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Transportation Government

Federal Study: Marijuana Use Doesn't Increase Auto Crash Rates 328

Posted by Soulskill from the but-still-don't-do-it dept.
An anonymous reader writes: After the legalization of marijuana in multiple states around the U.S., many are worried about a corresponding uptick in car crashes as people drive while under the influence of pot. But according to a new federal study (PDF) commissioned by the National Highway Traffic Safety Administration, those fears seem unfounded. They report that after adjusting for other factors (people who tend to drive after using marijuana also tend to be more crash-prone in general), there was no statistically significant increase in crash rates by drivers who tested positive for the drug. It's still a bad idea to drive high, but driving drunk is far, far worse: "One substance was shown to have a major influence on crashes: alcohol. The study confirmed the enormous danger of drinking and driving, even after age and sex adjustment: drivers with a 0.05% blood-alcohol level were found to be twice as likely to be in a crash. For a person weighing 180 to 190 pounds, that could be a single can of beer, glass of wine, or shot of liquor. At 0.08% (two drinks), the likelihood is quadrupled, and at .20% (four drinks or more), the risk is higher by 23 times."
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Federal Study: Marijuana Use Doesn't Increase Auto Crash Rates More

Federal Study: Marijuana Use Doesn't Increase Auto Crash Rates

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  • But, but, you're using logic and science (Score:5, Insightful)

    by msobkow ( 48369 ) on Tuesday February 17, 2015 @09:15AM (#49072907) Homepage Journal

    The problem is you're using logic and science to argue with people who still believe bullshit WOD propaganda like the "gateway drug" theory.

    They're not interested in facts, statistics, or scientific evidence. Like fundamentalist religion people, they've made up their mind and anything that disagrees with their predisposition is a "lie".

    • Re:But, but, you're using logic and science (Score:5, Funny)

      by Rockoon ( 1252108 ) on Tuesday February 17, 2015 @09:31AM (#49072981)
      Drunk drivers run through stop signs.
      High drivers wait for the stop signs to turn green.

      • Not a surprise to potheads (Score:2, Insightful)

        by Anonymous Coward

        None of this is a surprise to potheads. Being stoned in the driver's seat makes you MORE cautious and attentive to everything outside the vehicle, not less. It's the exact opposite of being drunk in the driver's seat.

    • Re:But, but, you're using logic and science (Score:5, Insightful)

      by gstoddart ( 321705 ) on Tuesday February 17, 2015 @09:53AM (#49073125) Homepage

      You mean like how they call it a narcotic, and a hallucinogen, when in fact it is neither?

      As you say, they're not interested in facts ... they've re-defined the terms to meed an ideological view, and it has nothing at all to do with the truth, just what they want the message to be.

      The vilification of marijuana is so engrained in the way these people see the problem they're long past the point where they can discuss it in terms of reality.

      Make no mistake about it, these people have built up a fantasy in their heads, and anybody who tries to demonstrate otherwise is "teh evul enemy". There really is no room for science and facts in this debate for some of the idiots involved.

      • I vilify Marijuana because it smells really awful.

        So long as you smoke it where that scent doesn't regularly affect your neighbors, though, let's just look at studies--like this one--to decide whether and where it's acceptable to use.

        My $0.02

    • Like fundamentalist religion people, they've made up their mind and anything that disagrees with their predisposition is a "lie".

      And, conversely, most of these kind of studies are funded or supported by marijuana supporters--and so they often end up toeing the line that marijuana intoxication is somehow not as bad as other forms of intoxication when it comes to matters like driving. This whole study was the equivalent of my old stoner roommate's "I drive better when I'm high" line. Only he didn't. He drove much worse when he was stoned. He was just too fucking stoned to realize it.

      Look, I've got nothing against marijuana. Toke away.

      • Looking at the study, it is not clear that they accounted for level of THC. It appears that a driver with any level of THC is counted. If that is the case, a large number of drivers with only a hint of THC as compared to a smaller number with high levels could impact the results. Maybe I just missed it, but it seems like a critical factor to address.
        • If you are correct about that, then there would be a lot more weekend-smokers on the road during the week, who have THC in their bloodstream but haven't smoked in days and are in no way high. That would mean that many counted as THC-involved accidents would have involved *completely sober* people, indicating that the results were skewed such that it appears that sober and high drivers have roughly the same incidence of accident when the reality would be that sober drivers are actually more likely to be in a
          • Your logic does not hold. The entire basis what that those with THC exhibited only a slightly higher rate than the control group. If the population of very low THC cases is great enough, then any other difference could easily be masked within the margin of error.

