This is interesting but the causal relationship inferred by the article isn't supported by the evidence.
Unlike alcohol for example, there's no clear dose of THC where it can be concluded beyond a reasonable doubt that the person is impaired. A dose that might give a regular user a gentle buzz could render a first-time user completely stoned.
It's possible that these people were all incredibly stoned while driving but it's also possible that many drivers in Ohio are regular THC users and have such a high tolerance that their function is unimpaired.
And like always, there's the definite possibility of confounding factors, like reckless drivers also enjoying recreational drug use.
It's also important to note that the article's focus on legal limits is somewhat pointless. As there's no clear threshold above which one is impaired, the legal limits are somewhat arbitrary and are determined by other factors, like whether THC can be reliably tested at the given concentration.
Ultimately, as far as I can tell, the current state of things is that we're fairly certain that THC is able to impair driving ability but we have no idea how much THC is needed to do it or how impaired drivers become.
If we’re going to be this cruel it only makes sense to apply the same penalty to using a smartphone while driving, since it results in the same level of reaction time impairment as DWI.
>So until we have more research, we legislate to the case of the "first-time user completely stoned," no?
Throwing everyone under the bus because of the lowest common denominator is a shitty thing to do when we're talking $10k+ life altering fines here, but your attitude is how everything else involving driving is done so you'll probably get your way even if it's not moral or right.
INB4 people call me a stoner, haven't smoked weed in decades.
Can you point out where it ‘infers’ a causal relationship? The article as posted only makes the point that the percentage of dead people with THC in their system has remained static despite legalization.
> A dose that might give a regular user a gentle buzz could render a first-time user completely stoned.
> It's possible that these people were all incredibly stoned while driving but it's also possible that many drivers in Ohio are regular THC users and have such a high tolerance that their function is unimpaired.
Can't you make this same argument with alcohol?
> Ultimately, as far as I can tell, the current state of things is that we're fairly certain that THC is able to impair driving ability but we have no idea how much THC is needed to do it or how impaired drivers become.
So how exactly would you propose states move forward with allowing people to consume THC and operate vehicles (or not)? We apparently can't even tell if someone is impaired in a reliable way.
Increased tolerance to THC actually makes it get you less high (for lack of a better term). You need a higher dose to be the same level of impaired. Real stoners can be totally functional and barely even high while hitting a vape every few minutes, but a first-time cannabis user might be on the floor after a single hit.
AFAIK the same isn’t true of alcohol - people who drink a lot may learn to be more functional while drunk, but I don’t believe that someone with a high tolerance has any faster of a reaction time than someone with a low tolerance, if their BACs are the same.
Technically the same thing applies, but to a much, much lesser degree.
While it's true that alcoholics can perform most tasks better than the average person after a few drinks, and there is some data showing they are less likely to get in accidents after drinking, they still become significantly impaired at about the same rate as everyone else.
They might have an advantage of a few drinks compared to a regular person, but they often close that gap.
The amount of non-impaired alcoholics driving around with BACs above the legal limit is negligible.
The human body's ability to adapt to THC is far greater than its ability to adapt to alcohol.
The Endocannabinoid system safely saturates, you can only have so much before the next dose doesn't really do much more.
Alcohol, on the other hand, continues to have about the same marginal effect, until toxicity is reached.
> While it's true that alcoholics can perform most tasks better than the average person after a few drinks, and there is some data showing they are less likely to get in accidents after drinking, they still become significantly impaired at about the same rate as everyone else.
This is completely self contradictory. It’s absolutely not “the same rate” if alcoholics can drink multiple additional drinks without showing impairment compared to nonalcoholics.
> They might have an advantage of a few drinks compared to a regular person, but they often close that gap.
This is kind of absurd. “Yeah, they can drink way more without impairment, but they’ll probably still drink to impairment.” This is borderline future crime.
I certainly don’t think we should allow alcoholics to drive with a higher BAC, mostly because the entire point of BAC is to make assessment more objective, but your logic is pretty tortured here.
I'm speaking in comparison to THC.
We are talking about order of magnitude differences with THC, especially in the blood after smoking or vaporizing.
The difference between a little drunk and very drunk is only a factor of 2, probably less.
I don't even think it's possible for a human to be 4 times as drunk as another also drunk human and survive.
The best way to think about tolerance to alcohol is buying a small constant headstart, while THC is better modeled as a difference of rates depending on tolerance.
I think most people will find that model useful, and the numbers (BAC) support that as a rule of thumb calculation.
Somehow you disagree that my model is accurate enough, but also agree that a constant cutoff is a good heuristic for legal intoxication from alcohol.
I have no idea about THC tolerance in comparison with alcohol. The numbers I see some people claim to consume is in your order of magnitude range vs what beginners are advised to use so it’s believable.
> Somehow you disagree that my model is accurate enough, but also agree that a constant cutoff is a good heuristic for legal intoxication from alcohol.
It’s not that I think your model isn’t accurate enough. It’s that I think your model is not consistent. A few extra drinks is enough to go from just barely under .08 to .16. If an alcoholic can run nearly double the alcohol intake (and double the BAC) of a nonalcoholic I don’t agree that this is nearly the same.
I agree with the constant cutoff because a constant reasonable limit is easier to administer. Less subjectivity for law enforcement is a good thing. I would probably support for the same for THC. “But I consume so much that I have a really high tolerance!” Ok, that’s not everyone else’s problem to deal with. Don’t drink if you’re over the limit.
> They might have an advantage of a few drinks compared to a regular person, but they often close that gap.
When the legal limit is 0.08 or lower, that's the difference between "too drunk for a non-alcoholic to drive" and "perfectly fine for an alcoholic", isn't it? Yet no court would accept that as an argument.
No because a once-daily user of THC will continue to test positive for 14+ days after quitting completely. For alcohol it's 6-12 hours. They are not comparable.
No, I was referring to the argument about tolerance.
