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Over 40% of Deceased Drivers in Vehicle Crashes Test Positive for THC: Study

epistasis

Based on the headline, I was guessing it was any amount of positivity, and may be close to the population level, but it's actually impairment levels of THC:

> In a review of 246 deceased drivers, 41.9% tested positive for active THC in their blood, with an average level of 30.7 ng/mL — far exceeding most state impairment limits.

Since COVID in CA, it feels like driving has become far more dangerous with much more lawlessness regarding excessive speeding and running red lights, going into the left lane to turn right in front of stopped cars, all sorts of weird things. But I can't tell if my anecdotes are significant. It seems that Ohio's impaired drivers have been consistent through the past six years though.

Benjammer

>Since COVID in CA, it feels like driving has become far more dangerous with much more lawlessness regarding excessive speeding and running red lights, going into the left lane to turn right in front of stopped cars, all sorts of weird things

NYC has had the same effect since COVID, and over the last year or two it's gotten to the point where every single light at every busy intersection in Manhattan you get 2-3 cars speeding through the red light right after it turns. I bike ride a lot so I'm looking around at drivers a lot, and for the most part the crazy drivers seem to be private citizens in personal cars, not Uber or commercial/industrial drivers.

macNchz

It’s a very widespread problem, I think, and probably has a complex mix of causes, but my perception as a NYC runner, cyclist, and driver is that there’s a fairly small percentage of extremely antisocial drivers who we allow to behave badly with relative impunity, which itself moves the Overton window of driving behavior towards aggression/chaos, so to speak.

Very frequently when there is a newsmaking incident in which a driver runs people over in some egregious fashion, it turns out that they got dozens of speed camera tickets per year. We know who these people are, we just don’t seem to have any motivation to actually do anything about it.

The city has published research on this, showing drivers who get 30+ speed camera tickets in a year are 50x as likely to be involved in crashes with serious injuries or death, but efforts to actually do something about their behavior are consistently stalled or watered down. Other research points to various causes, including backed up courts and decreased enforcement generally.

https://www.nyc.gov/html/dot/html/pr2025/nyc-dot-advocate-fo...

https://www.nyc.gov/html/dot/downloads/pdf/nyc-driver-behavi...

spamizbad

Yeah I feel like the United States could dramatically improve its road safety if it kept maybe 1-3% of its drivers off the road permanently.

carlmr

>it turns out that they got dozens of speed camera tickets per year

To me the answer is quite simple for any of these. Treat repeated small infractions like bigger and bigger infractions. E.g. double the cost every iteration if it happens within a specific time frame.

Ok, you speed once? $100. Twice $200. Thrice $400. And so on. We only reset if you don’t reoffend for any speeding in 5 years. If you want to speed 20 times in 5 years, ok, go ahead. You pay $52,428,800.

Bonus points for making it start at something relative to your salary. People will stop at some point out of self-preservation.

If you don’t believe high fines work, drive from Switzerland to Germany. In Germany the Swiss have no problem speeding, because the fines are laughable. While south of the border they behave very nicely on the street.

You could extend this to other crimes. Google and Microsoft happily pay fines, since it’s cheaper than what they make from breaking anti-trust regulations. If you doubled it on each infraction they would at some time start feeling the pain.

temp0826

What the heck? How can you get that many tickets and still have a license? (Or manageable insurance costs for that matter lol)

master_crab

I haven’t seen driving behavior change in NYC over the past two decades.

Also, NYC has a different driving attitude than, say, Dallas. What people call aggression is often a difference in expectations. Drivers change lanes and merge far more assertively than in other parts of the country. As long as you aren’t causing the car behind you to panic brake, it’s considered acceptable. Hesitation from drivers tends to get more opprobrium than tight merges.

People block bike lanes and the box all the time. It’s annoying and you shouldn’t do it. But a lot of the rage is often unjustified. That FedEx truck needs to park somewhere and they aren’t going to roll over a fruit stand to do it.

It’s a dense, packed city. If you can’t give and take, you are going to hate it here.

woodruffw

I’ve lived here my entire life, and there’s a significant difference between being a normal “aggressive” driving and many of the driving patterns that have emerged post-COVID. For example: blocking the box is (unfortunately) somewhat normal, while running through red lights and making illegal turns has (anecdotally) increased significantly.