            But, I think even you would not argue that it stands to reason that if there is a correlation between THC intoxication and accidents, that we would expect to see greater incidence rates with higher intoxication levels. The study seems to complete

            • Re:But, but, you're using logic and science (Score:4, Interesting)

              by BronsCon ( 927697 ) <social@bronstrup.com> on Tuesday February 17, 2015 @03:23PM (#49074607) Journal
              Your first paragraph actually agrees with the point I was making; I think you simply misread what I wrote.

              My point was that, if you are correct and they did not account for level of THC intoxication, that would mean that many of the THC-positive subjects likely were not intoxicated at all; e.g. completely sober. Those not-intoxicated but THC-positive subjects should have been recorded under the "Sober" column, which, in turn, would have painted a completely different picture, with many more "Sober" accidents and many fewer "THC-Involved" accidents.

              In other words, I am agreeing with your assessment that level of intoxication is just as important for THC as it is for alcohol.

              My take-away, here, is that the NHTSA did all they could to skew the testing in favor of painting pot in a negative light, while maintaining an appearance of neutrality, and the best they could do was to equate it with sobriety, within a reasonable margin of error.

    • They're using bad science, too.

      Drunk drivers are likely to not get caught their first time. DUI penalties are so high largely on the stated justification that it's probably not their first time--that the police catch you after your 50th or 100th time driving drunk--so we need to penalize you for all the times we've probably missed. There are numerous other problems [drunkdrivingdefense.com] as well.

      It's a valid assumption, but it raises a key consideration:

      drivers with a 0.05% blood-alcohol level were found to be twice as likely to be in a crash. For a person weighing 180 to 190 pounds, that could be a single can of beer, glass of wine, or shot of liquor. At 0.08% (two drinks), the likelihood is quadrupled, and at .20% (four drinks or more), the risk is higher by 23 times.

      To get these conclusions, you would have to measure a person's BAC th

    • Its worse then a "lie", its propaganda, treason, and and a personal assault, done by a subhuman "other", out to destroy everything they hold sacred in life.

  • Um, what? (Score:2, Insightful)

    by Anonymous Coward

    Not that I care about legalisation either way because it's a past time I view as entirely pointless and don't need any kind of drug whether alcohol, tobacco or whatever else to pretend I'm happy, but this:

    "They report that after adjusting for other factors (people who tend to drive after using marijuana also tend to be more crash-prone in general)"

    So by adjusting out people who drive whilst high on marijuana by declaring that they'd have crashed anyway they've managed to show no difference in crash rates?

    No

    • Re: Um, what? (Score:5, Informative)

      by Anonymous Coward on Tuesday February 17, 2015 @09:29AM (#49072967)

      The summary butchered the article (surprisingly). What it should have said was that after adjusting for other factors (namely age and sex) in the group that were in accidents, there was not a difference between using and not using Marijuana.

      For example young men are more likely to be in an accident (Regardless of drug use), they are also more likely to smoke weed compared to other groups.

  • We knew this in the 1970s (Score:5, Informative)

    by io333 ( 574963 ) on Tuesday February 17, 2015 @09:23AM (#49072939)

    Studies more than 40 years old have always consistently shown this, including one I read as a young boy long ago, that showed professional race drivers after mild marijuana intoxication had IMPROVED lap times, though this edge dropped off at higher intoxication levels. Trying to point stuff like this out over the decades had jerkwads accusing me of the most awful things. Whatever I just don't care anymore. Marijuana being illegal while alcohol is not is insanity by definition, but most people are dumb animals and our world is run by sociopaths and there's nothing I can do about it.

  • Booze = Overconfidence, Pot = Paranoia (Score:4, Insightful)

    by retroworks ( 652802 ) on Tuesday February 17, 2015 @09:24AM (#49072947) Homepage Journal

    According to in depth research performed on several subjects throughout the 1960s and 70s, being paranoid makes you drive slower, while lowered inhibitions tend to increase driving speed.