"Your honor, my client is a raging alcoholic. Yes he blew 0.2, and while that may make the average person highly intoxicated, my client can function perfectly well at that level."
It is very hard to determine for thc-based intoxication via a test to determine not only when the person was intoxicated, but to what degree. They could have been stoned a week ago, or two weeks ago.
Other commentators are pointing out and linking to sources that explain how the tolerance bio-mechanisms are very different between alcohol and marijuana. It's an apples-to-oranges comparison that happen to use the same word "tolerance."
> So how exactly would you propose states move forward with allowing people to consume THC and operate vehicles
And that is the conundrum, ain't it? At the very least, the HN crowd is saying "don't take an approach that works well for A but not for B, and apply it to B anyways because it's an easy thing that makes your re-election campaign look like you're doing something instead of having the difficult, nuanced discussion of what IS the right enforcement model for something new."
The risk is these things tend to get cemented in once they're passed. We already did that once with marijuana when we scheduled it more dangerous than methamphetamine, fentanyl, and diazepam. But hey, that scheduling sure did win Nixon the political points he was looking for...
> Other commentators are pointing out and linking to sources that explain how the tolerance bio-mechanisms are very different between alcohol and marijuana. It's an apples-to-oranges comparison.
Yes I've seen that but I have a HARD time believing that two or three beers affects an alcoholic the same as it affects someone who drinks once a month. Alcohol tolerance is also a thing, why are people suggesting it isn't?
> The risk is these things tend to get cemented in once they're passed.
Yes but, it sounds like you have to have some sort of test for this, lest it turns into an "officer discretion" kind of thing since there's no reliable way to measure intoxication. Otherwise, it basically sounds like you can get as high as you want and no one can possibly charge you with DUI because of "you can't prove how long ago I took it" or "I have a tolerance, it doesn't affect me" (which totally does not fly as an argument in court with alcohol).
Alcohol tolerance doesn't meaningfully affect reaction time. We use the same word ("tolerance") for alcohol and marijuana, but the mechanisms are quite different.
Are you suggesting that two people, same weight, same metabolism, but one is a lifelong alcoholic and the other a once-per-month drinker — if they both have three or four drinks, the alcoholic would be just as impaired as the other person? I doubt that. The whole “functioning” part of “functioning alcoholic” implies that the alcoholic is able to, well, function in a manner a normal person wouldn’t if they had been drinking as heavily.
> The whole “functioning” part of “functioning alcoholic” implies that the alcoholic is able to, well, function in a manner a normal person wouldn’t if they had been drinking as heavily.
Well, It's like "functioning" in "high-functioning autism"; it's speaks to how well they can function in society, not how well they can operate a motor vehicle (nor anything to do with reaction times).
> Unlike alcohol for example, there's no clear dose of THC where it can be concluded beyond a reasonable doubt that the person is impaired.
Anecdotally I do think that it's more the case with THC than alcohol, but even with alcohol it's actually not so cut and dry. Two anecdotes from my life:
Me personally - when I learned to drive I was a very heavy drinker. Not "need to drink daily", but I certainly had weeks where I ended every day quite drunk. So when I started driving I bought an expensive personal breathalyser, that the company verifies calibration of before shipping and once per year after that, because while I wasn't looking to get behind the wheel right after drinking I was aware that I often drank enough to still be under the influence the next morning.
I learned that strangely, despite my having a very high tolerance for alcohol back then (like, able to drink a bottle of spirits or a few bottles of wine and still present socially as not impolitely drunk, just enjoyably buzzed), I would feel too drunk to drive before my breathalyser readings showed me above the UK limits. I verified with some disposable tests set at the (even lower) French limits, and I could pass them too while feeling too drunk to be safe driving, after ~5-8 units (a few pints of beer, or half to a whole bottle of wine). If I drank more than that then I would start blowing over the limit, but drinking that amount I would reliably be under the legal limit despite drinking enough that most people would show as way over the limit. I've no idea why, maybe my body is just weird, maybe it's related to how high a tolerance I had (though, like I said, I would be feeling too drunk to feel safe driving even if legal), or what...
Second anecdote is about the husband of a colleague I once had, back before I was a driver myself. I was at their house, we had been drinking together for a few hours, but wanted to get across town for... that's another story. So I said I'll call a taxi, but he claimed to be able to drive safely despite having had 6 or 7 large beers. I assumed it was drunken bravado and insisted no, but then his wife started backing him up and I had a lot of trust in her judgement. As it happens, a week earlier I had been at a televised esports event where all the players had been given a reaction times test using a custom built piece of software, and I had that on my laptop. So I sat him down with it, and fuck me if his reaction times while drunk weren't better than 90% of the professional gamers who'd taken the test. I still felt like I was probably making a stupid decision agreeing to get in the car with him after that, but honestly the journey was about the smoothest drive I've ever witnessed. I'm fairly sure he would have blown way over the limit if tested (unless he was weird like me, back when I knew him was before I learned about my breathalyser results), but if police had seen him drive, or talked to him, they would never have guessed he might be drunk except for the smell of beer on his breath. And it definitely wasn't just me being too drunk to realise he was driving dangerously, a couple more times in the future I got into his car sober while he has been drinking, and felt equally safe each time.
I've no idea what % of people are like me, and can be technically legal on the tests despite feeling too drunk to be safe, or like that man who could be way over the limit yet still drive safer than most sober drivers. But there's at least some people like that! Ultimately the legal limits (which let's not forget, vary from country to country) are a best effort to be a rule of thumb, they're not a perfect indicator of where the safe line is.
Edit to add: I'm sure there are far more people who drunkenly believe they can drive safely despite what they've drunk and are wrong, than there are people like that man who genuinely can drive safely having drunk a fair bit. It's very common for alcohol to give people false confidence, so please don't use my anecdote to justify drunkenly deciding to drive.
