When Colorado and Washington state each passed ballot measures legalizing marijuana for recreational use late last year, one legal challenge was resolved, but another was just beginning Before, marijuana was simply prohibited. Now it has to be regulated. With their new legal standards for possession and use, Colorado and Washington now have to draw hard lines on a rather hazy landscape, creating legal standards not just for for taxation and licensing, but also some far more nebulous questions, like how much marijuana is reasonable for a single person to possess, and even what constitutes legal intoxication. Meanwhile, forty-eight other states are watching closely to see exactly how they do it.
For Colorado, regulation of marijuana under the new state standards (which, by the way, could still be challenged by the federal government) came to a head last month at the state house as legislators hashed out just exactly how local and state authorities will handle these questions. They also tackled the thorniest issue of all, one that has been a sticking point for previous legalization efforts and one that is eventually bound to go 'round and 'round in courtrooms: what scientifically constitutes "under the influence" of marijuana, and how can clinicians and law enforcement determine if someone -- most importantly, a driver -- is too high for the public good?
Now the state of Colorado has offered up its answer. Under House Bill 1114, the answer is five nanograms. If a blood screen detects five or more nanograms of THC (that's delta-9-tetrahydrocannabinol, the psychoactive ingredient in cannabis) per milliliter of blood in a person's bloodstream, that individual is considered legally under the influence of drugs. Washington has also set its intoxication limit at five nanograms per milliliter.
But the question is not that simple. What is marijuana impairment -- what constitutes being "too high" to drive -- and how can we scientifically evaluate it, particularly in a law enforcement context? Moreover, how can police officers test for it conclusively at the roadside, where blood tests aren't available? How lawmakers define and answer these questions will have a lot to do with marijuana policy in the U.S. going forward, and unfortunately the body of science describing marijuana's effects on the brain and body -- though vast -- isn't exactly bound by broad consensus. Five nanograms per milliliter is a place for policy to start, but it's by no means the last word determining how high is too high.
TAKING THE HIGH ROAD
"Smoking is a very efficient way to deliver drugs to the brain," says Dr. Marilyn Huestis, a senior investigator at the National Institute on Drug Abuse's Intramural Research Program, part of the National Institutes of Health. "It goes into the lungs, into the heart, and gets pumped directly to the brain."
Huestis has spent a career studying the effects of marijuana on the brain and the psychomotor capabilities of individuals, both among acute users (those that use marijuana occasionally) and chronic users who partake of marijuana daily. Unlike alcohol, which requires at least a little bit of time to work its way into the bloodstream, marijuana has shown in Huestis's own studies to manifest itself within the first minute after use. From there, one's ability to responsibly operate heavy machinery begins to come into question.
Cannabinoid receptors (known as CB1 receptors) in the brain are found in many key regions, including the amygdala (responsible for processing memory and emotional reactions) as well as the basal ganglia and cerebellum (responsible for motor control, among other things). "We know that when people smoke marijuana the lose some of their peripheral vision," Huestis says. "We know it affects the passage of time, or the idea of how rapidly time is passing. It affects balance. And one of the most interesting areas it affects is the prefrontal cortex."
The prefrontal cortex is what separates us from other animals, Huestis says. It's home to our executive function, the place where we take in and process information and use it to make choices about various courses of action. Cannabis impacts our executive function, which can slow or alter decision-making abilities. Moreover, it makes our brains work harder, Huestis says, and not necessarily in a good way. In tests, an individual dosed with cannabis can often perform a task just as well as he or she would if sober. But brain imaging of dosed individuals shows that it requires much more brainpower to complete that task. That means that under the influence of cannabis the ability to handle multiple tasks simultaneously, or to divide attention effectively, dwindles significantly. Even more specific to driving, marijuana has been shown in various studies to affect what's known as "standard deviation of lateral pursuit," or that natural, somewhat innate ability to hold an automobile more or less right in the middle of a traffic lane.
None of this -- reduced peripheral vision, slowed decision making, inability to multitask -- enhances one's ability to drive. Humans are more prone to distraction when dosed with cannabis, and in the context of a moving vehicle a misperception of the passage of time translates to a misperception of distance as well, at least in the sense of how quickly a car traveling at a given speed will reach some distant object.