    And loud music was the original "gateway drug".

  • The explaination is quite simple (Score:3)

    by invictusvoyd ( 3546069 ) on Tuesday February 17, 2015 @09:25AM (#49072953)
    For real , this is exactly what happens :

    Alcohol : makes you a moron
    Weed : makes you a really paranoid moron

    People on alcohol lose their hand eye coordination and tend to step on the gas
    People on weed do not lose all of the hand-eye and because of the paranoia , unkowingly drive slowly . That's it ..
    • People high on pot are also often busy watching out for police when they should be spotting that asshole who just ran a red light.

      Don't drive while intoxicated.
    • Why do you assume people on weed don't know they're driving slowly? When I'm high is the one time I adhere to the speed limit, and I damn well do so knowingly.
  • sotally tober .
  • Marijuana does not impair a persons motor skills or reflexes.
    A drunk driver is dangerous because they are likely to lose control of their car.
    A stoned driver is not nearly as dangerous: they can control their car, and react to danger, just fine. The most likely mistake a stoned driver will make is to miss their exit because Stairway to Heaven is on the radio.
    • Hey, that's happened to me and I've never smoked pot.

    • A drunk driver is dangerous because they are likely to lose control of their car.

      The problem with alcohol is that it clouds your judgment. You are not afraid anymore to do stupid things.

      You probably lose control of your car because you were driving to fast for the road, and you drove to fast because you weren't afraid of going through a curve at much to much speed. You probably would have lost control without being drunk, but you wouldn't have got yourself in the situation in the first place.

    • Re: (Score:2)

      by PPH ( 736903 )

      miss their exit because Stairway to Heaven is on the radio.

      In other words; distraction. But distraction can also lead to running over pedestrians crossing the street because you were fixating on something else.

  • Smells like Skunk-scented Bias (Score:3)

    by rmdingler ( 1955220 ) on Tuesday February 17, 2015 @09:33AM (#49073001) Journal
    The alcohol drink-to-intoxication levels are misleading... they appear to assume no time lapse in the consumption of alcoholic drinks. If it takes you two hours to have the four drinks, assuming your liver is in proper working order, two of those drinks are processed out of your system.

    Whenever inaccuracies are reported as fact, it makes the rest of the information less credible.

    FWIW, I condone neither drunk nor stoned operation of a motor vehicle. Sober drivers are distracted enough with ubiquitous cellphone use, eating and talking, putting on makeup, turning around to correct backseat children, et al.

    • Re:Smells like Skunk-scented Bias (Score:5, Informative)

      by duck_rifted ( 3480715 ) on Tuesday February 17, 2015 @09:42AM (#49073057)
      You're looking for information that is not present in that metric, by design, and then claiming a fault because it's not there. And in so doing, you could choose many other pieces of information that aren't there to the same effect. It's very clear that they begin by quantifying the alcohol content of the average "drink" because there are so many *kinds* of drink with alcohol that they'd have to write about a spectrum otherwise. They then consider average body weight to arrive at an average blood alcohol level as a function of "drink".

      If this were *not* their method then they'd basically be suggesting that if you drank a beer two years ago and another one last month, then you're just as intoxicated as somebody who just slammed two bottles of vodka. If you stop to think about how alcohol intoxication is actually quantified for statutory purposes, then what they actually mean becomes obvious.
      • The tone of the article: absorb these statistics with a grain of logic as this is not causality.

        The tone of the summary: Yah! Driving stoned is safe!

        The zealous presentation of the evils of alcohol (commonly understood, mind you) at the end of TFS only serves to reveal the author's bias, rather than clarify his argument. It's like arguing, "Punching someone in the nose is okay, because murdering them is so much worse."

        • Or it could be that the absence of a statistically significant increase in motor accidents occurring while the drivers are under the influence of marijuana does not grant the individual driver magical protections against the risks associated with driving intoxicated.

          ...and driving under the influence of alcohol is most certainly evil. As in, baby-killing evil. As in, running over old women evil. As in, demolishing a stranger's home evil. Literally.

    • 0.05 from a single drink in 180lb person? (Score:5, Informative)

      by Overzeetop ( 214511 ) on Tuesday February 17, 2015 @09:55AM (#49073129) Journal

      What chart are they getting their information from - the pre-teen's guide to Vodka?