Yes, many of us have also taken a college statistical course and understand correlation != causation. Yes, pop-sci articles will more heavily infer there is a causation, and this is bad for public trust in science. Also, dismissing all correlation studies is bad for public trust in science. There's several very good reasons why we do correlation studies, and they actual return interesting data.
I'd like to point out that blood alcohol levels are not 1 to 1 connected to level of impairment, but still serve as a useful indicator for ability to drive. Those with high tolerances behave differently than those with lower tolerances. The current Cannabis test is far from perfect, but seems to be the best proxy we have available for empirical evidence of level of impairment.
There's no methods of field sobriety testing that are actually reliable, what it's best at doing is allowing police to get probable cause even if a sober driver just happens to not be good at something they've not done before and are being asked to do in the dark and cold outside their car in a high stress moment; or, worse, if the police officer judging them is just biased and wanting to subjectively decide they failed.
I'm pretty sure lawyers' advice is generally to say no when asked to take a field sobriety test, as you're basically only asked to do it if the police already think you're going to fail and therefore will be at minimum subconsciously biases towards expecting that. Much better to only let them do any breath/blood tests they can legally insist on. (At least, if you are indeed sober. I don't know what the best advice is if you're going to fail those tests, maybe in that case a tiny chance of being convincing with a field sobriety test is worth the chance?)
Testing for impairment from THC is not as simple as testing for impairment from alcohol.
It's a molecule that is similar to normal endogenous chemicals, and the human body is good at building tolerance to it.
Here is a video (timestamped to the relevant content) of an expert explaining to Huberman why it is so difficult to assess impairment from blood levels.
> I mentally add, "... because we can't even test for it when we pull you over, so... please don't."
Thats not entirely true.
I knew 2 people who loved to drive high. Evidently it feels great (their words, not mine).
Now, being incapacitated or inebriated with any substance is illegal. Even prescription drugs. And basic roadside sobriety tests like "walk in straight line", can be an easy fail if you cant stand up.
Now weirdly, ive never heard of anyone ticketed or pulled for driving sick or very tired. Even though both of those conditions can also be just as dangerous.
The roadside test is basically a test to see if you are a moron dumb enough to consent to it. If you perform an FST good luck doing it in a way that can't be used against you.
In my state you're only required to submit to chemical testing, which the courts have ruled the little portable breathalizer machine isn't, and even if you refuse all they can do is suspend your license and then try to get a warrant.
Given THC lingers in your blood for so long, the inevitable delays in getting the perp to the testing facility won’t help their blood levels fall under the threshold, whatever it is.
Norway used to have a blood alcohol threshold of zero, and if you had any, you were immediately shipped to Ilseng prison, no ifs or buts. Sadly they have abandoned this enlightened policy.
Due to the way weed was legalized in my state, they accidently made THC results ineligible as standalone evidence of intoxication, as ruled by our state's supreme court. If all they have is the THC+ test and no FST they basically have nothing. This from actual appeals case, not just a legal hypothetical.
> The roadside test is basically a test to see if you are a moron dumb enough to consent to it.
Only a moron would not consent to it, lest they lose their license for a year regardless of the outcome of their DUI charge, since it's a separate charge that cannot be fought (you either did the FST or you didn't).
(Of course, every state is different, but I was just matching your matter-of-factness as incorrect-in-general as it was.)
I'm not aware of any state that suspends your license for not doing the FST. Mine only suspends for not doing chemical testing, and the PBT doesn't count (and is inadmissible).
Field sobriety tests are not mandatory in Minnesota, only chemical testing. I’d refuse field sobriety tests every time, they’re subjective. There’s no reason to comply and open yourself up to legal risk in states where it isn’t required.
This is bad advice on a national level. In many states, the best-case scenario if you refuse the FST is that you get a free ride to the police station and have to undergo a blood test.
They couldn't even find a doctor/nurse willing to execute it, and even better like 12 hours of 2 officer's time was wasted (before they gave up, LMAO) trying to execute it so they couldn't hassle anyone else.
No charges, and since I refused to even talk to the police they had nothing.
I'll take getting dragged to the station any day instead of just handing PC to them on a silver platter with some subjective test.
> The roadside test is basically a test to see if you are a moron dumb enough to consent to it.
It's "voluntary" in Germany as well both for alcohol and other drugs, but if you refuse it the cops can and will use every avenue they can to make your life absolutely fucking miserable, and there are a looooot of ways they can abuse.
Especially if you are in the proximity of a highway or important federal road, they can pull off the full "border control checkpoint" under Schengen laws.
Exactly. The test is structured to let the officer use tricks of body language and inference write a police report that makes you seem falling down drunk despite you acing the test.
The roadside tests can be declined with no penalty in my state. So, if I was driving high on THC I’d say “I refuse field sobriety tests but will consent to chemical blood testing, which I am obligated to comply with or lose my driving privileges.”
I’d test positive and then say “Good luck proving I was intoxicated while driving!” and then the DA would refuse to file charges, because there is no way to prove that with THC if you refuse roadside tests.
I was using intentionally vague language to make the point that the study doesn't show us much.
The video I linked is pretty comprehensive. If you skip around, you can find them talking about usage patterns, and how long THC stays in your system, etc.
I am surprised to learn that, thanks! The conditional probability would suggest, if evenly distributed among accidents, to be similar then. So about half of accidents would be included, not the majority
As you can see, and will probably read in upcoming media headlines, the original headline without mentioning that this study was carried out in a single county in Ohio (Montgomery County) is extremely alarmist and even mentioning where they're talking about isn't listed till quite a way down the page.
That isn't to say intoxicated driving isn't a problem. I'm sure that it is (and there may even be data on it I'm unaware of). How to address it without law enforcement having an easy to use immediate test like a breathalyzer for alcohol, I don't know. Driving high/drunk/buzzed on any intoxicating substance is reprehensible and should involve education, public messaging, law enforcement action, and further research into all the aspects of it.