That being said, Huestis notes, individuals under the influence of cannabis -- unlike those under the influence of alcohol -- tend to be aware of their impairment. Some studies have shown that stoned drivers are more cautious behind the wheel and tend to drive more slowly. But that's not really any kind of compensation. Driving is an exercise in timing, multitasking, and situational awareness -- and not one well suited for the cannabinoid-impaired.
THE ELUSIVE MARIJUANA 'BREATHALYZER'
"The properties of marijuana are not going to liken themselves very much to a 'breathalyzer' type test," says Dr. Christina Hantsch, a toxicologist working within the Loyola University Health System. "I think it's going to have to be a different bodily fluid if you're looking for more immediate testing."
Why? For one, THC is fat-soluble, which means it can be absorbed by the body's fat cells and remain within the metabolism for extended periods of time. For heavy users, THC can remain within the body for days, making it difficult to connect the presence of THC in a person's bloodstream with that person't current state of impairment. For chronic users the picture is even murkier. Regular marijuana users who stop using cannabis can still have detectable amounts of THC in the bloodstream even 30 days after they cease using. There are even documented cases of former chronic users that haven't had a dose of cannabis in years testing positive for THC while undergoing rapid weight loss, Hantsch says. THC is really good at tucking itself away in the body's fat cells, and it can remain there for a really long time.
Complicating things further still: an emerging body of scientific evidence suggests that this residual THC in the bloodstream of chronic users might still cause impairment. Though the effects of these trace amounts of THC in the bloodstream don't manifest themselves with nearly the intensity that a fresh blast of THC to the CB1 receptors does, both Huestis and Hantsch note that there is research out there suggesting that just because these levels of THC are relatively low doesn't mean they aren't having some impairing effects on the psychomotor skills of both acute and chronic users for the duration that THC remains in the bloodstream.
All that is to say that detecting the presence of THC in the bloodstream doesn't necessarily correlate to impairment, and there's certainly no overwhelming body of hard science that can draw connections between a specific amount of THC in the blood (like, say, five nanograms per milliliter) and a specific degree of impairment. Things grow more dubious still at the place where government really needs certainty the most: at the roadside.
The most promising solution for the problem of roadside THC testing in recent years has been oral specimen testing (read: saliva sampling). Several academic and government labs as well as commercial companies have developed various tests claiming they can detect THC in the bloodstream via handheld devices that analyze a swab taken from inside a subject's mouth. But the results have been mixed -- mostly mixed degrees of disappointment.
"Oral fluid testing actually went into effect in Australia in 2004," Huestis says. "The reason it didn't get going in Europe or the U.S. is because the roadside devices were, frankly, terrible."
You can get really good results from THC testing via oral sample in the lab, Huestis says, but the problems with collecting and analyzing samples at the roadside became immediately apparent to early adopters of the portable oral specimen technology. First, THC is so lipophilic that it had a tendency to stick to the collection devices themselves, which dulled the sensitivity of the analysis from the point of that samples were collected. Saliva is also loaded with enzymes that break molecules down, so in the period between collecting the oral sample and getting it to a lab for analysis the samples would continue to degrade themselves, further skewing the results.
But assuming there was an oral specimen test that was effective for accurately measuring THC in the bloodstream at the roadside, there's still the problem of correlating it to impairment, which is ultimately what law enforcement officers are concerned with, especially in a context where possession and use are no longer strictly prohibited.
"There's still a lot of work to be done to really tie in all those connections, to say that if you do pick up this level of a marijuana metabolite in a oral fluid specimen there is some solid scientific evidence that also indicates some degree of impairment or effects on the behavior of the individual," says Dr. Stephen Kahn, a professor of pathology and toxicologist at Loyola University's Stritch School of Medicine. "And that's harder to do than with blood ethanol."
Nonetheless, the state of both the science and the technology is improving. The tools for oral specimen detection and analysis improve each and every year, Huestis says, and her own lab recently folded trials of a new portable oral specimen diagnostic into experiments there. Under controlled conditions in which the THC levels of dosed subjects were being tested independently in the lab this new portable device showed impressive efficacy, Huestis says, with very low incidence of false negatives or false positives.