Benjammer

It what way is speeding through red lights "a give and take thing"??? I never mentioned blocking the box or illegal parking, I'm not sure where you got that from.

bluGill

Traffic safety engineers do not agree with all of those things. don't be an agressive driver even if everyone else is.

nothrabannosir

Funny I ride a bike in Manhattan & BK (but only post COVID) and I very rarely experience cars going through reds. IME cars here respect traffic lights and stop signs. I try and count cars actually running a red ("speeding" through it) and it's rare, say 1/mo tops. Ymv I guess :)

They do not, though, give an owl's hoot about yielding to straight traffic when turning. I suspect NY drivers are on a big group chat encouraging each other to cut off cyclists and pedestrians, by turning into their lane whenever they see one, and promptly parking there for an hour.

And there's the "squeeze", and "crowding the box". Almost like no car here is truly allowed to ever really stop so they're always gently rolling, just a little, juuuuust a little, just, maybe, I know it's red but maybe just a lil squeeze into the intersection, maybe, squeeze, ...

I don't know how to explain it but if you've been here you'll recognize it I'm sure.

VerifiedReports

The worst are assholes "blocking the box" while there is space to pull forward along the curb or even the neighboring lane. This should be a tripled fine, simply for the monumental level of douchebaggery displayed.

SecretDreams

Could we verify this against data? Surely if people are trying way worse post covid, that would show up compared to pre covid data by way of accident, fatality, and ticket issuances, e.g.?

To the OP, I'm not sure I buy into it being tied to THC which seems to be the implication. Canada isn't seeing this trend, afaik.

epistasis

Those who are autopsied due to traffic deaths clearly show a massive amount of THC impairment.

But the data here also show that it's a consistent level before and after legalization of cannabis in Ohio. So legalization of cannabis in Ohio did not cause a big increase in impairment-levels of THC in those who died in traffic.

bko

I think it's lawlessness overall. For instance, consider San Fransisco traffic citations. Went from around 11k in 2014-2015 steadily down and then fell off a cliff during covid but never recovered (around 1k in 2023).

I remember the sad story of Eric Garner who was killed in 2014 while being arrested for selling loose cigarettes in Staten Island. Today, at least in NYC, you see people parked out in front of the same corner every day selling weed and loose cigarettes. Same people, out in the open. I'm pretty sure that's not a sanctioned dispensary.

Just shows how much things can change in ten years. For whatever reason, police and prosecutors just gave up in enforcing any kind of laws. Seems like an overreaction to whatever problems we had with criminal justice

https://www.reddit.com/r/sanfrancisco/comments/11nbnxw/san_f...

https://en.wikipedia.org/wiki/Killing_of_Michael_Brown

roughly

I think it’s underappreciated the degree to which police and LEO have started behaving like political actors. NYC cops decided to “strike on the job” when the city started changing its stance in the mid-2010s, and in the Bay the cops responded similarly to Prop 47 by effectively not prosecuting shoplifting and other minor crimes anymore. Similarly, the recall of Pamela Price started almost the moment she took office and was accompanied by a work slowdown by the OPD in the interest of making the crime situation look worse. There’s other examples, but effectively the police have turned lax enforcement into a tool to preclude any shifts in policing policies. I’ve got my own feelings about those policies, but when you’ve got the cops acting like a political block that gets to set policies instead of a group of city employees tasked with enforcing them, I think that should concern the rest of us.

bko

There's probably some of this, but I think it's driven by district attorney not prosecuting people. We see people that have 20+ prior arrests. How many times can a cop arrest the same person and do the paperwork if he's not going to be prosecuted? I don't think people are pushing police to arrest more people.

> Nearly a third of all shoplifting arrests in New York City last year involved just 327 people, the police said. Collectively, they were arrested and rearrested more than 6,000 times, Police Commissioner Keechant Sewell said. Some engage in shoplifting as a trade, while others are driven by addiction or mental illness; the police did not identify the 327 people in the analysis.

Not clear if that's only in 1 year, but 6,000 arrests for the same 327 people means 18 arrests per person on average. Maybe if you see the same person shoplifting more than 5 times you put him away for some real time. 10 times? Hell even 20 strikes and you're out would make a real dent and serve as a deterrent.

https://archive.is/VCKkk#selection-473.0-473.379

epistasis

It's not entirely new! In 1975 during labor negotiations the police detonated a bomb on the mayor's yard, partially damaging the front door, and left a note saying "Don't threaten us":

https://cdnc.ucr.edu/?a=d&d=DS19750820.2.20

Since then, the SFPF have always had a culture of being above the law. The monopoly on legal violence thing can be taken a bit too far.

antonymoose

I do believe you’re mixing up Michael Brown in Missouri who robbed a gas station and assaulted a cop and attempted to steal his pistol (per your own link) with Eric Garner in New York who was choked out by a police officer and subsequently died.

bko

Yes, I am. Updated. Thank you

nomel

https://www.nationalacademies.org/news/to-reduce-racial-ineq...