But, headlines like these, IMHO, do more of a disservice than a benefit.
Well, most users drive on it and we know it slows reaction time so it’s easy to believe the headline. Agree bad science is often worse than no science.
> No Effect from Legalization: The rate of drivers who tested positive for THC did not change significantly before or after legalization (42.1% vs. 45.2%), indicating that legal status did not influence the behavior of those who chose to drive after use.
Ohio recently passed a marijuana decriminalization bill.
This would be interesting IFF those drivers did not have alcohol in their system too. I can’t tell if that’s the case from the attached article. I also can’t tell whether the drivers were at fault or e.g. if they froze when another vehicle came at them, which would fit with the stereotype of the slow overly cautious stoned driver vs fast reckless driving you get from alcohol or being a young male (which might be more common in Dayton because of the Air Force base).
Why would anyone expect legalization to cause drug usage to go down? It helps eliminate the violent criminals that proliferate around any criminalized activity. Addicts are not doing drugs for the lure of the forbidden, so making drugs easier and cheaper to get should only increase usage.
Without getting into the technical weeds of dosing, tolerance, and impairment, this is an interesting data set that definitely paints a picture of lax enforcement and ineffective public messaging around substance use and associated impairments. That being said, I also don’t see how we can do better in the USA given that cars are necessary evils for the majority of people outside a select few cities with public transport options, and that we’ve been doing messaging about impaired driving for nearly a century to no real avail.
Perhaps it’s time to start treating motor vehicle operation as an actual privilege rather than a “right” gated by a far-too-easy licensing regime. Start by tasking safety officers with more citations for things like failing to signal or illegal turns through dash camera footage (to avoid dangerous traffic stops), start suspending licenses earlier for consistent or serious infractions, and raise licensing standards higher to shunt more folks onto smaller vehicles or public transit.
This isn’t a cannabis vs alcohol debate despite the framing as such: it’s a debate over how many people should be allowed to drive at all, and to what degree we hold them accountable to ensure good behavior.
while I'm glad they're no longer doing urinalysis and convicted people of DUI based on evidence that doesn't prove anything beyond that they've used marijuana in the past several months, the standard they use to test for impairment (5ng/ml seems to be the highest standard I could find among states that have a standard) may not actually indicate recent marijuana use and in some states the standard for intoxication is so low that frequent users will still test positive after days of abstinence (https://pubmed.ncbi.nlm.nih.gov/32841811/)
This seems fundamentally intended to be misleading. Blood THC concentration has no correlation with current level of impairment the way it does with blood alcohol. "far exceeding most state impairment limits" specifically seems like it was written by someone trying to make a technically correct statement that is essentially wrong. The "legal limit" for THC is either 0 or there isn't one.
It also implies that either the blood was taken within 30 minutes of inhalation or they are measuring something else entirely.
Post mortem diffusion can happen, in either direction. Unless the individual died while smoking, there would have been ample opportunity for the drug to distribute within the bloodstream that could allow post mortem diffusion.
Unless the numbers I have for the blood stream decay rate are completely wrong a number as high as 30.7 seems like an extraordinary claim requiring extraordinary evidence.
I saw a rate of 46% of car crash fatalities are within 30 minutes of the moment of impact. Unless they are only considering the subset of immediate deaths, I would be very sceptical of their numbers.
> Cannabis use in the past year and past month remained at historically high levels for both adult age groups in 2023. Among adults 19 to 30 years old, approximately 42% reported cannabis use in the past year, 29% in the past month, and 10% daily use (use on 20 or more occasions in the past 30 days). Among adults 35 to 50, reports of use reached 29%, 19%, and 8%, respectively.
Have you been to a weed store in a state with legal recreational usage? In my experience, the stores are always busy and you see a wide cross-section of society in line.
This is interesting but the causal relationship inferred by the article isn't supported by the evidence.
Unlike alcohol for example, there's no clear dose of THC where it can be concluded beyond a reasonable doubt that the person is impaired. A dose that might give a regular user a gentle buzz could render a first-time user completely stoned.
It's possible that these people were all incredibly stoned while driving but it's also possible that many drivers in Ohio are regular THC users and have such a high tolerance that their function is unimpaired.
And like always, there's the definite possibility of confounding factors, like reckless drivers also enjoying recreational drug use.
It's also important to note that the article's focus on legal limits is somewhat pointless. As there's no clear threshold above which one is impaired, the legal limits are somewhat arbitrary and are determined by other factors, like whether THC can be reliably tested at the given concentration.
Ultimately, as far as I can tell, the current state of things is that we're fairly certain that THC is able to impair driving ability but we have no idea how much THC is needed to do it or how impaired drivers become.
For a somewhat reputable source, the NHTSA did a report to Congress in 2017: https://www.nhtsa.gov/sites/nhtsa.gov/files/documents/812440...
> A dose that might give a regular user a gentle buzz could render a first-time user completely stoned.
So until we have more research, we legislate to the case of the "first-time user completely stoned," no?
If we’re going to be this cruel it only makes sense to apply the same penalty to using a smartphone while driving, since it results in the same level of reaction time impairment as DWI.
I take issue with calling it "cruel". But yeah we should have really strict penalties on using smartphones while driving.
>So until we have more research, we legislate to the case of the "first-time user completely stoned," no?
Throwing everyone under the bus because of the lowest common denominator is a shitty thing to do when we're talking $10k+ life altering fines here, but your attitude is how everything else involving driving is done so you'll probably get your way even if it's not moral or right.
INB4 people call me a stoner, haven't smoked weed in decades.
Those aren’t the only consequences for DWI
Can you point out where it ‘infers’ a causal relationship? The article as posted only makes the point that the percentage of dead people with THC in their system has remained static despite legalization.
"implies" is probably a better word here
> A dose that might give a regular user a gentle buzz could render a first-time user completely stoned.