Huestis thinks we'll see these kinds of tests used by law enforcement in the U.S. within 3-5 years. Kahn is less willing to put a firm projection on the adoption of such technologies, but he does believe that the science will eventually become good enough to gain the confidence of the courts and law enforcement.
"I think it's absolutely going to happen," Kahn says. "But I'm just not sure how long it will take."
Shouldn't be that tough. Base it on how long it takes to answer simple questions. IF it takes more than 10 seconds to answer "What's your name?" that person is soooo wasted.
or you could count the Doritos bags.
It's even easier than that. People have been driving stoned for generations. And police have been evaluating a person's intoxication level, whether by alcohol or any other drug, for just as long. What's the difference now that pot is legal? Nothing. The law still says you can't drive while under the influence. So the same criteria they used to determine 'under the influence' before it's legality can still be used now. The only difference is punishment. This is just another nonsensical poopsci article. I know one thing; You can always tell if a poopsci writer is stoned by the length of his article.
oh wow man, I can write forever!
Today's magic is tomorrow's technology.
Or just toss them a rubber ball from 10 feet away, underhand. If they can catch it, they can react to the road. And to be sure the toss was not unreasonably fast, they can do it in front of the dash cam.
Is this a trick question? There is no such thing as a cannabis-impaired driver.
HAHAHA-" Driving is an exercise in timing, multitasking, and situational awareness" all skills that 99% of the drivers in my area, wash dc dont possess. Looks like the stoners aren't at much of a disadvantage after all.
why not treat it like we treat drinking and driving?? Place the same restrictions. Its not going to stop some people from driving impaired (some people drink and drive despite the law) but getting caught lands you in jail and fines and all that stuff...
Weed is no different. Just treat it like alcohol..
Since drivers 'impaired' by marijuana have been on the road as long as there's been roads, I don't see the relevance of the question posed by the article.
Irresponsible people will continue being irresponsible, and the responsible will continue being responsible, hopefully.
It maybe a legal drug, but it is still a drug. If you decide to over do on cough medicine or anything else and it effects you actions while driving in a negative way, YOU are LIBABLE!
lol at everyone thinking this is silly because weed makes you super human. If you can't stop giggling at a wall for 10 minutes straight... maybe you shouldn't drive.
Nobody should drive while impaired. However, for a regular (daily) pot smoker, of which there are tens of millions in this country, pot does not cause impairment.
If we're going to judge whether or not other people should be allowed to drive based on our own experiences with various substances, then I would suggest we ban driving under the influence of nicotine, as the last time I tried nicotine, it nearly made me pass out.
Sad that Americans have been so propagandized they no longer know which way is which. FIRST the police in any arrest are supposed to have or be able to gather proof. This is done by a sobriety test a PHYSICAL test. What the politicians want is just to punish not for any wrong doing but for the money.
Also keep in mind just because pot is now "legal" DOES NOT MEAN that all of sudden there are more pot drivers. There have ALWAYS been pot drivers and it hasn't EVER BEEN A PROBLEM. Never not once. This does NOT mean that it's always okay to drive under the influence of pot but should force law enforcement for once to do their jobs in a legal fashion and actually have proof. After all in our aging population with all the horrible senior drivers who we all know drive like they are drunk NEVER get arrested or even a ticket yet they create accidents wherever they go.
So let's keep this in perspective: the voters want it legal yet the governor refuses to do his job. Instead we have to hear him whine and bitch and try everything he can to usurp the law and the desire of the citizens. It seems to me that this ought to be a serious crime instead it's just biz as usual.
It's sad how media driven the comments on a supposedly science based website are. Anybody saying that weed is just like alcohol and should be punished the same as far as driving goes is insane and basing completely on their reefer madness irrational. Same goes for the people saying things like “if they take more than 10 seconds to answer a question,” or if they are “sitting there giggling at a wall”… Seriously, this isn't salvia or some hallucinogenic, let’s be realistic. I’d never say I was too impaired to drive from weed, nor have I ever sat their giggling at a wall uncontrollably because I was too “high”. Can we set our irrational biases aside please? As if you have the moral high ground and it’s easy to identify marijuana smokers… News flash, they are all around you.
