is a way to test for present impairment, not recent or past use, which is all we have. Someone can crash into you and be high as a kite but there is no way to hold them accountable because law enforcement has no tools to prove it, unlike the proof that you were just hit by a drunk driver. This, to me, is the real problem. People should be free to do what they want, as long as they are capable of being held accountable when their actions harm others.

    • 0 avatar
      Lou_BC

      I do agree that sound metrics should have been in place prior to legalization. Unfortunately there is too much potential for misuse/abuse when one uses standard impairment/reflex tests.

  • avatar
    Crosley

    Marijuana proponents are always incredibly dishonest that “their” drug is some magic health food and that its never hurt anyone.

    At least people that drink alcohol and smoke tobacco don’t try to pretend there aren’t consequences.

    Of course more people getting high and getting behind the wheel is going to cause car accidents, it’s common sense.

    • 0 avatar
      JD-Shifty

      Alcohol is much worse and we’ve been lied to about how dangerous it for hundreds of years.

    • 0 avatar
      Lou_BC

      @Crosley – cannabis does provide a benefit with some people in relation to nausea, appetite, and pain control. Alcohol does not have such benefits.

      Some ethnicities do not do well with alcohol because alcohol wasn’t a part of their culture. Those of us from European and Middle-Eastern descent have an inherited greater tolerance because weak alcoholic beverages were the fluid of choice because it was safer than water to drink.

      Current alcoholic drinks have much more alcohol in it than what our ancestors drank. Alcohol is a much greater drain on society than other drugs.

      Cigarettes are carcinogenic and that has been a known for probably a century.

      There has been an increase in cannabis consumption since legalization but the question is whether or not people were accurately reporting their usage when it was illegal.

      • 0 avatar
        golden2husky

        Lou, you nailed it. I certainly don’t condone driving under the influence of drugs, and yes Alcohol is most certainly a drug. I get into these discussions at work and the amount of anti-pot sentiment runs pretty high, no pun intended. Yet all those people drink and that’s fine but pot is not. Pretty hypocritical to me. That’s one of the many reasons I oppose drug testing at work. Even the lushes get a pass, but the guy who came back from Colorado a week ago gets fired. So, unless there is a fair standard, there should be no testing in most instances. Employers already have too much input into your life – its a job, and what you do at home is none of their damn business.

        • 0 avatar
          Lou_BC

          @golden2husky – in Canada police forces have policies stating that “one must be fit for duty”. I’ve read that some police forces have a rule of no cannabis for 24 hours prior to a shift with the RCMP being at the extreme opposite end with 28 days cannabis free. The military leaves it at “must be fit for duty”.
          Our laws protect workers rights because the courts ruled that typical drug tests only show the presence of a drug not the degree of impairment. Alcohol is the only drug with a clearly established correlation between BAC and impairment.

      • 0 avatar
        Crosley

        Alcohol has medicinal benefits (wine and your heart, etc) but I’m not going to pretend that’s why everyone needs to be drinking.

        Just admit you want to get baked instead of marijuana being some silly wonder drug.

        • 0 avatar
          Lou_BC

          Where have I said it was a wonder drug?

        • 0 avatar
          golden2husky

          Alcohol ok for the heart? There are plenty of studies showing alcohol consumption causes irreparable damage to the brain. I’m sure pot will end up having similar issues, though there are proven benefits for some – hence medical MJ dispensaries. The reality is putting substances into your body is likely, over the long haul, to be deleterious to your health. I just get annoyed listening to people jabber on about how “bad” pot is when they think nothing of drinking a couple of six packs a week,

        • 0 avatar
          DenverMike

          Pretending? Forget the medical benefits for a second. How about we don’t pretend the entire MJ prohibition wasn’t based entirely on lies?

          Oh you’re not pretending? OK maybe you should know your history. This why correction/progress is taking these many decades. Unless you have a dog in the fight, like beer/alcohol stocks, law enforcement, prison industry, narco trafficking, etc? Or is it just pure ignorance?

    • 0 avatar
      DenverMike

      Consequences? The pot related consequences aren’t even worth mentioning compared to alcohol and all other drug related consequences, driving related or not.

      But why dwell on the alcohol + pot, or meth + pot scenarios, as if by themselves they’re fine, while ignoring the pot *instead of those* scenarios, whether lives are saved or not.

      Never mind the consequences of maintaining insane pot prohibition policy, from incarceration, inside/outside the US, to body bags by the 100K, on both sides of the border.

      It’s Dark Ages sh!t.

      • 0 avatar
        golden2husky

        DenverMike:

        Good point about incarceration. I was on a jury a few years ago and the way the cops were able to make the traffic stop legit was by saying they smelled pot. Turns out the guy did have pot on him, but that ultimately was the least of his problems. After the case was over, the lawyers for both sides were waiting for us near the exit of the building. The prosecuting attorney flat out said that if pot was legal, getting “legit” stops was going to be much more difficult and the police would have much more difficulty making some of the stops and searches legal. So, yeah, weed has been used as legal gateway into a lot of other things…

  • avatar
    bachewy

    Sigh, again, another ‘study’ with not enough data. There is still no test that can prove impairment by marijuana after an accident. It’s a judgment call by the cops on the scene.

    So again they say, “well since pot is legal and wrecks went up, pot is causation’ without looking at other factors such as population increase (which results in more wrecks simply due to statistics per capita).

    Sure, one shouldn’t high and drive, but don’t penalize entire states just to get more $$$ when the majority of people in those states do not get high, even after legalization.

    • 0 avatar
      Lou_BC

      In Canada one study showed similar results. There was an increase in crashes where cannabis and alcohol were consumed together. Cannabis is subsequently being demonized. Ironically, the one study was cosponsored (i.e. funded) by “Beer Canada”, an association representing beer manufacturers. A lobby group for beer spits out a report indicating that cannabis is bad.. hmmmm….

  • avatar
    Jeff S

    Politicians use to promise a chicken in every pot now it is pot in every chicken.

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