> It's possible that these people were all incredibly stoned while driving but it's also possible that many drivers in Ohio are regular THC users and have such a high tolerance that their function is unimpaired.
Can't you make this same argument with alcohol?
> Ultimately, as far as I can tell, the current state of things is that we're fairly certain that THC is able to impair driving ability but we have no idea how much THC is needed to do it or how impaired drivers become.
So how exactly would you propose states move forward with allowing people to consume THC and operate vehicles (or not)? We apparently can't even tell if someone is impaired in a reliable way.
Increased tolerance to THC actually makes it get you less high (for lack of a better term). You need a higher dose to be the same level of impaired. Real stoners can be totally functional and barely even high while hitting a vape every few minutes, but a first-time cannabis user might be on the floor after a single hit.
AFAIK the same isn’t true of alcohol - people who drink a lot may learn to be more functional while drunk, but I don’t believe that someone with a high tolerance has any faster of a reaction time than someone with a low tolerance, if their BACs are the same.
Technically the same thing applies, but to a much, much lesser degree.
While it's true that alcoholics can perform most tasks better than the average person after a few drinks, and there is some data showing they are less likely to get in accidents after drinking, they still become significantly impaired at about the same rate as everyone else. They might have an advantage of a few drinks compared to a regular person, but they often close that gap. The amount of non-impaired alcoholics driving around with BACs above the legal limit is negligible.
The human body's ability to adapt to THC is far greater than its ability to adapt to alcohol. The Endocannabinoid system safely saturates, you can only have so much before the next dose doesn't really do much more. Alcohol, on the other hand, continues to have about the same marginal effect, until toxicity is reached.
> While it's true that alcoholics can perform most tasks better than the average person after a few drinks, and there is some data showing they are less likely to get in accidents after drinking, they still become significantly impaired at about the same rate as everyone else.
This is completely self contradictory. It’s absolutely not “the same rate” if alcoholics can drink multiple additional drinks without showing impairment compared to nonalcoholics.
> They might have an advantage of a few drinks compared to a regular person, but they often close that gap.
This is kind of absurd. “Yeah, they can drink way more without impairment, but they’ll probably still drink to impairment.” This is borderline future crime.
I certainly don’t think we should allow alcoholics to drive with a higher BAC, mostly because the entire point of BAC is to make assessment more objective, but your logic is pretty tortured here.
I'm speaking in comparison to THC. We are talking about order of magnitude differences with THC, especially in the blood after smoking or vaporizing. The difference between a little drunk and very drunk is only a factor of 2, probably less. I don't even think it's possible for a human to be 4 times as drunk as another also drunk human and survive.
The best way to think about tolerance to alcohol is buying a small constant headstart, while THC is better modeled as a difference of rates depending on tolerance. I think most people will find that model useful, and the numbers (BAC) support that as a rule of thumb calculation.
Somehow you disagree that my model is accurate enough, but also agree that a constant cutoff is a good heuristic for legal intoxication from alcohol.
I have no idea about THC tolerance in comparison with alcohol. The numbers I see some people claim to consume is in your order of magnitude range vs what beginners are advised to use so it’s believable.
> Somehow you disagree that my model is accurate enough, but also agree that a constant cutoff is a good heuristic for legal intoxication from alcohol.
It’s not that I think your model isn’t accurate enough. It’s that I think your model is not consistent. A few extra drinks is enough to go from just barely under .08 to .16. If an alcoholic can run nearly double the alcohol intake (and double the BAC) of a nonalcoholic I don’t agree that this is nearly the same.
I agree with the constant cutoff because a constant reasonable limit is easier to administer. Less subjectivity for law enforcement is a good thing. I would probably support for the same for THC. “But I consume so much that I have a really high tolerance!” Ok, that’s not everyone else’s problem to deal with. Don’t drink if you’re over the limit.
> They might have an advantage of a few drinks compared to a regular person, but they often close that gap.
When the legal limit is 0.08 or lower, that's the difference between "too drunk for a non-alcoholic to drive" and "perfectly fine for an alcoholic", isn't it? Yet no court would accept that as an argument.
> Can't you make this same argument with alcohol?
No because a once-daily user of THC will continue to test positive for 14+ days after quitting completely. For alcohol it's 6-12 hours. They are not comparable.
No, I was referring to the argument about tolerance.
"Your honor, my client is a raging alcoholic. Yes he blew 0.2, and while that may make the average person highly intoxicated, my client can function perfectly well at that level."
It is very hard to determine for thc-based intoxication via a test to determine not only when the person was intoxicated, but to what degree. They could have been stoned a week ago, or two weeks ago.
> Can't you make this same argument with alcohol?
Other commentators are pointing out and linking to sources that explain how the tolerance bio-mechanisms are very different between alcohol and marijuana. It's an apples-to-oranges comparison that happen to use the same word "tolerance."
> So how exactly would you propose states move forward with allowing people to consume THC and operate vehicles
And that is the conundrum, ain't it? At the very least, the HN crowd is saying "don't take an approach that works well for A but not for B, and apply it to B anyways because it's an easy thing that makes your re-election campaign look like you're doing something instead of having the difficult, nuanced discussion of what IS the right enforcement model for something new."
The risk is these things tend to get cemented in once they're passed. We already did that once with marijuana when we scheduled it more dangerous than methamphetamine, fentanyl, and diazepam. But hey, that scheduling sure did win Nixon the political points he was looking for...
> Other commentators are pointing out and linking to sources that explain how the tolerance bio-mechanisms are very different between alcohol and marijuana. It's an apples-to-oranges comparison.
Yes I've seen that but I have a HARD time believing that two or three beers affects an alcoholic the same as it affects someone who drinks once a month. Alcohol tolerance is also a thing, why are people suggesting it isn't?
> The risk is these things tend to get cemented in once they're passed.