@ Littlebigman: I'm glad both of our comments start with "It's sad," because i was disgusted how ignorant some people are on the subject.
I just think it's funny how many pot fan boys (and girls) there are. I used to smoke, in highschool and early college. I was around it a lot, had friends that were dealers, growers, etc. I'll agree it is different, but it is impairment. As opposed to alcohol, I usually was less aware of how impaired I was. So we all aren't brain washed by Fox News and the government. Some of us just grew out of sneaking around smoking in the shadows because, honestly, it wasn't worth it. It is way too much trouble considering the legal aspect and occupational drug testing (unless you live in those two states). Sorry I don't feel like being a weed freedom fighter.
@Johnt007871: I didn't say you had to be a pot fan boy. I'm just saying be realistic to the effect it has on people and the level of "impairment" it causes. I agree, people feel in control when driving under the influence of alcohol even when they are not; Marijuana is another story, you're no less in control than driving sober. I don't live in one of those states, and it is a hassle, but millions of people are going through the hassle, millions of people are driving on it (let's say thousands to be fair, i don't really know that it's millions), and the people who have no idea what the real effects of it are also have no idea the drive on the roads with people who recently smoked every single day.
You know, if those lazy cars would just drive themselves we wouldn't have these sorts of problems.
Being sleeps deprive, leaves an excess of toxic chemicals in our body and causes poor mental processing and reflexes. If we are sleep deprived, taking some home medicine, smoking pot or drinking alcohol or well just anything, we are all still obligated by law to be coherent sober responsible drivers.
@ Adaptation: Tell google to hurry it up already then.
@Wonder/robot/12/...: I don't think anybody is stating we aren't obligated by law to be coherent responsible drivers. But your comment is, without directly saying, equating driving while sleep deprived with driving under the influence of alcohol or weed. That's the point here, people will blindly consider these things equal risks and that just isn't the case.
I'd rather have a stoner driver next to me in traffic than a drunk driver swerving everywhere.
This is absolutely stupid. People who are too stoned to drive don't tend to drive. People who are too drunk to drive- drive all the time. The two are not comparable at all. Additionally, at least in someone whom I know very well (!), MJ does not impair coordination at all. Not one detectable bit. Yet another waste of taxpayer money.
Agree with many others that this is a ridiculous concept. I've never know a pot smoker to get in or cause an accident from being stoned. Ever. It doesn't happen. It's not like drunk drivers.
Also agree that it's not like this is a new thing. Pot smokers have been around driving for as long as we've had cars. No one ever really noticed 'impairment' before...
The ignorance in this comment thread is surprising...especially coming from smokers...
I have several friends who have gotten in car accidents when they were stoned (2 of them because they were stoned, and not paying attention). Is this a good sample size to reflect the rest of the nation, let alone two states who legalized marijuana? No. Is the fact that people have been smoking weed and driving for a long time any justification for being allowed to drive under the influence? No. People have been drinking and driving since cars were invented too. Just because it something that people choose to do and will always continue to do doesn't mean it is legally acceptable.
Drunk drivers don't think they are impaired when indeed they are, and wind up hopping in cars. Like it or not weed is similar in this regard. Anyone who thinks they aren't impaired when they smoke is simply a victim of the wonderful effect weed has on our limbic system. Like it or not, if you smoke, especially often, you are most DEFINITELY impaired. You just don't realize it...(especially if you are a daily or high frequency smoker).
Now I'm not trying to elude the fact that alcohol is by far worse when it comes to impairing your ability to drive. I think is a pointless argument...but it is important people realize that they are indeed impaired when they smoke, and if they find themselves in cars after smoking OFTEN, then it might be time to consider that you have a problem...