Are there any stats for incorrect crime reporting based on political leaning?

null

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HarHarVeryFunny

The numbers do appear quite staggering. It can't just be the dead drivers - there must be similar numbers of stoned drivers who are causing accidents, maybe killing others, while surviving themselves.

As far as driving goes, any amount of drugs or alchohol is going to reduce reactions times, in addition to any impaired judgement or ability to control the vehicle. Even a couple of 1/10ths of a second in increased reaction time is enough to make the difference between braking in time and hitting another car or pedestrian/etc.

gretch

The running red lights thing is crazy. I think at it's height, I would maybe see 3 people do this in a single 20 minute drive.

And not like running a late yellow, but a full on my-light-is-green-and-there's-a-guy-in-front-of-me-sideways

It has dropped a bit now though.

dawnerd

I was tboned by someone that swore their light was green. I had a dedicated turn. Thank goodness for cameras.

The trend I’ve noticed this year is turning right from the middle lane cutting off people in the turn lane.

VerifiedReports

Are they cutting them off, though? If the street you're turning onto has two lanes, it shouldn't be a problem for two cars to turn at once. The car on the inside is required to turn into the nearest lane (according to any state law I know), so why can't the car on its left turn into its own lane?

tiltowait

Traffic fatalities increased during the pandemic[1]. AAA released a study examining the effects in 2024[2].

[1]: https://pmc.ncbi.nlm.nih.gov/articles/PMC10149345/ [2]: https://newsroom.aaa.com/2024/08/the-pandemics-tenacious-gri...

swimorsinka

We've seen the same uptick in reckless driving in CO since Covid. Reddit Denver complains about it all the time. I think it's happening everywhere, and it's not clear why.

y-c-o-m-b

Before this year I had only seen 1 wrong way driver in 30 years. In the last year alone I've seen 6! I saw one person going the wrong direction in a round-about. Another person going over the inner portion of a round-about. People stopping in the road for no reason. It's insane. The strange driving patterns is indeed a major issue. I thought it was maybe a Gen Z thing, but often times these people seem to be between 30-50 in age.

Edit: no offense to Gen Z with my earlier comment btw. My reasoning was maybe we're failing younger generations with drivers ed so the blame would be on us anyway.

Also I've seen these strange patterns in many states in the last year+: Oregon, Washington, Wyoming, Idaho, California

zoklet-enjoyer

Come to Fargo. I see it multiple times a year. Usually right after a new semester starts and the farm kids don't know about one ways haha

darubedarob

Its usually drivers license transfers from countries where small bribes can "buy" you a license? https://wise.com/us/blog/transfer-international-driver-licen...

The worst offenders are usually the older generations of countries where driving en mass is a recent thing. The old red guard uncles and aunties regularly run red lights cause who gives a damn about the law when you experienced the rule of the mob throughout your formative years. So parents and grandparents of students would be my guess.

y-c-o-m-b

I'm not talking about one-ways, those are confusing in general. I'm talking about clearly marked off-ramps from freeways. In one situation the person had to drive over a fairly large bump in the median just to enter the wrong side of the freeway; again many signs to prevent such a thing and they still ended up in that predicament. Sometimes miles down the freeway before a cop pulls them over. It's terrifying.

I saw another one where the car tried to turn right into an off-ramp with a line of cars waiting at the light. Like wtf, do you not see the wall of cars and headlights in front of you? Where are you going?!

elif

It is crucial to consider correlated variables in their correct context. This finding does not even imply impairment.

A low emotional intelligence driver, one with depression or low self worth, perhaps a psychological pathology like narcissism or nihilism. This is the type of person to initiate vehicular homicide. Intoxicant intake is a SUBSET of this group of variables.

The archetypical homicidal driver would of course have exceptionally high representation in cannabis use, and also likely cigarette use, and probably nitrous oxide but they don't measure that.

