By on October 18, 2018

The Insurance Institute for Highway Safety and the Highway Loss Data Institute announced Thursday that auto crashes in states with legalized recreational marijuana have increased 6 percent. Both groups will be on hand at the Combating Alcohol-and Drug-Impaired Driving summit at IIHS’ Vehicle Research Center in Ruckersville, Virginia to present two studies on the issue. Perfect timing, considering Canada just became the second country to legalize the substance and support for decriminalization continues to grow in the United States.

Of course, things are rarely so simple. While the IIHS and HLDI remain confident in their research, the National Highway Traffic Safety Administration claimed marijuana use was unlikely to contribute to traffic mishaps in any meaningful way back in 2015. And that’s just for starters. There is so much conflicting information on this issue, it’ll make your head spin harder than the most savage bong rip of your life, bro. 

While there’s no reason to doubt the data from the IIHS, it could also be claimed that it’s in the organization’s best interests to find new ways to elevate insurance rates while simultaneously conducting meaningful crash test research. In this instance, analysts estimated that the frequency of collision claims per year rose a combined 6 percent following the start of legal sale of recreational marijuana in Colorado, Nevada, Oregon, and Washington versus the control states of Idaho, Montana, Utah and Wyoming. That data came via collision loss information collected between January 2012, when recreational sales began for Colorado and Washington, and October 2017.

A separate IIHS study examined police-reported crashes between 2012 and 2016, before and after retail sales began in Colorado, Oregon and Washington. The IIHS estimated the three states combined saw a 5.2 percent increase in the rate of crashes per million vehicle registrations, compared with neighboring states that did not legalize marijuana sales. However, it can’t accurately attribute this to marijuana, just that there is a correlation of some kind — which is important to remember while considering the data.

According to the National Safety Council, countrywide crash rates rose by 6 percent in 2016 and 7 percent in 2015. Framed this way, the pot-smoking states seems to be roughly on par with the national average. See how slippery statistics can be?

Let’s keep playing devil’s advocate and swap sides. Fatalities on U.S. roads fell slightly in 2017 after two years of sizable increases. But on-road deaths in Colorado continued to climb. In fact, 2017 was the worst year for the state since 2004… when it had a significantly smaller population and marijuana wasn’t legal. Swapped again!

We could do this all day. The issue might even come down to some of these state’s incredibly swift population growth. Still, IIHS analysts say they controlled for “differences in the rated driver population, insured vehicle fleet, the mix of urban vs. rural exposure, unemployment, weather and seasonality.” Maybe there is something to this, if they truly managed to nullify any margin of error.

Previous research efforts have strongly hinted that driving under the influence of marijuana is less debilitating than alcohol — not just because THC has less of an affect on fine motor skills, but also because those using it are statically less likely to feel confident in engaging in complex tasks or risk-taking behaviors. Typically, the inverse of this is true when it comes to booze. However, the consumption alcohol is more easily measured and the outward signs of impairment are usually more visible, while the amount of marijuana present in a person’s body doesn’t consistently relate to impairment.

Those earlier studies also indicated that regular pot smokers are less likely to have issues. Despite the demonstrable neurophysiologic impairments associated with THC, studies involving experienced smokers driving on an outdoor course have shown almost no functional impairment under the influence of marijuana — except when combined with alcohol. We covered those studies last year, some of which are highly intriguing, when the IIHS and HLDI claimed that collision frequencies in Colorado, Oregon and Washington were roughly 3 percent higher than what would have been expected without legalization.

This year sees the agencies taking a more serious run at the burning bush. “The new IIHS-HLDI research on marijuana and crashes indicates that legalizing marijuana for all uses is having a negative impact on the safety of our roads,” said IIHS-HLDI President David Harkey. “States exploring legalizing marijuana should consider this effect on highway safety.”

“Despite the difficulty of isolating the specific effects of marijuana impairment on crash risk, the evidence is growing that legalizing its use increases crashes.”

It should be said that driving under the influence of either alcohol or marijuana is totally against the law and not something we condone. Neither substance should be in your system when you take the wheel, regardless of their legal status. But the Insurance Institute for Highway Safety seems to be taking things a step further by subtly suggesting that states might want to think twice about decriminalizing recreational pot. Following that logic, it seems they’d probably want to push for the prohibition of alcohol as well.

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21 Comments on “Higher Risk: Study Claims States That Legalized Marijuana Have More Traffic Accidents...”

  • avatar

    “it’ll make your head spin harder than the most savage bong rip of your life, bro”
    Thanks for that. Matt

  • avatar

    “it’ll make your head spin harder than the most savage bong rip of your life, bro”
    Thanks for that, Matt

  • avatar

    The drivers in the control states were being super careful because they didn’t want to get stopped coming back from the pot states.

  • avatar

    I have never trusted the IIHS. A friend of mine is a columnoist for a Colorado newspaper and he stated DWI rates actually decreased after marijuana was legalized. This seems to be one of those “depends on who you ask” situations.

  • avatar

    Control states? Give me a break. The only apples to apples comparison is accidents per million miles driven. Did it statistically rise in the weed states?

  • avatar

    Relying on what should be known as the Insurance Institute for Higher Surcharges for any “research” (sic) on traffic safety or enforcement is foolish. The IIHS has such a severe conflict of interest in traffic enforcement that their publications are pretty much public relations and business profit support documents, not legitimate research.

  • avatar

    All of the control states abut legal states, and it’s not like there’s border security checks….

    They should have used somewhere like Texas or Louisiana that aren’t half an hour from a pot shop.

  • avatar
    87 Morgan

    This study or data from what i can tell has little to do with weed.

    Distracted driving is the reason wrecks and the severity of them is on the rise. As for CO the population explosion can account for any increase as seemingly every 4th car anymore has an out of state tag.

    Did one or two stoners get in a wreck? You bet! What cant be pinned down is whether that wreck would have occured with or without legal weed. It is not like weed was just introduced to the population….they just buy it in a less skeevy fashion now.

    • 0 avatar

      “It is not like weed was just introduced to the population….they just buy it in a less skeevy fashion now.”


    • 0 avatar

      re: Distracted driving

      This is the real problem, as opposed to just pinning it all on the potheads. I think I’d rather take my chances with a slightly-baked but still focused stoner than some fully sober slack-jawed moron who is typing on his phone while sucking on a chili-dog as he pilots his bass-pounding WRX through the town square during Friday night happy hour.

  • avatar

    Legal weed.

    And you thought computers made people stupid and lazy.

  • avatar

    There are accidents and then there are accidents. A few decades back, I read that Massachusetts had the country’s highest accident rate but one of the lowest traffic death rates.

  • avatar

    The insurance industry has to be already feeling the pinch of less alcohol related DWI/DUIs. They won’t get to jack up the rates of too many, not convicted of such.

    2X the pay usually for perps without them truly being a menace driving. The really dangerous alcoholics don’t usually have insurance (or license) anyway, after their 3rd or whatever drunk driving conviction.

  • avatar

    I’m sure this is possible, but I don’t trust their research. Screw the comparisons – just look at the raw data from years before and after legalization. Even then, they still need to provide correlation and causation, and I’ll bet they can’t do that.

  • avatar

    It makes sense that drug-related incidents are on the rise. Not just from weed, although that likely is a big contributor, but from the more widespread use of other drugs as well. It is a growing and real problem in society as a whole, not just on the roads.

  • avatar

    Increasing accessibility, and therefore usage, to a psychotropic drug increases accidents? Anyone really surprised?

  • avatar

    Real men get plastered – right?

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