A long, long time ago I tried the weed in college. I was a laughing mess when I left the house to go home. Lived out in the country just outside of town. In town everything seemed fine I could tell I was buzzing but was able to easily follow all traffic laws.(except impaired driving) However when I got out of town and had to drive 55mph well that was a bit different. I got up to speed but felt wildly out of control I assumed I was speeding so I slowed down till I felt like I had control of the car...looked down at the speedometer to see if I was at 55 or 60. Nope I was driving 30mph. 30mph! I laughed thought to myself this is waaay to slow I'll get pulled over for sure 30 in a 55 whats this kids deal. So I started back up to 55/60 mph. Again I felt out of control! I slow and look down to see what speed I was at. Somewhere close to 30mph again! And that's just how I had to drive home. Lucky for me the drive was brief I got home without incident but I'd have to say without a doubt I was impaired.
To the fools such as pete444 that want to argue the differences in alcohol and marijuana impairment, well, talk here is cheap.
The families of those killed and injured in Philadelphia last week when an admitted marijuana user operating an excavator caused a masonry wall to fall onto an adjacent thrift store.
Go tell them.
Some tell us that it is impossible to overdose on marijuana as it is on alcohol. Who the hell cares if they kill themselves if they are killing those around them?
@kevin56: An "admitted marijauna user"... really? Care to provide some links to this story? Was this person high at the time? Why was it the marijuana that caused the accident? Maybe they were just a bad at their job. Obviously we could go back and forth with that argument, but any daily smoker knows they are not impaired when they smoke. You can give my as much anecdotal evidence as you want, and i'll fire back with mine. But whether or not you want to believe it, it's true.
I will admit, that if i got behind the wheel of a car the first few times i smoked, i probably wouldn't be a good driver. I'd have been too distracted from the new experience. But anybody who has smoked more than a handful of times can easily hide it because they are not a sloppy mess like you seem to believe.
People aren't "killing those around him" because of marijuana. Go back into your bubble, let the rest of society evolve.
What is the legal limit then... I say if you can create music like Jimmy Hendrix, The Beatles, The Doors, John Lennon, Led Zep, Red Hot Chili Peppers, and all the greats then you have reached that limit. But hey look at the bright side, your music will live for ever.....
Wellllll... i mean, i doubt most of those bands music was heavily influenced by marijuana... I mean Anthony Keidis was a heroin junky primarily (loved scar tissue, the book that is). And was Jim Morrison ever NOT on acid? So, to the point of your comment, if you claim you can make music like those greats (and very glad you included RHCP in that list) the cop may be more concerned about real drugs than your marijuana "impairment" lol.
"any daily smoker knows they are not impaired when they smoke"
Just because a daily smoker has a higher tolerance and is used to the effects of marijuana doesn't mean he/she is not impaired. If you are high, you are impaired. You can try and argue this all you want, but whether you are an experienced smoker or a novice, you will (on average) still have impaired cognitive functioning, motor control, and memory...
@TheKID11: Ok, care to post a link to the study you read about this? orrrr are you just pulling it out of your @ss? Try to stay away from the Nixon era studies in which they suffocated monkeys to prove it kills brain cells if you don't mind.
No, I didn't pull this out of my @ass. I study the endocannabinoid system for a living, and am glad you are interested enough in looking over some articles.
I'll link you a few for now, which you should have free access too, but I will not link too many because it would be far too much effort to spend time looking up and linking all of the articles that illustrate the effects of THC on cognitive functions, attention tasks, memory, learning, etc.
Here are a few article titles and authors. I won't post links because Popsci has issues with this sometimes in the comment threads, but feel free to look them up. As I indicated though, these hardly reflect the large quantity of research articles on the subject, so feel free to investigate for yourself.
Cannabis effects on driving skills; 2013 (Hartman RL, Huestis MA)
Dose-related modulation of event-related potentials to novel and target stimuli by intravenous Δ⁹-THC in humans;2012 (D'Souza DC et al)
Neurophysiological functioning of occasional and heavy cannabis users during THC intoxication;2012 (Theunissen EL et al). You will like this one because it illustrates physiological tolerance in heavy users, but still shows general impairments.
Effects of Chronic, Heavy Cannabis Use on Executive Functions; 2011 (Rebecca D. Crean et al).
Cellular and intracellular mechanisms involved in the cognitive impairment of cannabinoids (Puighermanal et al)