18 ms·

Stoned drivers are safer than drunk ones, new federal data show

251 points by pkaeding 10y ago

riggins 10y ago
But what about their propensity to drive really slow?
- panzagl 10y ago
  Yeah, I would argue that stoned drivers make everyone else a less safe driver.
- delecti 10y ago
  Given the first paragraph of the article, that doesn't seem to make any difference.
- criley2 10y ago
  >But what about their propensity to drive really slow? You mean like a bicycle, moped, a new parent driving extra slow, an elderly driver, or any other street legal slow vehicle does? I understand that drivers assume the speed LIMIT is a speed suggestion, and experience road rage when driving under the limit, but there is nothing -- nothing -- illegal or unsafe about staying under the speed limit. If there is something unsafe about it, there should be a minimum posted speed (many places have this).
  - throwaway2016a 10y ago
    At least in the US you can get a ticket for going under the speed limit if it is deemed to be impeding traffic even if there is no posted minimum limit. Especially if it is a multi-lane road and you are not in the rightmost lane.
    - criley2 10y ago
      >At least in the US you can get a ticket As a US citizen I will tell you this is false. We have basically no national traffic laws. Your local state, city or other local government may have passed a law like this. For example, in my area, it was made illegal to stay in the left lane moving more slowly than those behind you -- you must yield to the right if they want to go more quickly. But some 99% of Americans do not live under this local law I'm discussing.
      - singlow 10y ago
        Texas has a rule that you may not impede traffic by going below the limit. http://codes.findlaw.com/tx/transportation-code/transp-sect-545-363.html http://codes.findlaw.com/tx/transportation-code/transp-sect-...
        criley2 10y ago
        >except when reduced speed is necessary for safe operation or in compliance with law - See more at: http://codes.findlaw.com/tx/transportation-code/transp-sect-545-363.html#sthash.jYJAFGAa.dpuf http://codes.findlaw.com/tx/transportation-code/transp-sect-... Trivial to argue that reduced speed is required for safe operation in this case, the research in this very article may be useful in that defense
      - bryanlarsen 10y ago
        You're right, it's not national. But as far as I'm aware, all states have general rules against impeding traffic. Many don't have explicit laws against moving too slow in the left lane, but the general law can and will be used against you for egregious violations.
      - ElijahLynn 10y ago
        There are some highways that have a "minimum speed limit" sign posted. Not often, but they do exist, and you can get a ticket on those highways. Also, a Google Self-driving car got pulled over the other day for simply going the speed limit, it did not get a ticket but I thought I would mention it.
  - CraigJPerry 10y ago
    I've seen the result of a driver unexpectedly doing just over 35mph on a moderately busy 70mph motorway. Not nice. I don't even think 35mph is that much slower really - trucks are at 56mph and they get along fine but 35ish resulted in all sorts of crazy last minute swerves. It's generally wise not to do anything other drivers will find surprising and I guess 35mph on a motorway falls in that category.
    - monocasa 10y ago
      Around here, roads that have a maximum speed that fast generally have a minimum speed in the 45MPH range too.
  - odonnellryan 10y ago
    It's definitely unsafe if you're traveling much under the speed limit on a major highway. Most important thing when driving is to be predictable. It's predictable to be traveling plus or minus 10 mph from what is posted. It isn't predicted to be traveling 30mph+ below the speed limit. (no comment on being high, just saying, it's super dangerous to be doing 30-40 on a 65mph road).
- JoeAltmaier 10y ago
  Slowing down is the single most effective thing to reduce traffic accidents and injury. Not good for efficiency or smooth flow, sure. But can't claim its not safer.
  - randunel 10y ago
    > Slowing down is the single most effective thing to reduce traffic accidents and injury. Not good for efficiency or smooth flow, sure. But can't claim its not safer. Go to any motorcycle riding school and all their instructors will teach you that riding slower than the traffic around you is more dangerous than maintaining the average traffic speed, even when above the legal speed limit.
  - MOARDONGZPLZ 10y ago
    Sure, I can make that claim. People driving slow, as you state, aren't good for smooth flow. Have you ever been driving at night at the speed limit and suddenly come upon someone going 15mph under? It's really dangerous.
    - pessimizer 10y ago
      True, but pot isn't making people do that. It's even more dangerous if people completely stop completely, or reverse, at night, on a curved stretch of highway with a 75mph speed limit, but pot isn't making people do that either. I don't even think that pot makes people drive slowly. IMO it's a result of stoned people being afraid of giving the police any excuse to pull them over.
  - JoeAltmaier 10y ago
    Its a matter of degree; of course stopping on the freeway is not a good idea. Here's a stat: Samuel C. Tignor and Davey Warren. "Driver Speed Behavior on U.S. Streets and Highways." Institute of Transportation Engineers: 1990 Compendium of Technical Papers, 1990 August, p. 85. "The accident involvement rates on streets and highways in urban areas was highest for the slowest 5 percent of traffic, lowest for traffic in the 30 to 95 percentile range and increased for the fastest 5 percent of traffic."
  - 10y ago
JPKab 10y ago
As a full supporter of cannabis legalization, I'm also a big supporter of a technology that can instantly detect whether someone's reflexes are impaired by cannabis. Notice that I'm focusing on whether or not they are impaired, as opposed to the amount in their bloodstream. The point being that people that use cannabis regularly for medical reasons don't seem to be impaired by it at all, while newer or more occasional users are certainly impaired. It would be fascinating to see what kind of technologies could be used to achieve this that folks on HN are aware of.
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- ZanyProgrammer 10y ago
  I'd assume regular medical users have gotten very used to the effects of pot, as opposed to noobs.
- amelius 10y ago
  > a technology that can instantly detect whether someone's reflexes are impaired I'm not sure if that would work in practice. As mentioned, alcohol makes someone more confident, or more likely to do stupid things. The test should incorporate that. From another point of view, the alcohol tricks you into thinking your reflexes are still normal, while they are not. And this is the dangerous part, not the fact that your reflexes are somewhat lower (and perhaps comparable to an old lady who is still perfectly capable to drive safely).
  - eikenberry 10y ago
    Why did you switch to alcohol when the parent was talking cannabis. They are very different drugs with very different physiological and psychological effects.
  - sudojudo 10y ago
    >alcohol makes someone more confident, or more likely to do stupid things. Reminds me of the "say the alphabet backwards" challenge that cops often present in sobriety tests. Drunk: ZYX... ZYXW... wait-wait... okay, ZYXTW, ummm... Sober: I can't do that. Stoned: Oh whaaat? No way, man. I can't even do that sober - shit, I mean...