EDIT: what I will say is that dab culture is something beyond traditional cannabis use, and I could absolutely theorize that dab use in a vehicle is the new drunk driving.

tokai

An issue with having the legal limit at ~2-5ng/ml is that it makes habitual users be over the limit if they have smoked recently or not.[0] Making the prohibition seem unserious to some, not about safety but about punitive control, and in turn making it matter less if you smoke and drive as you are taking the risk of getting into trouble in any case.

The impairments of driving under the influence of alcohol have been extensively studied, but unless I have overlooked the literature it seems that the same investigations have not been carried out with THC.

[0] «Blood THC >2 ng/mL, and possibly even THC >5 ng/mL, does not necessarily represent recent use of cannabis in frequent cannabis users.»; https://www.sciencedirect.com/science/article/abs/pii/S03768...

Youden

There was a larger discussion in a previous thread on this topic: https://news.ycombinator.com/item?id=45494730

Since then, [0] has been published and I think it's worth at least a skim. Since it's quite recent the introduction summarizes some of the most recent research.

The things that jump out at me are:

- [0]: Habitual users with baseline concentrations above legal limits perform just as well as habitual users with baseline concentrations below the legal limit, indicating that for habitual users, the legal limit doesn't have any relation to impairement.

- [1]: A study in Canada analyzed crash reports and blood tests to look at the state of drivers responsible for accidents. While alcohol had a very clear and statistically-significant influence on the risk of a driver causing an accident, THC did not.

To steelman the idea that THC causes accidents, [0] only looks at habitual users with baseline levels of THC and [1] only looks at non-fatal injuries.

My conclusion right now is that the number of drivers in accidents with THC in their blood is going up because the number of people with THC in their blood is going up, not because drivers who use THC cause accidents.

The law's assumption that this level of THC is evidence of impairment seems to be invalid.

The law would be better off measuring impairment in some way and perhaps intensifying penalties when an impairment test fails and the user has THC concentration above some threshold.

[0]: https://academic.oup.com/clinchem/article/71/12/1225/8299832...

[1]: https://pubmed.ncbi.nlm.nih.gov/31106494/

seizethecheese

Sure, but in this study 40% of people had very high THC concentrations. Is it even remotely plausible this is the baseline population level?

terminalshort

But the truth is that habitual users are always impaired. Source: former habitual user.

Sparkle-san

Got any real sources? I've been a daily user for over 10 years and also have a spotless driving record.

Aurornis

> I've been a daily user for over 10 years and also have a spotless driving record.

I knew a guy who drove home from bars unquestionably over the legal limit (example: 4-5 drinks in 90 minutes) every single weekend for years without getting caught or getting in accident.

It doesn’t mean he wasn’t impaired.

n8cpdx

It depends on the level of your habitual use. A 5mg gummy every evening is probably fine.

I’ve seen plenty of people who are essentially using THC vapes like nicotine vapes, in that they use them every few hours and start to get anxious if they don’t. Stoned driving has become normalized - between seeing people lighting up behind the wheel on snap map, seeing it on TV (this happened in The Rehearsal season 1), and seeing it in person, it would take a lot to convince me otherwise.

If you’re high all day every day, that may be your normal, but it doesn’t mean you’re competent to drive.

In my personal experience, it took a very long time to fully get through a high dose of THC - usually at least a full night sleep, but sometimes more like two, before my reaction times came back. Notably, it takes much longer for the impairment of THC to wear off than the subjectively enjoyable experience of being high, so you can “sober up” but still be impaired.

If you’ve been getting high every day for 10 years, it is hard to take seriously that you would know if you’re impaired. Kind of like vegans who haven’t tasted dairy for 10 years tend not to be reliable judges of the quality of vegan mayo - how could they possibly know?

markeroon

If we're doing anecdotes I'm sure there are lots of drunk drivers with spotless records.

I understand that you're taking issue with the idea of always being impaired, but the article indicates that there's a pretty clear association between having ingested THC and being in a car crash.

formerly_proven

It is very noticeable to basically everyone when you consume cannabis regularly.

walletdrainer

Sure, but the problem isn’t whether or not a driver is impaired, but the degree to which they are impaired.

mrj

Well, it would be good for the rest of us on the road if people driving two tons of murder box are 0% impaired.

I'm no angel but I have gotten more diligent... I'm just reacting to "the degree". The goal has to be zero degrees of impairment when a moment of inattention can kill.

