I’m not surprised so many deceased drivers were under the influence of THC. I see people smoking and vaping at stoplights all the time. I am however, surprised this study claims legalization didn’t change the rate. Anecdotally, on the west coast, I’ve seen far more of this, and also people casually smoking in public spaces (parks or train stations or whatever) since legalization.
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.
Non-scientific anecdote here but I feel like the lawlessness is due to lack of enforcement for traffic violations vs an uptick in weed usage. Possibly covid scrambled our brains and promotes aggressive impulsive behavior. Maybe cops are afraid to pull people over because they might inadvertently shoot them and become a national news story. Maybe the adoption of big trucks makes people feel invincible (two distinct trucks on my drive have cut in line at a left turn lane with a red arrow and crossed 2 lanes opposing traffic at different lights, what would possess someone to do that(?))
Whatever the cause I feel in my gut that if our police did basic standards enforcement people would think twice about lawlessness. I’m in Pennsylvania.
I got a dog during COVID and I'm not sure if this is a related issue but the number of times I've had people not brake but accelerate as we're crossing the street or flash their high beams or try to drive around us at the last moment is insane.
there are days where it happens multiple times during one walk and weeks where it happens at least each day of the week.
i'm actually a car guy but when i drive if i see any pedestrians i always slow down and i take it even easier if i see they have small children or dogs since either can randomly stop or dart away.
If you have ever driven in Ohio the driving behavior is absurdly different than what you see in places like CA. People rarely speed. They willingly let you cut them off. And there are reasons for that too. Here is a map of where you are most likely to get a speeding ticket (1). The only place in california I've seen any enforcement of speeding or traffic behavior is along the 395 corridor in the Owens valley. Incidentally this region comes up in the map. It simply does not happen in LA county at least. Well, maybe they slap a speed ticket onto a pursuit case on top of everything else. But no sit and wait radar taking that I've seen.
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.
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.
This feels like we’re missing a dimension or threeve, the one that comes to mind immediately would be whether or not the deceased driver was at fault for the incident.
Just noting there’s a difference between THC in your system and THC in your blood. THC leaves the bloodstream after your high. Goes into fat cells and other areas to be broken down and processed (up to a month) later. Having it in the bloodstream after an accident means they were intoxicated at the time according to science. Whether their CB1 receptors were letting it through is another matter. I can smoke a lot of weed and not “feel high” yet I would test off the charts on this test.
For drunk drivers it’s rather easy to assess whether someone is impaired. With marijuana it’s not. So until we have a valid method of testing if someone is “too stoned to drive” we have to push back on any attempt to classify marijuana users as ineligible to drive.
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?
Remember when people in this web site would blame the recent increase in accidents on the supposed cognitive decline from COVID and how hooked we are on our phones because of the evil tech companies.
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.
> 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.
>focusing on 246 deceased drivers who were tested for THC following a fatal crash”. That means there could be selection bias at play.
that wording definitely sets off warning alarms for selection bias. but it looks like there were approximately 350 traffic deaths in montgomery county during that period [1]. that probably about lines up with 246 drivers dying during that period, so it seems likely they tested all or almost all deceased drivers.
They failed to present the average _age_ of the drivers as well. Young drivers are more often involved in fatalities than older drivers. This is clear if you look at the NHTSA's FARS database.
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.
Some helpful context: The number of Americans age 12 and older who report using any marijuana product at least once in the past year is around 20% (Source https://apnews.com/article/marijuana-cannabis-alcohol-use-di... ) if I use one of the highest reported use numbers I can find.
Even if you dismiss all of the questions brought up in these comments like the use of mean levels instead of median, not accounting for tolerance of habitual users, or debates about the threshold for impairment, the 40% number in this study is without a doubt far higher than the number of people who have detectable levels of THC in their blood at any given time.
I see a lot of attempts to downplay the result of this study in the comments, but 40% having significant THC in their blood is a stunning statistic no matter how you look at it.
What percentage of people who drive drunk have consumed thc within the time window of blood detection?
Now this is a more reasonable number
I really don't know why this number is significant. Accidents are situational and people who engage in situations where accidents are more frequent likely make other decisions about consumption and lifestyle which involve things like cannabis
Who cares?
You aren't going to elevate the behavior of the population by regulating a plant
The biggest problem with drawing conclusions from the 40% number is that THC use correlates with other well established crash death risks like being a young driver or the use of other impairing substances.
The fact that legalization did not impact the crash rates is also a strong signal that THC itself is not causing the crashes.
The presence of THC in the blood is not a reliable signal for intoxication, so further research is needed to draw any type of conclusion.
Finally, it's also been noted that there are some sample bias concerns because the data comes from fatal crashes where it was determined that a drug test should be administered after the crash.
You can't drive at 12 though surely? And you have to account for the fact that young people are going to be more likely to die in crashes and more likely to use weed.
This kind of test seems silly. It's going to be far too hard to remove the confounding variables. Much easier just to give people different levels of weed and have them do driving tests. Directly measure their driving skill instead of doing it by shitty proxy like this.