beat 10y ago
Alcohol has two synergetic problems for drivers... it reduces reflexes and increases confidence, simultaneously. Less capable, and more aggressive. No wonder it's so awful for drivers. Marijuana doesn't significantly impair reflexes (as generations of musicians have shown). As for judgment, it tends to make users more cautious, not more aggressive. They're not trying to get around that car in front of them to blow through the used-to-be-yellow light - they're trying to make sure they remember where they're going...
- mankyd 10y ago
  > Marijuana doesn't significantly impair reflexes (as generations of musicians have shown). As an aside, is music really reliant on reflexes like this? I would assume that the beat of a song gives one plenty of forewarning as to when a melody might change. And that assumes that the rhythm of a melody doesn't put you in am altered, hypnotic state in other ways.
  - Raphmedia 10y ago
    Depends. If you are randomly jamming with friends and someone is too stoned, he's going to have one hell of a time trying to keep up if you suddenly go from a slow repetitive bluesy riff to something more rock & roll.
  - singlow 10y ago
    Jazz musicians and other improvisational music require fast reactions to other players.
    - mankyd 10y ago
      But I still wonder if that's not a different skill. Significant changes to the melody still come on the beat. The same can't be said to you driving down the road and the car ahead of you slams on the brakes. Talented musicians of all sort can learn how to improvise, but it's a learned skill, not simply "hey, different music means I do something different!" It's an acquired skill that means training your ear to create cohesive melodies.
oarsinsync 10y ago
> "At the current time, specific drug concentration levels cannot be reliably equated with a specific degree of driver impairment" Massively leading title given the statement actually issued, and their own remarks later on: > There's plenty of evidence showing that marijuana use impairs key driving skills[0]. If you get really stoned and then get behind the wheel, you're asking for trouble. [0]http://www.ncbi.nlm.nih.gov/pubmed/23220273 http://www.ncbi.nlm.nih.gov/pubmed/23220273
- MadManE 10y ago
  But if they told the truth, they wouldn't get upvoted to the front page.
draw_down 10y ago
If anything is true about how this country acts with cannabis, it's that facts and data are pretty much 100% ignored.
_dark_matter_ 10y ago
I wonder if, as public perception changes on the issue, stoned drivers will be in even less accidents as their own perception changes - i.e. "I'm high on cannabis, but that doesn't impair driving, so my own driving isn't impaired", and thus they drive better. Compared to before, "I'm high, high drivers are bad drivers, so my own driving is impaired".
- MaxfordAndSons 10y ago
  I can't imagine that's how cognition and an activity like driving interact. It's not like negative reinforcement in a social setting (getting demoted at work and as a result getting discouraged and becoming a worse performer, for example) - most people realize driving is an inherently dangerous activity, and most people don't want to die (even if they're doing moderately risky things like driving stoned), so they're not going to have an emotional reaction like "Welp! Guess I'm just fated to drive like shit since I'm stoned right now, hope I make it home, but first lets do some donuts." No, they're going to overcompensate and drive more safely. If anything, I'd be concerned the opposite effect would occur - data suggesting that driving stoned is safe will cause stoned drivers to lower their guard and not compensate for their impairment as much, and thus raise stoned driving accident rates.
Symmetry 10y ago
I remember an article on this in New Scientist back in the 90s that went into a lot more depth. A study showed that while alcohol impaired multiple aspects of driving skill marijuana mostly impaired just time judgement. And stoned drivers tended to overestimate their level of impairment and slow down while drunk drivers tended to underestimate how impaired they were. They actually found that drivers who were moderately drunk and stoned were less likely to crash than drivers who were just moderately drunk because they slowed down even though they were more impaired.
- webXL 10y ago
  Right, there's more involved than just the impairment itself. I was just about to ask if this had something to with stoned drivers driving more carefully just to avoid harsher penalties for possession. Data from states where pot is legal would be interesting.
  - Symmetry 10y ago
    In this case the subjects were given substances in a lab and then used a driving simulator.
kdamken 10y ago
Do not read this and think it's okay to drive high. It's not. Do not drive high. Call an uber or something. I worry that people read studies like this and suddenly justify going out and driving while impaired. Driving is an incredibly dangerous activity on its own. Doing it when you're stoned is a stupid and risky move, and comparing it to how much more dangerous drunk driving is doesn't make it less stupid. If you've never smoked pot, you don't understand how it feels and affects your thinking/reactions/perception of time and reality. If you smoke pot everyday, it may affect you less due to tolerance, but it's still affecting you, much like a functional alcoholic. I have nothing against usage and I strongly encourage legalization, but I don't think it's okay to pretend that it's safe to get high and go driving.
- Broken_Hippo 10y ago
  That isn't what the article was saying. I do find it a bit unfair to compare daily smokers to functional alcoholics, however - there is a definite difference in the way the drugs affect folks. This was the main point of the article. A slight buzz like that of a daily smoker - or someone using for medical reasons - isn't affecting safety, but going more than that and it should be obvious. Be safe and all that. Besides. Part of the issue is that public transportation lacking in a lot of parts of the country. Some folks just don't have options, even things like Uber, and if you live just slightly out of the way, such things wind up costing even more money. If you are drunk, you can get arrested in some places (indiana) for walking home - instant public intoxication charge. Still more places don't have safe options to walk or ride bikes if you are impared. These things need fixed to be able to do what you are encouraging.
  - squidfood 10y ago
    The key point in the article is actually the tests used. THC stays in the body long (days/weeks) after you're no longer impaired. If a breathalyzer test on Tuesday picked up the beer you had last Saturday, there'd be no correlation between that test and accidents, either. (and no one would approve of using such a test for law enforcement).
    - 10y ago
mywittyname 10y ago
I can't argue with this data, but I have to wonder how much tolerance/individuality plays a role in this. I know that I personally could not drive high on THC, my propensity to zone out would almost certainly result in an accident, but I (used to) have friends who drove regularly during and after partaking and I was completely confident in their abilities. Personally, I think prohibitionists/law enforcement is looking for an easy money-grab and are hunting for justification of their desires rather than responding to an actual harmful issue that society is facing.