Also, my son was just hit by a driver while he was on a bike and in the bike lane. They claimed not to see him. He's fine thankfully but it's really scary to watch him ride off.

marcinpieczka

That works the same with alcohol - heavy alcoholic would probably need to be over the limit to feel ok and sober.

shtzvhdx

[dead]

iLoveOncall

Opening the article would have allowed you to see that the average was 30.7 ng/mL, it's in the very first bullet point!

tokai

If you calmed down and stopped snapping at everyone, you might understand that I'm writing about how the law and a lack of studies could make some people more willing to drive high. You are substantially diminishing the quality of the discussion here.

dragonwriter

The average (presumably arithmetic mean, though it could technically be any of a wide variety of measures) is not particulatly interesting, the median specifically would be more interesting, as a single figure.

adgjlsfhk1

using a mean rather than median is fairly odd here. a mean is pretty much worthless without knowing distribution shape.

Someone

> In a review of 246 deceased drivers, 41.9% tested positive for active THC in their blood, with an average level of 30.7 ng/mL — far exceeding most state impairment limits.

That could mean they all had levels far exceeding most state impairment limits, but it also could mean most of them had trace levels, while a few had levels way above 30.7 ng/mL. So, it says fairly little.

Also (FTA) “Researchers analyzed coroner records from Montgomery County in Ohio from January 2019 to September 2024, focusing on 246 deceased drivers who were tested for THC following a fatal crash”. That means there could be selection bias at play.

Finally, no mention is made on the levels of THC in the general population of of those driving cars. Both _could_ be equal or even higher.

I’m not sure one should blame (only) the researchers for these statements, though. Chances are they didn’t intend to find out whether THC use is a major cause of vehicle crashes, but only in whether legalizing THC use changed those numbers, and someone managed to get some more juicy quotes from them.

thrill

“Finally, no mention is made on the levels of THC in the general population of those driving cars.”

How do you propose gathering that particular data?

flufluflufluffy

Came here to say most of this, also worth calling out the note at the bottom:

> Note: This research was presented as an abstract at the ACS Clinical Congress Scientific Forum. Research abstracts presented at the ACS Clinical Congress Scientific Forum are reviewed and selected by a program committee but are not yet peer reviewed.

My guess is when it gets to peer review, one of the reviewers will request at least mentioning these limitations. As it was only an abstract, it’s possible the paper itself does mention these limitations already as well.

3eb7988a1663

Wish the paper were available - would love to know the percentage with alcohol.

The other question I have - my prior is that a bad driver (tired, drunk, high) is something like 70:30 odds of killing themselves vs some innocent bystander dying because of their actions. I have anecdotally heard of several sad tales where some guy is on his Nth DUI and kills an entire family, while he walks away from the accident without a scratch. Meaning are the rates of fatalities involving THC actually higher, but the detectably inebriated person managed to walk away without dying.

jjice

Feels like a low sample size, but I'm not statistician or doctor.

That said, almost everyone I know that consumes THC has no qualms driving while doing it, and many of them also at work. It's a huge peeve of mine.

losteric

Wow, pretty much no one I know drives under any influence regardless what they use.

I wonder how many of these people were under the influence of alcohol and other substances.

DontchaKnowit

There is a very common sentiment among weed users that it doesnt really count as far as driving goes. Stoners will be repulsed and outraged by drunk drivers and then think nothing about going for a "blunt ride"

seizethecheese

My friend group in college were heavy weed users, and generally all of them drove while high. I remember one saying he enjoyed it because he felt like he was driving a space ship. I asked if he still thought it was safe to drive, given that impression, and he said yes.

zoklet-enjoyer

I drove high a few times when I was younger and I had to set my cruise control to 25mph to make sure I was going fast enough haha never again. I just use before bed now or occasionally during the day if I know I won't have to drive anywhere.

null

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SecretDreams

Even though their sentiment is wrong, I get why they would feel that way. Marginally drunk vs marginally high certainly feel* very different in how they would impact my own ability to drive.

That said, I don't do either. I also wouldn't take any amount of weed while working, but I'd feel comfortable having a beer during lunch if appropriate (work lunch/celebrate, e.g.).

sa-code

The number of times I've heard "I'm good" honestly breaks my heart. Only to have people call me "Hermoine" etc (I am a straight cis man). I wonder what's the best way to talk about this

dragonwriter

> Feels like a low sample size

Its not a sample, it is the whole universe of analysis. (If you treat it as a sample of, say, US drivers killed in accidents in the same period, then errors due to sample size are probably the least of its problems.)

moefh

We don't know that. We don't even know if there's selection bias.