Yes but, it sounds like you have to have some sort of test for this, lest it turns into an "officer discretion" kind of thing since there's no reliable way to measure intoxication. Otherwise, it basically sounds like you can get as high as you want and no one can possibly charge you with DUI because of "you can't prove how long ago I took it" or "I have a tolerance, it doesn't affect me" (which totally does not fly as an argument in court with alcohol).
Alcohol tolerance doesn't meaningfully affect reaction time. We use the same word ("tolerance") for alcohol and marijuana, but the mechanisms are quite different.
Are you suggesting that two people, same weight, same metabolism, but one is a lifelong alcoholic and the other a once-per-month drinker — if they both have three or four drinks, the alcoholic would be just as impaired as the other person? I doubt that. The whole “functioning” part of “functioning alcoholic” implies that the alcoholic is able to, well, function in a manner a normal person wouldn’t if they had been drinking as heavily.
> The whole “functioning” part of “functioning alcoholic” implies that the alcoholic is able to, well, function in a manner a normal person wouldn’t if they had been drinking as heavily.
Well, It's like "functioning" in "high-functioning autism"; it's speaks to how well they can function in society, not how well they can operate a motor vehicle (nor anything to do with reaction times).
> Unlike alcohol for example, there's no clear dose of THC where it can be concluded beyond a reasonable doubt that the person is impaired.
Anecdotally I do think that it's more the case with THC than alcohol, but even with alcohol it's actually not so cut and dry. Two anecdotes from my life:
Me personally - when I learned to drive I was a very heavy drinker. Not "need to drink daily", but I certainly had weeks where I ended every day quite drunk. So when I started driving I bought an expensive personal breathalyser, that the company verifies calibration of before shipping and once per year after that, because while I wasn't looking to get behind the wheel right after drinking I was aware that I often drank enough to still be under the influence the next morning.
I learned that strangely, despite my having a very high tolerance for alcohol back then (like, able to drink a bottle of spirits or a few bottles of wine and still present socially as not impolitely drunk, just enjoyably buzzed), I would feel too drunk to drive before my breathalyser readings showed me above the UK limits. I verified with some disposable tests set at the (even lower) French limits, and I could pass them too while feeling too drunk to be safe driving, after ~5-8 units (a few pints of beer, or half to a whole bottle of wine). If I drank more than that then I would start blowing over the limit, but drinking that amount I would reliably be under the legal limit despite drinking enough that most people would show as way over the limit. I've no idea why, maybe my body is just weird, maybe it's related to how high a tolerance I had (though, like I said, I would be feeling too drunk to feel safe driving even if legal), or what...
Second anecdote is about the husband of a colleague I once had, back before I was a driver myself. I was at their house, we had been drinking together for a few hours, but wanted to get across town for... that's another story. So I said I'll call a taxi, but he claimed to be able to drive safely despite having had 6 or 7 large beers. I assumed it was drunken bravado and insisted no, but then his wife started backing him up and I had a lot of trust in her judgement. As it happens, a week earlier I had been at a televised esports event where all the players had been given a reaction times test using a custom built piece of software, and I had that on my laptop. So I sat him down with it, and fuck me if his reaction times while drunk weren't better than 90% of the professional gamers who'd taken the test. I still felt like I was probably making a stupid decision agreeing to get in the car with him after that, but honestly the journey was about the smoothest drive I've ever witnessed. I'm fairly sure he would have blown way over the limit if tested (unless he was weird like me, back when I knew him was before I learned about my breathalyser results), but if police had seen him drive, or talked to him, they would never have guessed he might be drunk except for the smell of beer on his breath. And it definitely wasn't just me being too drunk to realise he was driving dangerously, a couple more times in the future I got into his car sober while he has been drinking, and felt equally safe each time.
I've no idea what % of people are like me, and can be technically legal on the tests despite feeling too drunk to be safe, or like that man who could be way over the limit yet still drive safer than most sober drivers. But there's at least some people like that! Ultimately the legal limits (which let's not forget, vary from country to country) are a best effort to be a rule of thumb, they're not a perfect indicator of where the safe line is.
Edit to add: I'm sure there are far more people who drunkenly believe they can drive safely despite what they've drunk and are wrong, than there are people like that man who genuinely can drive safely having drunk a fair bit. It's very common for alcohol to give people false confidence, so please don't use my anecdote to justify drunkenly deciding to drive.
Yes, many of us have also taken a college statistical course and understand correlation != causation. Yes, pop-sci articles will more heavily infer there is a causation, and this is bad for public trust in science. Also, dismissing all correlation studies is bad for public trust in science. There's several very good reasons why we do correlation studies, and they actual return interesting data.
I'd like to point out that blood alcohol levels are not 1 to 1 connected to level of impairment, but still serve as a useful indicator for ability to drive. Those with high tolerances behave differently than those with lower tolerances. The current Cannabis test is far from perfect, but seems to be the best proxy we have available for empirical evidence of level of impairment.
> The current Cannabis test is far from perfect, but seems to be the best proxy we have available for empirical evidence of level of impairment.
Why do we need a "proxy?" What about good ol' field sobriety testing? https://en.wikipedia.org/wiki/Field_sobriety_testing
There's no methods of field sobriety testing that are actually reliable, what it's best at doing is allowing police to get probable cause even if a sober driver just happens to not be good at something they've not done before and are being asked to do in the dark and cold outside their car in a high stress moment; or, worse, if the police officer judging them is just biased and wanting to subjectively decide they failed.
I'm pretty sure lawyers' advice is generally to say no when asked to take a field sobriety test, as you're basically only asked to do it if the police already think you're going to fail and therefore will be at minimum subconsciously biases towards expecting that. Much better to only let them do any breath/blood tests they can legally insist on. (At least, if you are indeed sober. I don't know what the best advice is if you're going to fail those tests, maybe in that case a tiny chance of being convincing with a field sobriety test is worth the chance?)