- bluedino 10y ago
  >> I can't argue with this data, but I have to wonder how much tolerance/individuality plays a role in this. A ton. Someone who only drinks a couple times a year and drives home drunk from a wedding or something and isn't used to it is a lot more unsafe than someone who goes to happy hour every day and drives home all the time like that.
  - sokoloff 10y ago
    Maybe on a per-event basis, but probably not on an annual basis.
- lukeschlather 10y ago
  The headline is simply a lie. The study basically showed that you cannot measure whether someone is stoned by testing their blood for THC. The blood test only proves they were stoned at some point in the past few weeks. The study did not show that it's safe to drive while stoned, and if you read the entire article they're fairly clear about that.
  - mywittyname 10y ago
    > The study did not show that it's safe to drive while stoned, and if you read the entire article they're fairly clear about that. Which is exactly what I can't argue with. My point was in reference to the conclusion of the article, which states, > So, should we all assume that we're safe to blaze one and go for a joyride whenever the whimsy strikes us? Absolutely not. There's plenty of evidence showing that marijuana use impairs key driving skills. If you get really stoned and then get behind the wheel, you're asking for trouble. We apparently cannot map concentrations of THC to driver impairment. Which agrees with my anecdotal experience in the matter, that the effects THC vary greatly with individuals.
voidz 10y ago
Get off your high horse.
- nkrisc 10y ago
  Is riding a horse that's high safer than driving while high?
  - OscarCunningham 10y ago
    David Nutt would be the man to find out: http://www.encod.org/info/EQUASY-A-HARMFUL-ADDICTION.html http://www.encod.org/info/EQUASY-A-HARMFUL-ADDICTION.html
- dang 10y ago
  Please don't be personally abusive, even when a comment is annoying. We detached this subthread from https://news.ycombinator.com/item?id=11706682 https://news.ycombinator.com/item?id=11706682 and marked it off-topic.
  - voidz 10y ago
    Sorry. It was intended as a bad pun.
hristov 10y ago
This means nothing. The big difference between alcohol and other drugs is that there is a relatively straightforward correlation between the amount of alcohol in the bloodstream and the current effect of alcohol on the brain. Somebody testing positive for marijuana may not be stoned at all. It could be they were stoned last week and tested positive. Furthermore, alcohol testing is much easier and is the only type of testing really done by police in the field. Police will try to get you to admit being impaired by other drugs if they stop you, but they do not have anything like the breathalyzer to test for other drugs. Current data comparing driving impairment of various drugs and alcohol is almost entirely an artifact of the difference in testing methods.
- vasilipupkin 10y ago
  Yes, the only thing anyone should take away from this data is, we currently do not have reliable data on impairment vs intoxication on THC. Need controlled studies to collect it
chipotle2 10y ago
Maybe they get in fewer accidents because they are driving like 8 miles per hour.
curiousgeorgio 10y ago
You can distort the data all you want, or in this case, put it in an absurd context to try and prove a point, but the fact remains - the legalization of marijuana is not without negative consequences. I'm surprised no one here has mentioned AAA's findings (legalization followed by a 2x increase in fatal marijuana-related crashes): http://newsroom.aaa.com/2016/05/fatal-road-crashes-involving-marijuana-double-state-legalizes-drug/ http://newsroom.aaa.com/2016/05/fatal-road-crashes-involving... EDIT: Link to the study [PDF]: http://publicaffairsresources.aaa.biz/wp-content/uploads/2016/04/Prevalence-of-Marijuana-Involvement-Report-FINAL.pdf http://publicaffairsresources.aaa.biz/wp-content/uploads/201...
- rudolf0 10y ago
  Driving while high should definitely be banned, but it kind of seems like they're making a big assumption here. >The percentage of drivers involved in fatal crashes who recently used marijuana more than doubled from eight to 17 percent between 2013 and 2014. How are they ruling out the fact that since it's been legalized, more people in general are using marijuana?
  - curiousgeorgio 10y ago
    > How are they ruling out the fact that since it's been legalized, more people in general are using marijuana? That's exactly the point. No one is trying to say that driving high has gotten more dangerous as a result of legalization - just that it's inherently dangerous (and a certain percentage of marijuana users are going to be driving either way), so legalization only contributes to more usage, leading to more irresponsible decisions on the road.
    - rudolf0 10y ago
      My point is: They're getting this data by doing drug tests of drivers in fatal car crashes after the crash has occurred. Previously, 8% of those drivers had cannabis detected. Now, 17% have it detected. What evidence is there that the increased cannabis use is causing these crashes, considering you have to control for the fact that more people in general are using cannabis, so in almost any population (drivers in fatal car crashes; fast food employees; school teachers; whatever) you could expect to see an increase in use.
zymhan 10y ago
This is from February of 2015. Nothing about this data is new anymore.
samsonradu 10y ago
I was watching a documentary the other day about life in a Delhi prison and I was thinking to myself if there's the slightest possibility for me to ever end up in prison for one reason or another, considering of course that I don't have the slightest intention of committing a felony. Then I realized that a driving mistake has the best odds of causing such a thing. It's crazy how many don't take such a high-responsibility task seriously, texting, drinking, smoking while driving.
elcapitan 10y ago
On the other hand, studies have shown that red wine is good for the heart and chocolate as well. So the best of all worlds is to get stoned, drink a lot of red wine and then drive while eating chocolate. Why is there no study yet showing that?
binarymax 10y ago
I'm on vacation in Colorado right now, and you can point out the stoned drivers. They tend to drive slow and passive, they fear the merge, and spend lots of time stopped at stop signs making sure they really are stopped and not going to crash. The impression I have is that their judgement and reactions are definitely impaired, but in a stark contrast to the invincibility and carelessness of alcohol induced drivers.
- hfourm 10y ago
  You noticed this just on vacation eh? As a CO resident, maybe you just haven't noticed how shitty our drivers are ;)
  - binarymax 10y ago
    It's purely anecdotal, but I point them out to my sister who has lived here for several years, and she confirms "Yes - definitely stoned."
  - sosborn 10y ago
    > As a CO resident, maybe you just haven't noticed how shitty our drivers are ;) I've lived in many places, including Colorado, and let me tell you – drivers are shitty everywhere :)
- mbrameld 10y ago
  How do you verify your assumptions?
- monocasa 10y ago