The article says the research was "focusing on 246 deceased drivers who were tested for THC", and that the test usually happens when autopsies are performed. It doesn't say if autopsies are performed for all driver deaths, and it also doesn't say what exactly is "usually".

If (for example) autopsy only happens when the driver is suspected of drug use, then there's a clear selection bias.

Note that this doesn't mean the study is useless: they were able to see that legalization of cannabis didn't have impact on recreational use.

teddy-smith

Whenever you think to yourself "People couldnt be that stupid, right?" read this study and plan accordingly.

neoCrimeLabs

I am curious what percentge of the general populous test positive for THC. It would give better context to a dead drivers testing positive for THC.

tasty_freeze

I don't think it is that simple. I would wager $$$ that dead drivers tend to skew younger, mostly young men who think they are great drivers, drive way too fast, pass with little margin, etc. Young people probably skew higher for THC use as well.

Having said that, I think that effect explains only part of the 40%, but can't explain all of it.

iLoveOncall

> It would give better context to a dead drivers testing positive for THC.

No it wouldn't.

People make those excuses because it's weed, but you would have never posted that on an article about alcohol.

fn-mote

No need to be judgmental about statistics. They are just facts.

A similar result about alcohol would be the (hypothetical) statement that the rate of drunk drivers in fatal accidents was constant before and after the enactment of Prohibition.

I do agree that the fact that fatal THC% stays constant before and after legalization is a surprise.

neoCrimeLabs

Wasn't so much looking for an excuse, so much as more information.

Why did you automatically assume the point of bias?

SecretDreams

Yes, it would be useful. When controlling for variables, you normally want to compare against a baseline.

If 40% of the whole population has THC in them, we'd need a control population (maybe from earlier when thc was less prominent) to see if per capita deaths has meaningfully increased. I'd do the same study, tangentially, for tech workers to see if productivity has changed when controlling for other variables.

watwut

It absolutely would. If 40% of people test positive for THC, then this would mean there is no effect. I find it unlikely 40% of people test positive for THC, but yes, it does matter.

gpm

That wouldn't actually mean no effect, you need 40% of people driving to test positive for it to be no effect. It's unlikely the population driving is equivalent to the population at large - for one there's a set of responsible people who won't drive while high. For another weed use isn't randomly distributed through the population but correlated with certain subsets, which probably have a non-average rate of driving just by coincidence.

(Not that it really matters since I don't buy for a second that anywhere near 40% of people/people-driving are high at any given time. I also don't put much faith in numbers in the abstract of a a yet-to-be-published study...)

Chris2048

> If 40% of people test positive for THC, then this would mean there is no effect

Can you explain what you mean by this?

xienze

The article is not saying 40% of all drivers tested positive, it’s stating that 40% of people who died in a car accident tested positive, at pretty high levels too.

root_axis

> you would have never posted that on an article about alcohol

Well of course not, as the two drugs have completely different intoxication side effects.

epistasis

> “An average level of 30.7 ng/mL generally means those people must have consumed marijuana at some time close to driving. This isn’t about residual use; it’s about recent consumption.”

If we are at 40% of the population being high at any given moment I think we are having extremely serious societal problems around mental health. Occasional use is not a big deal IMHO, but if a person is spending 40% of waking hours impaired that person has some serious unmet psychological needs.

fn-mote

This reading doesn’t make sense. There’s no way to extrapolate from this to any statement about 40% of the population, and even 40% of the day is a serious misread imo.

epistasis

I'm replying to a comment suggesting that this data may be close to population levels rather than something different in the autopsy population.

I'm arguing that if the population data looks anything like the autopsy data, it would imply a massive epidemic of THC overuse.

bobro

One useful point of comparison here would be the percent of the driving population overall who have some THC in their system in the same way as these researchers are measuring it. I wouldn’t guess that 40% of drivers would test positive for recent THC use, but I can’t understand the 40% number here without knowing the percent for the overall population.

leke

My question is, what is the difference in vehicle death mortality since cannabis was legalized in those parts of the country. If it's about the same, it just tells me that cannabis is a very popular drug.

null

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8organicbits

The lack of change after legalization of recreational use is interesting. How many deaths related to medical use versus (previously illegal but decriminalized) recreational use?

loeg

I don't think the user population changes much whether it's illegal, "medical," or legal.