      0.05 is the *peak* BAC in a woman weighing less than 100lbs. At 190lbs, man or woman, you're only half way there (0.02-0.025).

      And 0.20 - holy shit, you're well into the "wasted" range and probably are going to have troubles getting the key into the ignition by yourself. For that 180-190lb person, that's shotgunning a .375 flask of Vodka on an empty stomach. Maybe by "four drinks" the poster meant "Four doubles, as made by Bill Cosby at a fraternity hazing initiation"

    • Also, the quoted number of drinks needed to put you in the danger zone (1 drink = 0.05%) doesn't match those found in other studies. In the Netherlands, the traffic bureau advises as a rule of thumb that 2 drinks put you near that limit (which is the legal limit here). Of course they mention that it's an average that can vary wildly, and that it's better to drink nothing at all before driving, but in general the 2 drink rule seems to work fine for most adults.

  • The most dangerous drivers are (Score:4, Insightful)

    by invictusvoyd ( 3546069 ) on Tuesday February 17, 2015 @09:35AM (#49073019)
    Those totally sober people who should have never been given a fucking driving license in the foist place ...

    • Re: (Score:2)

      by Shados ( 741919 )

      Totally agree. Thats why I don't have a license and I just use the subway (even though I'm in my thirties).

      I space out way too much and then to ram in the wall when walking out to work. I just prefer to let someone else do the driving =P

  • DoT & NHTSA Already Knew This (Score:5, Informative)

    by Guy From V ( 1453391 ) on Tuesday February 17, 2015 @09:51AM (#49073109) Homepage

    This study from 1993 (mentioned earlier probably) shows that this was already known to federal authorities, but was probably swept under the rug or willingly ignored by legislators for obvious reasons.

    http://ntl.bts.gov/lib/25000/2... [bts.gov]

  • Meaningless (Score:2, Interesting)

    by markdavis ( 642305 )

    The study is relatively meaningless because it wasn't collecting data about people who were HIGH on marijuana, but people who tested positive for having consumed it at some point. It could have been many hours ago or even days ago.

    The conclusion reached by the horrible article is outright wrong and doesn't even have face validity. In fact, it is actually irresponsible and could cause society great harm by spreading possibly wrong information about the dangers of driving while altered.

    • Re: (Score:2)

      by swb ( 14022 )

      Which highlights the complexity of enforcing "driving while stoned." The ability to detect THC weeks after consumption makes it hard for simple tests like those that exist for alcohol to have any relevance.

      What it does seem to demonstrate is that detecting THC has nothing to do with driving safety, although I would imagine there are a ton of "tough on crime" types who would like to use THC to "prove" intoxication, most likely as a cynical way to restrict its use by holding the risk of DUI prosecution over

  • I believe we should test this, in the real world. Get 30 to 100 people. Setup a course with fake cars and such. Have them all drive it without anything in their system. Then get them drunk and do it again. Then when they are sober, let them smoke pot, and do it again. Then once that is clear have them drink and smoke pot, and go yet again. Then for fun, do it with someone who is just smoking a cig while driving. Compare the results.
    • They did that on Mythbusters, but it was between alcohol intoxication and sleep deprivation. Interestingly they found sleep deprivation to be equally (if not more) debilitating than alcohol intoxication.

      I like the idea for your study, but it would be fun if they also had a test requiring the participants to send a text message or repeatedly answer the phone or set up their GPS while driving.
  • Maybe no increase in accidents but a much higher incident of "dude, you missed that exit (turn, address, city...) again!"

  • "They report that after adjusting for other factors (people who tend to drive after using marijuana also tend to be more crash-prone in general)"

    Wait. As an adjustment, you took out the thing you were looking for and then claimed you couldn't find it?

  • the australian government (Score:3, Interesting)

    by rewindustry ( 3401253 ) on Tuesday February 17, 2015 @03:49PM (#49074843)

    (or related agency) published a detailed study on this subject in the late 90s.

    as far as i remember i found this report on The Well, but i have since lost track of the file, and if anyone knows about it, i would really appreciate a chace to study it again.

    the report was notable, as i remember, because it actually went so far as to suggest that weed makes better drivers - basically because they are more relaxed and therefore more likely to make the correct decisions in an emergency.

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