  As someone who lives in Colorado, you'd be surprised how many of those people are just "Colorado drivers". I keep asking my mother in law "why are you doing 15 under; you're not even high?" "Oh, it's just so pretty, I wouldn't want to pass everything so quickly". >_< We also call this "meditating while driving" and "'This isn't my bike!? How do I drive something with 4 wheels?'"
- tonyarkles 10y ago
  The old joke back in high school: Drunk drivers ignore red lights, stoned drivers wait for the stop sign to turn green.
brickmort 10y ago
> Stoned drivers are less dangerous than drunk ones
exodust 10y ago
"Safer than drunk" is a poor choice or words, irresponsible even. If you drive within an hour or two or three of smoking sticky buds, the risk is not reflexes or reaction time, it's getting distracted by your own thoughts, or zoning out. That can easily translate into driving through a red light. The mind wanders when stoned, which is the opposite of what you want when operating machinery.
iconjack 10y ago
From the comments here, it seems like people either didn't read the article, or just don't believe the study, because it pretty much says it is ok to smoke and drive. For marijuana, and for a number of other legal and illegal drugs including antidepressants, painkillers, stimulants and the like, there is no statistically significant change in the risk of a crash associated with using that drug prior to driving.
- draw_down 10y ago
  As I mentioned in my other comment, people do not want to hear about studies or other data indicating that marijuana is less dangerous than alcohol. They just do not want to hear it.
- cooper12 10y ago
  Skepticism is healthy. It's quite common for mainstream media to distill a study with tons of caveats and situational results to clickbait like "drinking alcohol means you'll live longer". Not to mention we shouldn't draw any conclusions until reading the paper itself because the article says nothing of their methodology. Lastly with things like the replication crisis and other shoddy results, I don't blame people for not being so fast to believe what common sense would tell them otherwise. [0] Edit, case in point, caveats from the paper itself: > While the findings of this case control study were equivocal with regard to the crash risk associated with drug use by drivers, these results do not indicate that drug use by drivers is risk-free. The study limitations cited above, together with the findings of numerous other studies using different and complementary methods, need to be carefully considered before more definitive conclusions about drug use and crash risk can be reached. > The findings of this study notwithstanding, the established body of scientific evidence on the subject of drug impairment indicates that in some situations, drugs other than alcohol can seriously impair driving ability. Oh, and you really should read articles all the way through: > So, should we all assume that we're safe to blaze one and go for a joyride whenever the whimsy strikes us? Absolutely not. There's plenty of evidence showing that marijuana use impairs key driving skills. If you get really stoned and then get behind the wheel, you're asking for trouble. [0]: https://en.wikipedia.org/wiki/Replication_crisis https://en.wikipedia.org/wiki/Replication_crisis
- 10y ago
vlunkr 10y ago
That chart has sections for both "Any Legal Drug" and "Any Illegal Drug", and both bars are barely visible. Are they claiming that all drugs, legal or not, don't affect driving?? Because that would be an incredibly stupid claim.
dimino 10y ago
I'm going to upgrade my view of this article to linkbait title. The title should be, "THC found to not correlate with impairment in the same way that blood alcohol concentration does". From the article: > The study's findings underscore an important point: that the measurable presence of THC (marijuana's primary active ingredient) in a person's system doesn't correlate with impairment in the same way that blood alcohol concentration does. The story here is that there is no "THC impairment" test like there is a blood alcohol test, not that driving while stoned is safer.
bunkydoo 10y ago
I'm a bit curious if the "any illegal drug" column includes LSD or hallucinogens. Part of me thinks most people have the common sense not to drive while on such a substance, part of me thinks there would be no way to gather data
green_lunch 10y ago
It's studies like this that have caused people in my city to support legally driving while high. I've seen so many people that somehow think there is no effect on driving skills. I'm all for legalization, but I will not support the potential of endangering other people.
mjhm2539 10y ago
"Neighbor beats his wife less often than other neighbor, new federal data shows"
musgrove 10y ago
I think a lot of people could have told them that. Including, most likely, some of the researchers themselves as well as a few presidents, especially our current one, and most Kennedys.
RichardCA 10y ago
Carl Sagan had some things to say about this topic. http://marijuana-uses.com/mr-x/ http://marijuana-uses.com/mr-x/
slipperyp 10y ago
KIRO TV in Seattle did a small test of impairment on a closed course with participants using varying amounts of marijuana a few years ago around the time Washington voters were choosing to legalize pot and found similar results: http://www.kiro7.com/news/stoned-drivers-hit-test-course/139144424 http://www.kiro7.com/news/stoned-drivers-hit-test-course/139...
cphoover 10y ago
Confirming what everyone already knew. Also... Driving impaired in anyway is a big mistake.
ck2 10y ago
I've had two friends killed by drunk drivers in two different decades and I have to run on the side of the road If you are on anything, legal or illegal that influences you, I hope you get a nice long prison sentence for driving impaired. If you see someone step out of a bar or whatnot that is either drunk or high and goes to drive, please call the police and possibly save someone's life - you don't have to call 911, call the anonymous number for your city.
return0 10y ago
Both should only be allowed to drive self-driving cars.
kalehrishi 10y ago
They must be smoking good stuff when they decided to publish this article :D
jacquesm 10y ago
The only valid comparison is with a driver that is sober.
breatheoften 10y ago
Are there any ways to directly measure impairment rather than using chemical trace detection as a proxy for the affect? Maybe a driver could take a short impairment test on their cellphone or in car computer prior to starting their drive -- if they pass the test then they would have an argument against impairement should they become subsequently involved in an accident... If they fail the test and drive anyway then there's an even stronger argument that they made an irresponsible decision for which they must take responsibility.
WelcomeToHeaven 10y ago
Was federal data really needed to determine stoned drivers are safer than drunk ones? I thought it would be known that drunk driving is more dangerous than stoned driving.
skuunk1 10y ago
The title seems misleading. People with marijuana in their bloodstream != stoned drivers. Marijuana use is detectable for a long time past the point of impairment and the data only reflects that they HAVE used marijuana vs being stoned at the point of driving. Maybe instead of breathalysers and drug detection kits we should have standardised attention/reaction tests to determine if someone is safe to drive (you could probably even run them on a tablet). This would also weed out (pun intended) tired drivers.