Testing for impairment from THC is not as simple as testing for impairment from alcohol. It's a molecule that is similar to normal endogenous chemicals, and the human body is good at building tolerance to it.
Here is a video (timestamped to the relevant content) of an expert explaining to Huberman why it is so difficult to assess impairment from blood levels.
https://www.youtube.com/watch?v=jouFvyRZntk&t=6072s
The study in TFA may just be finding that nearly half of drivers in Ohio are habitual cannabis users, or used cannabis in the past few days.
I am always amused when I drive by a PSA billboard in my city that reads, "A little high is too high to drive."
I mentally add, "... because we can't even test for it when we pull you over, so... please don't."
> I mentally add, "... because we can't even test for it when we pull you over, so... please don't."
Thats not entirely true.
I knew 2 people who loved to drive high. Evidently it feels great (their words, not mine).
Now, being incapacitated or inebriated with any substance is illegal. Even prescription drugs. And basic roadside sobriety tests like "walk in straight line", can be an easy fail if you cant stand up.
Now weirdly, ive never heard of anyone ticketed or pulled for driving sick or very tired. Even though both of those conditions can also be just as dangerous.
The roadside test is basically a test to see if you are a moron dumb enough to consent to it. If you perform an FST good luck doing it in a way that can't be used against you.
In my state you're only required to submit to chemical testing, which the courts have ruled the little portable breathalizer machine isn't, and even if you refuse all they can do is suspend your license and then try to get a warrant.
Given THC lingers in your blood for so long, the inevitable delays in getting the perp to the testing facility won’t help their blood levels fall under the threshold, whatever it is.
Norway used to have a blood alcohol threshold of zero, and if you had any, you were immediately shipped to Ilseng prison, no ifs or buts. Sadly they have abandoned this enlightened policy.
Due to the way weed was legalized in my state, they accidently made THC results ineligible as standalone evidence of intoxication, as ruled by our state's supreme court. If all they have is the THC+ test and no FST they basically have nothing. This from actual appeals case, not just a legal hypothetical.
> The roadside test is basically a test to see if you are a moron dumb enough to consent to it.
Only a moron would not consent to it, lest they lose their license for a year regardless of the outcome of their DUI charge, since it's a separate charge that cannot be fought (you either did the FST or you didn't).
(Of course, every state is different, but I was just matching your matter-of-factness as incorrect-in-general as it was.)
I'm not aware of any state that suspends your license for not doing the FST. Mine only suspends for not doing chemical testing, and the PBT doesn't count (and is inadmissible).
Field sobriety tests are not mandatory in Minnesota, only chemical testing. I’d refuse field sobriety tests every time, they’re subjective. There’s no reason to comply and open yourself up to legal risk in states where it isn’t required.
This is bad advice on a national level. In many states, the best-case scenario if you refuse the FST is that you get a free ride to the police station and have to undergo a blood test.
$600 "fuck you fee" on a tow/impound bill vs $6k lawyer. Unless you know you'll blow a zero always take the ride.
I've had a warrant for my bodily fluids before.
They couldn't even find a doctor/nurse willing to execute it, and even better like 12 hours of 2 officer's time was wasted (before they gave up, LMAO) trying to execute it so they couldn't hassle anyone else.
No charges, and since I refused to even talk to the police they had nothing.
I'll take getting dragged to the station any day instead of just handing PC to them on a silver platter with some subjective test.
> The roadside test is basically a test to see if you are a moron dumb enough to consent to it.
It's "voluntary" in Germany as well both for alcohol and other drugs, but if you refuse it the cops can and will use every avenue they can to make your life absolutely fucking miserable, and there are a looooot of ways they can abuse.
Especially if you are in the proximity of a highway or important federal road, they can pull off the full "border control checkpoint" under Schengen laws.
If they are going to use every avenue against you, the FST only gives them more ammo. The test is way more subjective than chemical testing.
Exactly. The test is structured to let the officer use tricks of body language and inference write a police report that makes you seem falling down drunk despite you acing the test.
The roadside tests can be declined with no penalty in my state. So, if I was driving high on THC I’d say “I refuse field sobriety tests but will consent to chemical blood testing, which I am obligated to comply with or lose my driving privileges.”
I’d test positive and then say “Good luck proving I was intoxicated while driving!” and then the DA would refuse to file charges, because there is no way to prove that with THC if you refuse roadside tests.
What's considered habitual? THC notoriously stays detectable in the body for very long time
I was using intentionally vague language to make the point that the study doesn't show us much. The video I linked is pretty comprehensive. If you skip around, you can find them talking about usage patterns, and how long THC stays in your system, etc.
> or used cannabis in the past few days
Two weeks. If used at any time in that past two weeks, THC can show up.
Imagine if we could detect a drink of alcohol two weeks later. Nearly every accident would be classified as having alcohol involved.
> Two weeks. If used at any time in that past two weeks, THC can show up.
It's so much more nuanced than that.
> Nearly every accident would be classified as having alcohol involved.
You might be surprised to know that only something like 50-60% of Americans drink alcohol at all.
I am surprised to learn that, thanks! The conditional probability would suggest, if evenly distributed among accidents, to be similar then. So about half of accidents would be included, not the majority
And a minority of drinker drinks the bulk of it.
> 10% of drinkers consume over half of all alcohol consumed in Australia
https://www.ias.org.uk/2024/01/23/10-of-drinkers-consume-ove...
As you can see, and will probably read in upcoming media headlines, the original headline without mentioning that this study was carried out in a single county in Ohio (Montgomery County) is extremely alarmist and even mentioning where they're talking about isn't listed till quite a way down the page.
That isn't to say intoxicated driving isn't a problem. I'm sure that it is (and there may even be data on it I'm unaware of). How to address it without law enforcement having an easy to use immediate test like a breathalyzer for alcohol, I don't know. Driving high/drunk/buzzed on any intoxicating substance is reprehensible and should involve education, public messaging, law enforcement action, and further research into all the aspects of it.