> 40% having significant THC in their blood is a stunning statistic no matter how you look at it.
Yes, it is a stunning statistic.
So much so, that in itself it makes it worth questioning the results of this study.
If 40% of fatal crash victims had THC in their bloodstream, and only 20% of the general population did, that would imply a 100% increase in chances of dying in a car crash from having smoked marijuana. That's an absolutely massive risk factor, the kind you would expect to show up very, very clearly in any kind of statistical analysis of car crashes.
But the other thing I've seen a bunch of people cite in this discussion is that there has been no statistically significant increase in fatal crashes following marijuana legalization.
That would imply that either there was no statistically significant increase in drivers high on marijuana since legalization, or there was no statistically significant increase in the likelihood of causing a fatal crash from being high on marijuana.
Based on our knowledge of human nature, the former seems incredibly unlikely (yes, there would surely be some people who would have been smoking pot before who just stopped hiding it as much, but there would also, just as surely, be many people who had been interested in getting high before, but who had been intimidated by its legal status or had no idea how to find a dealer until there were dispensaries opening in every town).
The latter directly contradicts the implication of this study—but this is only one study, and may have methodological issues that we are unaware of.
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[ 2.2 ms ] story [ 79.1 ms ] threadThat 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.
> 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.
Whatever the cause I feel in my gut that if our police did basic standards enforcement people would think twice about lawlessness. I’m in Pennsylvania.
there are days where it happens multiple times during one walk and weeks where it happens at least each day of the week.
i'm actually a car guy but when i drive if i see any pedestrians i always slow down and i take it even easier if i see they have small children or dogs since either can randomly stop or dart away.
1. https://i.redd.it/f898arvdx6je1.jpeg
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.
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...
For drunk drivers it’s rather easy to assess whether someone is impaired. With marijuana it’s not. So until we have a valid method of testing if someone is “too stoned to drive” we have to push back on any attempt to classify marijuana users as ineligible to drive.
50% of the people on this street get stoned before driving to work, every single day
dope isn't even legal here and even if it was DUI is wildly illegal
We can only cure this if we get serious about penalties because we can't undo murder and injuries
How about first time warning, second time weekend in jail, third time week in jail, fourth time month in jail, fifth time year in prison
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.
that wording definitely sets off warning alarms for selection bias. but it looks like there were approximately 350 traffic deaths in montgomery county during that period [1]. that probably about lines up with 246 drivers dying during that period, so it seems likely they tested all or almost all deceased drivers.
[1] https://dam.assets.ohio.gov/image/upload/statepatrol.ohio.go...
Even if you dismiss all of the questions brought up in these comments like the use of mean levels instead of median, not accounting for tolerance of habitual users, or debates about the threshold for impairment, the 40% number in this study is without a doubt far higher than the number of people who have detectable levels of THC in their blood at any given time.
I see a lot of attempts to downplay the result of this study in the comments, but 40% having significant THC in their blood is a stunning statistic no matter how you look at it.
What percentage of people who drive drunk have consumed thc within the time window of blood detection?
Now this is a more reasonable number
I really don't know why this number is significant. Accidents are situational and people who engage in situations where accidents are more frequent likely make other decisions about consumption and lifestyle which involve things like cannabis
Who cares?
You aren't going to elevate the behavior of the population by regulating a plant
The fact that legalization did not impact the crash rates is also a strong signal that THC itself is not causing the crashes.
The presence of THC in the blood is not a reliable signal for intoxication, so further research is needed to draw any type of conclusion.
Finally, it's also been noted that there are some sample bias concerns because the data comes from fatal crashes where it was determined that a drug test should be administered after the crash.
This kind of test seems silly. It's going to be far too hard to remove the confounding variables. Much easier just to give people different levels of weed and have them do driving tests. Directly measure their driving skill instead of doing it by shitty proxy like this.
Surely this has been done?
Yes, it is a stunning statistic.
So much so, that in itself it makes it worth questioning the results of this study.
If 40% of fatal crash victims had THC in their bloodstream, and only 20% of the general population did, that would imply a 100% increase in chances of dying in a car crash from having smoked marijuana. That's an absolutely massive risk factor, the kind you would expect to show up very, very clearly in any kind of statistical analysis of car crashes.
But the other thing I've seen a bunch of people cite in this discussion is that there has been no statistically significant increase in fatal crashes following marijuana legalization.
That would imply that either there was no statistically significant increase in drivers high on marijuana since legalization, or there was no statistically significant increase in the likelihood of causing a fatal crash from being high on marijuana.
Based on our knowledge of human nature, the former seems incredibly unlikely (yes, there would surely be some people who would have been smoking pot before who just stopped hiding it as much, but there would also, just as surely, be many people who had been interested in getting high before, but who had been intimidated by its legal status or had no idea how to find a dealer until there were dispensaries opening in every town).
The latter directly contradicts the implication of this study—but this is only one study, and may have methodological issues that we are unaware of.