251 points by pkaeding 10y ago

riggins 10y ago

But what about their propensity to drive really slow?

panzagl 10y ago
Yeah, I would argue that stoned drivers make everyone else a less safe driver.
delecti 10y ago
Given the first paragraph of the article, that doesn't seem to make any difference.
criley2 10y ago
>But what about their propensity to drive really slow? You mean like a bicycle, moped, a new parent driving extra slow, an elderly driver, or any other street legal slow vehicle does? I understand that drivers assume the speed LIMIT is a speed suggestion, and experience road rage when driving under the limit, but there is nothing -- nothing -- illegal or unsafe about staying under the speed limit. If there is something unsafe about it, there should be a minimum posted speed (many places have this).
- throwaway2016a 10y ago
  At least in the US you can get a ticket for going under the speed limit if it is deemed to be impeding traffic even if there is no posted minimum limit. Especially if it is a multi-lane road and you are not in the rightmost lane.
  - criley2 10y ago
    >At least in the US you can get a ticket As a US citizen I will tell you this is false. We have basically no national traffic laws. Your local state, city or other local government may have passed a law like this. For example, in my area, it was made illegal to stay in the left lane moving more slowly than those behind you -- you must yield to the right if they want to go more quickly. But some 99% of Americans do not live under this local law I'm discussing.
    - singlow 10y ago
      Texas has a rule that you may not impede traffic by going below the limit. http://codes.findlaw.com/tx/transportation-code/transp-sect-545-363.html http://codes.findlaw.com/tx/transportation-code/transp-sect-...
      - criley2 10y ago
        >except when reduced speed is necessary for safe operation or in compliance with law - See more at: http://codes.findlaw.com/tx/transportation-code/transp-sect-545-363.html#sthash.jYJAFGAa.dpuf http://codes.findlaw.com/tx/transportation-code/transp-sect-... Trivial to argue that reduced speed is required for safe operation in this case, the research in this very article may be useful in that defense
    - bryanlarsen 10y ago
      You're right, it's not national. But as far as I'm aware, all states have general rules against impeding traffic. Many don't have explicit laws against moving too slow in the left lane, but the general law can and will be used against you for egregious violations.
    - ElijahLynn 10y ago
      There are some highways that have a "minimum speed limit" sign posted. Not often, but they do exist, and you can get a ticket on those highways. Also, a Google Self-driving car got pulled over the other day for simply going the speed limit, it did not get a ticket but I thought I would mention it.
- CraigJPerry 10y ago
  I've seen the result of a driver unexpectedly doing just over 35mph on a moderately busy 70mph motorway. Not nice. I don't even think 35mph is that much slower really - trucks are at 56mph and they get along fine but 35ish resulted in all sorts of crazy last minute swerves. It's generally wise not to do anything other drivers will find surprising and I guess 35mph on a motorway falls in that category.
  - monocasa 10y ago
    Around here, roads that have a maximum speed that fast generally have a minimum speed in the 45MPH range too.
- odonnellryan 10y ago
  It's definitely unsafe if you're traveling much under the speed limit on a major highway. Most important thing when driving is to be predictable. It's predictable to be traveling plus or minus 10 mph from what is posted. It isn't predicted to be traveling 30mph+ below the speed limit. (no comment on being high, just saying, it's super dangerous to be doing 30-40 on a 65mph road).
JoeAltmaier 10y ago
Slowing down is the single most effective thing to reduce traffic accidents and injury. Not good for efficiency or smooth flow, sure. But can't claim its not safer.
- randunel 10y ago
  > Slowing down is the single most effective thing to reduce traffic accidents and injury. Not good for efficiency or smooth flow, sure. But can't claim its not safer. Go to any motorcycle riding school and all their instructors will teach you that riding slower than the traffic around you is more dangerous than maintaining the average traffic speed, even when above the legal speed limit.
- MOARDONGZPLZ 10y ago
  Sure, I can make that claim. People driving slow, as you state, aren't good for smooth flow. Have you ever been driving at night at the speed limit and suddenly come upon someone going 15mph under? It's really dangerous.
  - pessimizer 10y ago
    True, but pot isn't making people do that. It's even more dangerous if people completely stop completely, or reverse, at night, on a curved stretch of highway with a 75mph speed limit, but pot isn't making people do that either. I don't even think that pot makes people drive slowly. IMO it's a result of stoned people being afraid of giving the police any excuse to pull them over.
- JoeAltmaier 10y ago
  Its a matter of degree; of course stopping on the freeway is not a good idea. Here's a stat: Samuel C. Tignor and Davey Warren. "Driver Speed Behavior on U.S. Streets and Highways." Institute of Transportation Engineers: 1990 Compendium of Technical Papers, 1990 August, p. 85. "The accident involvement rates on streets and highways in urban areas was highest for the slowest 5 percent of traffic, lowest for traffic in the 30 to 95 percentile range and increased for the fastest 5 percent of traffic."
- 10y ago

JPKab 10y ago

As a full supporter of cannabis legalization, I'm also a big supporter of a technology that can instantly detect whether someone's reflexes are impaired by cannabis. Notice that I'm focusing on whether or not they are impaired, as opposed to the amount in their bloodstream. The point being that people that use cannabis regularly for medical reasons don't seem to be impaired by it at all, while newer or more occasional users are certainly impaired. It would be fascinating to see what kind of technologies could be used to achieve this that folks on HN are aware of.