But, headlines like these, IMHO, do more of a disservice than a benefit.
Well, most users drive on it and we know it slows reaction time so it’s easy to believe the headline. Agree bad science is often worse than no science.
they grow cherries in montgomery county? they certainly like to pick cherries there.
> No Effect from Legalization: The rate of drivers who tested positive for THC did not change significantly before or after legalization (42.1% vs. 45.2%), indicating that legal status did not influence the behavior of those who chose to drive after use.
Ohio recently passed a marijuana decriminalization bill.
Some people have hinted at the following point but I wanted to ask directly:
How many recently dead Ohio adults have THC in their blood? Forget driving.
This would be interesting IFF those drivers did not have alcohol in their system too. I can’t tell if that’s the case from the attached article. I also can’t tell whether the drivers were at fault or e.g. if they froze when another vehicle came at them, which would fit with the stereotype of the slow overly cautious stoned driver vs fast reckless driving you get from alcohol or being a young male (which might be more common in Dayton because of the Air Force base).
How many drivers killed in crashes had accessible phones in their vehicles? I bet it was more than half.
Why would anyone expect legalization to cause drug usage to go down? It helps eliminate the violent criminals that proliferate around any criminalized activity. Addicts are not doing drugs for the lure of the forbidden, so making drugs easier and cheaper to get should only increase usage.
The article doesn't mention what percentage had alcohol, with and without THC. Why not?
Without getting into the technical weeds of dosing, tolerance, and impairment, this is an interesting data set that definitely paints a picture of lax enforcement and ineffective public messaging around substance use and associated impairments. That being said, I also don’t see how we can do better in the USA given that cars are necessary evils for the majority of people outside a select few cities with public transport options, and that we’ve been doing messaging about impaired driving for nearly a century to no real avail.
Perhaps it’s time to start treating motor vehicle operation as an actual privilege rather than a “right” gated by a far-too-easy licensing regime. Start by tasking safety officers with more citations for things like failing to signal or illegal turns through dash camera footage (to avoid dangerous traffic stops), start suspending licenses earlier for consistent or serious infractions, and raise licensing standards higher to shunt more folks onto smaller vehicles or public transit.
This isn’t a cannabis vs alcohol debate despite the framing as such: it’s a debate over how many people should be allowed to drive at all, and to what degree we hold them accountable to ensure good behavior.
We need self driving cars and VR so people can get high with their friends without having to drive
There are Uber, taxi and other public transportation. You can get high with your friends and don't drive. Just plan ahead.
What else is there to do in Dayton?
in other news, half of Ohio county not dead in auto crashes, also test positive of THC
Tell people not to drive unless it's vital and to take public transit whenever possible.
The fact is that people are bad at estimating risks so they need to be told the facts.
> Tell people not to drive unless it's vital and to take public transit whenever possible.
That sounds like a miserable way to get around. Driving is the bees knees.
Driving is a tragic waste of human attention.
while I'm glad they're no longer doing urinalysis and convicted people of DUI based on evidence that doesn't prove anything beyond that they've used marijuana in the past several months, the standard they use to test for impairment (5ng/ml seems to be the highest standard I could find among states that have a standard) may not actually indicate recent marijuana use and in some states the standard for intoxication is so low that frequent users will still test positive after days of abstinence (https://pubmed.ncbi.nlm.nih.gov/32841811/)
Really? What else did they have in their blood?
This seems fundamentally intended to be misleading. Blood THC concentration has no correlation with current level of impairment the way it does with blood alcohol. "far exceeding most state impairment limits" specifically seems like it was written by someone trying to make a technically correct statement that is essentially wrong. The "legal limit" for THC is either 0 or there isn't one.
Even if there was such a limit, people who use cannabis for medical reasons would have to be exempt.
Correlation is not causation. I think the writer fails to make the case.
This literally means nothing. Do you know how long THC lasts in your blood after smoking?
The article mentions 30.7 ng/mL which is a level that implies consumption within an hour.
It also implies that either the blood was taken within 30 minutes of inhalation or they are measuring something else entirely.
Post mortem diffusion can happen, in either direction. Unless the individual died while smoking, there would have been ample opportunity for the drug to distribute within the bloodstream that could allow post mortem diffusion.
Unless the numbers I have for the blood stream decay rate are completely wrong a number as high as 30.7 seems like an extraordinary claim requiring extraordinary evidence.
I saw a rate of 46% of car crash fatalities are within 30 minutes of the moment of impact. Unless they are only considering the subset of immediate deaths, I would be very sceptical of their numbers.
it doesn't imply that. how did you come up with "within an hour" stuff?
It means a lot give how small a percentage of people even touch THC with a 10-foot pole.
According to this, 16.5% of Ohio residents used a marijuana product in the last year in 2023: https://www.statista.com/statistics/723822/cannabis-use-with...
Hard to argue that's a small percentage.
without knowing the methods of that survey, if that 16.5% was self-reported you can expect that the actual number is even higher
> Cannabis use in the past year and past month remained at historically high levels for both adult age groups in 2023. Among adults 19 to 30 years old, approximately 42% reported cannabis use in the past year, 29% in the past month, and 10% daily use (use on 20 or more occasions in the past 30 days). Among adults 35 to 50, reports of use reached 29%, 19%, and 8%, respectively.
https://nida.nih.gov/news-events/news-releases/2024/08/canna...
42% of 18-30 year old Americans have used THC within the last 12 months. That's pretty much the exact same figure as the number in the article.
This basically means it’s road and vehicle safety that is causing people to have fatal accidents, not THC in their blood.
Have you been to a weed store in a state with legal recreational usage? In my experience, the stores are always busy and you see a wide cross-section of society in line.
Half of Americans have tried pot at least once: https://news.gallup.com/poll/509399/fully-half-americans-tri...