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ZanyProgrammer 10y ago
I'd assume regular medical users have gotten very used to the effects of pot, as opposed to noobs.
amelius 10y ago
> a technology that can instantly detect whether someone's reflexes are impaired I'm not sure if that would work in practice. As mentioned, alcohol makes someone more confident, or more likely to do stupid things. The test should incorporate that. From another point of view, the alcohol tricks you into thinking your reflexes are still normal, while they are not. And this is the dangerous part, not the fact that your reflexes are somewhat lower (and perhaps comparable to an old lady who is still perfectly capable to drive safely).
- eikenberry 10y ago
  Why did you switch to alcohol when the parent was talking cannabis. They are very different drugs with very different physiological and psychological effects.
- sudojudo 10y ago
  >alcohol makes someone more confident, or more likely to do stupid things. Reminds me of the "say the alphabet backwards" challenge that cops often present in sobriety tests. Drunk: ZYX... ZYXW... wait-wait... okay, ZYXTW, ummm... Sober: I can't do that. Stoned: Oh whaaat? No way, man. I can't even do that sober - shit, I mean...

beat 10y ago

Alcohol has two synergetic problems for drivers... it reduces reflexes and increases confidence, simultaneously. Less capable, and more aggressive. No wonder it's so awful for drivers. Marijuana doesn't significantly impair reflexes (as generations of musicians have shown). As for judgment, it tends to make users more cautious, not more aggressive. They're not trying to get around that car in front of them to blow through the used-to-be-yellow light - they're trying to make sure they remember where they're going...

mankyd 10y ago
> Marijuana doesn't significantly impair reflexes (as generations of musicians have shown). As an aside, is music really reliant on reflexes like this? I would assume that the beat of a song gives one plenty of forewarning as to when a melody might change. And that assumes that the rhythm of a melody doesn't put you in am altered, hypnotic state in other ways.
- Raphmedia 10y ago
  Depends. If you are randomly jamming with friends and someone is too stoned, he's going to have one hell of a time trying to keep up if you suddenly go from a slow repetitive bluesy riff to something more rock & roll.
- singlow 10y ago
  Jazz musicians and other improvisational music require fast reactions to other players.
  - mankyd 10y ago
    But I still wonder if that's not a different skill. Significant changes to the melody still come on the beat. The same can't be said to you driving down the road and the car ahead of you slams on the brakes. Talented musicians of all sort can learn how to improvise, but it's a learned skill, not simply "hey, different music means I do something different!" It's an acquired skill that means training your ear to create cohesive melodies.

oarsinsync 10y ago

> "At the current time, specific drug concentration levels cannot be reliably equated with a specific degree of driver impairment" Massively leading title given the statement actually issued, and their own remarks later on: > There's plenty of evidence showing that marijuana use impairs key driving skills[0]. If you get really stoned and then get behind the wheel, you're asking for trouble. [0]http://www.ncbi.nlm.nih.gov/pubmed/23220273 http://www.ncbi.nlm.nih.gov/pubmed/23220273

MadManE 10y ago
But if they told the truth, they wouldn't get upvoted to the front page.

draw_down 10y ago

If anything is true about how this country acts with cannabis, it's that facts and data are pretty much 100% ignored.

_dark_matter_ 10y ago

I wonder if, as public perception changes on the issue, stoned drivers will be in even less accidents as their own perception changes - i.e. "I'm high on cannabis, but that doesn't impair driving, so my own driving isn't impaired", and thus they drive better. Compared to before, "I'm high, high drivers are bad drivers, so my own driving is impaired".

MaxfordAndSons 10y ago
I can't imagine that's how cognition and an activity like driving interact. It's not like negative reinforcement in a social setting (getting demoted at work and as a result getting discouraged and becoming a worse performer, for example) - most people realize driving is an inherently dangerous activity, and most people don't want to die (even if they're doing moderately risky things like driving stoned), so they're not going to have an emotional reaction like "Welp! Guess I'm just fated to drive like shit since I'm stoned right now, hope I make it home, but first lets do some donuts." No, they're going to overcompensate and drive more safely. If anything, I'd be concerned the opposite effect would occur - data suggesting that driving stoned is safe will cause stoned drivers to lower their guard and not compensate for their impairment as much, and thus raise stoned driving accident rates.

Symmetry 10y ago

I remember an article on this in New Scientist back in the 90s that went into a lot more depth. A study showed that while alcohol impaired multiple aspects of driving skill marijuana mostly impaired just time judgement. And stoned drivers tended to overestimate their level of impairment and slow down while drunk drivers tended to underestimate how impaired they were. They actually found that drivers who were moderately drunk and stoned were less likely to crash than drivers who were just moderately drunk because they slowed down even though they were more impaired.

webXL 10y ago
Right, there's more involved than just the impairment itself. I was just about to ask if this had something to with stoned drivers driving more carefully just to avoid harsher penalties for possession. Data from states where pot is legal would be interesting.
- Symmetry 10y ago
  In this case the subjects were given substances in a lab and then used a driving simulator.

kdamken 10y ago

Do not read this and think it's okay to drive high. It's not. Do not drive high. Call an uber or something. I worry that people read studies like this and suddenly justify going out and driving while impaired. Driving is an incredibly dangerous activity on its own. Doing it when you're stoned is a stupid and risky move, and comparing it to how much more dangerous drunk driving is doesn't make it less stupid. If you've never smoked pot, you don't understand how it feels and affects your thinking/reactions/perception of time and reality. If you smoke pot everyday, it may affect you less due to tolerance, but it's still affecting you, much like a functional alcoholic. I have nothing against usage and I strongly encourage legalization, but I don't think it's okay to pretend that it's safe to get high and go driving.

Broken_Hippo 10y ago
That isn't what the article was saying. I do find it a bit unfair to compare daily smokers to functional alcoholics, however - there is a definite difference in the way the drugs affect folks. This was the main point of the article. A slight buzz like that of a daily smoker - or someone using for medical reasons - isn't affecting safety, but going more than that and it should be obvious. Be safe and all that. Besides. Part of the issue is that public transportation lacking in a lot of parts of the country. Some folks just don't have options, even things like Uber, and if you live just slightly out of the way, such things wind up costing even more money. If you are drunk, you can get arrested in some places (indiana) for walking home - instant public intoxication charge. Still more places don't have safe options to walk or ride bikes if you are impared. These things need fixed to be able to do what you are encouraging.
- squidfood 10y ago
  The key point in the article is actually the tests used. THC stays in the body long (days/weeks) after you're no longer impaired. If a breathalyzer test on Tuesday picked up the beer you had last Saturday, there'd be no correlation between that test and accidents, either. (and no one would approve of using such a test for law enforcement).
  - 10y ago

mywittyname 10y ago

I can't argue with this data, but I have to wonder how much tolerance/individuality plays a role in this. I know that I personally could not drive high on THC, my propensity to zone out would almost certainly result in an accident, but I (used to) have friends who drove regularly during and after partaking and I was completely confident in their abilities. Personally, I think prohibitionists/law enforcement is looking for an easy money-grab and are hunting for justification of their desires rather than responding to an actual harmful issue that society is facing.

bluedino 10y ago
>> I can't argue with this data, but I have to wonder how much tolerance/individuality plays a role in this. A ton. Someone who only drinks a couple times a year and drives home drunk from a wedding or something and isn't used to it is a lot more unsafe than someone who goes to happy hour every day and drives home all the time like that.
- sokoloff 10y ago
  Maybe on a per-event basis, but probably not on an annual basis.
lukeschlather 10y ago
The headline is simply a lie. The study basically showed that you cannot measure whether someone is stoned by testing their blood for THC. The blood test only proves they were stoned at some point in the past few weeks. The study did not show that it's safe to drive while stoned, and if you read the entire article they're fairly clear about that.
- mywittyname 10y ago
  > The study did not show that it's safe to drive while stoned, and if you read the entire article they're fairly clear about that. Which is exactly what I can't argue with. My point was in reference to the conclusion of the article, which states, > So, should we all assume that we're safe to blaze one and go for a joyride whenever the whimsy strikes us? Absolutely not. There's plenty of evidence showing that marijuana use impairs key driving skills. If you get really stoned and then get behind the wheel, you're asking for trouble. We apparently cannot map concentrations of THC to driver impairment. Which agrees with my anecdotal experience in the matter, that the effects THC vary greatly with individuals.

voidz 10y ago

Get off your high horse.

nkrisc 10y ago
Is riding a horse that's high safer than driving while high?
- OscarCunningham 10y ago
  David Nutt would be the man to find out: http://www.encod.org/info/EQUASY-A-HARMFUL-ADDICTION.html http://www.encod.org/info/EQUASY-A-HARMFUL-ADDICTION.html
dang 10y ago
Please don't be personally abusive, even when a comment is annoying. We detached this subthread from https://news.ycombinator.com/item?id=11706682 https://news.ycombinator.com/item?id=11706682 and marked it off-topic.
- voidz 10y ago
  Sorry. It was intended as a bad pun.

hristov 10y ago

This means nothing. The big difference between alcohol and other drugs is that there is a relatively straightforward correlation between the amount of alcohol in the bloodstream and the current effect of alcohol on the brain. Somebody testing positive for marijuana may not be stoned at all. It could be they were stoned last week and tested positive. Furthermore, alcohol testing is much easier and is the only type of testing really done by police in the field. Police will try to get you to admit being impaired by other drugs if they stop you, but they do not have anything like the breathalyzer to test for other drugs. Current data comparing driving impairment of various drugs and alcohol is almost entirely an artifact of the difference in testing methods.

vasilipupkin 10y ago
Yes, the only thing anyone should take away from this data is, we currently do not have reliable data on impairment vs intoxication on THC. Need controlled studies to collect it

chipotle2 10y ago

Maybe they get in fewer accidents because they are driving like 8 miles per hour.

curiousgeorgio 10y ago

You can distort the data all you want, or in this case, put it in an absurd context to try and prove a point, but the fact remains - the legalization of marijuana is not without negative consequences. I'm surprised no one here has mentioned AAA's findings (legalization followed by a 2x increase in fatal marijuana-related crashes): http://newsroom.aaa.com/2016/05/fatal-road-crashes-involving-marijuana-double-state-legalizes-drug/ http://newsroom.aaa.com/2016/05/fatal-road-crashes-involving... EDIT: Link to the study [PDF]: http://publicaffairsresources.aaa.biz/wp-content/uploads/2016/04/Prevalence-of-Marijuana-Involvement-Report-FINAL.pdf http://publicaffairsresources.aaa.biz/wp-content/uploads/201...

rudolf0 10y ago
Driving while high should definitely be banned, but it kind of seems like they're making a big assumption here. >The percentage of drivers involved in fatal crashes who recently used marijuana more than doubled from eight to 17 percent between 2013 and 2014. How are they ruling out the fact that since it's been legalized, more people in general are using marijuana?
- curiousgeorgio 10y ago
  > How are they ruling out the fact that since it's been legalized, more people in general are using marijuana? That's exactly the point. No one is trying to say that driving high has gotten more dangerous as a result of legalization - just that it's inherently dangerous (and a certain percentage of marijuana users are going to be driving either way), so legalization only contributes to more usage, leading to more irresponsible decisions on the road.
  - rudolf0 10y ago
    My point is: They're getting this data by doing drug tests of drivers in fatal car crashes after the crash has occurred. Previously, 8% of those drivers had cannabis detected. Now, 17% have it detected. What evidence is there that the increased cannabis use is causing these crashes, considering you have to control for the fact that more people in general are using cannabis, so in almost any population (drivers in fatal car crashes; fast food employees; school teachers; whatever) you could expect to see an increase in use.

zymhan 10y ago

This is from February of 2015. Nothing about this data is new anymore.

samsonradu 10y ago

I was watching a documentary the other day about life in a Delhi prison and I was thinking to myself if there's the slightest possibility for me to ever end up in prison for one reason or another, considering of course that I don't have the slightest intention of committing a felony. Then I realized that a driving mistake has the best odds of causing such a thing. It's crazy how many don't take such a high-responsibility task seriously, texting, drinking, smoking while driving.

elcapitan 10y ago

On the other hand, studies have shown that red wine is good for the heart and chocolate as well. So the best of all worlds is to get stoned, drink a lot of red wine and then drive while eating chocolate. Why is there no study yet showing that?

binarymax 10y ago

I'm on vacation in Colorado right now, and you can point out the stoned drivers. They tend to drive slow and passive, they fear the merge, and spend lots of time stopped at stop signs making sure they really are stopped and not going to crash. The impression I have is that their judgement and reactions are definitely impaired, but in a stark contrast to the invincibility and carelessness of alcohol induced drivers.

hfourm 10y ago
You noticed this just on vacation eh? As a CO resident, maybe you just haven't noticed how shitty our drivers are ;)
- binarymax 10y ago
  It's purely anecdotal, but I point them out to my sister who has lived here for several years, and she confirms "Yes - definitely stoned."
- sosborn 10y ago
  > As a CO resident, maybe you just haven't noticed how shitty our drivers are ;) I've lived in many places, including Colorado, and let me tell you – drivers are shitty everywhere :)
mbrameld 10y ago
How do you verify your assumptions?
monocasa 10y ago
As someone who lives in Colorado, you'd be surprised how many of those people are just "Colorado drivers". I keep asking my mother in law "why are you doing 15 under; you're not even high?" "Oh, it's just so pretty, I wouldn't want to pass everything so quickly". >_< We also call this "meditating while driving" and "'This isn't my bike!? How do I drive something with 4 wheels?'"
tonyarkles 10y ago
The old joke back in high school: Drunk drivers ignore red lights, stoned drivers wait for the stop sign to turn green.

brickmort 10y ago

> Stoned drivers are less dangerous than drunk ones

exodust 10y ago

"Safer than drunk" is a poor choice or words, irresponsible even. If you drive within an hour or two or three of smoking sticky buds, the risk is not reflexes or reaction time, it's getting distracted by your own thoughts, or zoning out. That can easily translate into driving through a red light. The mind wanders when stoned, which is the opposite of what you want when operating machinery.

iconjack 10y ago

From the comments here, it seems like people either didn't read the article, or just don't believe the study, because it pretty much says it is ok to smoke and drive. For marijuana, and for a number of other legal and illegal drugs including antidepressants, painkillers, stimulants and the like, there is no statistically significant change in the risk of a crash associated with using that drug prior to driving.

draw_down 10y ago
As I mentioned in my other comment, people do not want to hear about studies or other data indicating that marijuana is less dangerous than alcohol. They just do not want to hear it.
cooper12 10y ago
Skepticism is healthy. It's quite common for mainstream media to distill a study with tons of caveats and situational results to clickbait like "drinking alcohol means you'll live longer". Not to mention we shouldn't draw any conclusions until reading the paper itself because the article says nothing of their methodology. Lastly with things like the replication crisis and other shoddy results, I don't blame people for not being so fast to believe what common sense would tell them otherwise. [0] Edit, case in point, caveats from the paper itself: > While the findings of this case control study were equivocal with regard to the crash risk associated with drug use by drivers, these results do not indicate that drug use by drivers is risk-free. The study limitations cited above, together with the findings of numerous other studies using different and complementary methods, need to be carefully considered before more definitive conclusions about drug use and crash risk can be reached. > The findings of this study notwithstanding, the established body of scientific evidence on the subject of drug impairment indicates that in some situations, drugs other than alcohol can seriously impair driving ability. Oh, and you really should read articles all the way through: > So, should we all assume that we're safe to blaze one and go for a joyride whenever the whimsy strikes us? Absolutely not. There's plenty of evidence showing that marijuana use impairs key driving skills. If you get really stoned and then get behind the wheel, you're asking for trouble. [0]: https://en.wikipedia.org/wiki/Replication_crisis https://en.wikipedia.org/wiki/Replication_crisis
10y ago

vlunkr 10y ago

That chart has sections for both "Any Legal Drug" and "Any Illegal Drug", and both bars are barely visible. Are they claiming that all drugs, legal or not, don't affect driving?? Because that would be an incredibly stupid claim.

dimino 10y ago

I'm going to upgrade my view of this article to linkbait title. The title should be, "THC found to not correlate with impairment in the same way that blood alcohol concentration does". From the article: > The study's findings underscore an important point: that the measurable presence of THC (marijuana's primary active ingredient) in a person's system doesn't correlate with impairment in the same way that blood alcohol concentration does. The story here is that there is no "THC impairment" test like there is a blood alcohol test, not that driving while stoned is safer.

bunkydoo 10y ago

I'm a bit curious if the "any illegal drug" column includes LSD or hallucinogens. Part of me thinks most people have the common sense not to drive while on such a substance, part of me thinks there would be no way to gather data

green_lunch 10y ago

It's studies like this that have caused people in my city to support legally driving while high. I've seen so many people that somehow think there is no effect on driving skills. I'm all for legalization, but I will not support the potential of endangering other people.

mjhm2539 10y ago

"Neighbor beats his wife less often than other neighbor, new federal data shows"

musgrove 10y ago

I think a lot of people could have told them that. Including, most likely, some of the researchers themselves as well as a few presidents, especially our current one, and most Kennedys.

RichardCA 10y ago

Carl Sagan had some things to say about this topic. http://marijuana-uses.com/mr-x/ http://marijuana-uses.com/mr-x/

slipperyp 10y ago

KIRO TV in Seattle did a small test of impairment on a closed course with participants using varying amounts of marijuana a few years ago around the time Washington voters were choosing to legalize pot and found similar results: http://www.kiro7.com/news/stoned-drivers-hit-test-course/139144424 http://www.kiro7.com/news/stoned-drivers-hit-test-course/139...

cphoover 10y ago

Confirming what everyone already knew. Also... Driving impaired in anyway is a big mistake.

ck2 10y ago

I've had two friends killed by drunk drivers in two different decades and I have to run on the side of the road If you are on anything, legal or illegal that influences you, I hope you get a nice long prison sentence for driving impaired. If you see someone step out of a bar or whatnot that is either drunk or high and goes to drive, please call the police and possibly save someone's life - you don't have to call 911, call the anonymous number for your city.

return0 10y ago

Both should only be allowed to drive self-driving cars.

kalehrishi 10y ago

They must be smoking good stuff when they decided to publish this article :D

jacquesm 10y ago

The only valid comparison is with a driver that is sober.

breatheoften 10y ago

Are there any ways to directly measure impairment rather than using chemical trace detection as a proxy for the affect? Maybe a driver could take a short impairment test on their cellphone or in car computer prior to starting their drive -- if they pass the test then they would have an argument against impairement should they become subsequently involved in an accident... If they fail the test and drive anyway then there's an even stronger argument that they made an irresponsible decision for which they must take responsibility.

WelcomeToHeaven 10y ago

Was federal data really needed to determine stoned drivers are safer than drunk ones? I thought it would be known that drunk driving is more dangerous than stoned driving.

skuunk1 10y ago

The title seems misleading. People with marijuana in their bloodstream != stoned drivers. Marijuana use is detectable for a long time past the point of impairment and the data only reflects that they HAVE used marijuana vs being stoned at the point of driving. Maybe instead of breathalysers and drug detection kits we should have standardised attention/reaction tests to determine if someone is safe to drive (you could probably even run them on a tablet). This would also weed out (pun intended) tired drivers.