THE FIVE-NANOGRAM RULE
Of course, all of this hinges on having a legal standard to measure against. Some states in the U.S. where medicinal marijuana is legal have already established zero-tolerance policies for driving under the influence of cannabis; get caught with THC in your bloodstream while driving and it's an immediate conviction regardless of how much THC that is (or whether it is the cause of your impairment). But with Washington state and Colorado opening the door to legal, recreational use of cannabis their legislatures are choosing -- like several other medicinal marijuana states -- to treat cannabis more like alcohol. That is, you can toke a responsible amount and still get behind the wheel, but should you cross a certain threshold you are in serious legal trouble.
So where does the five-nanogram-per-milliliter rule established by both Washington and Colorado come from? Not from Washington or Colorado. It's an administrative decision that might seem somewhat arbitrary, though it's no more arbitrary than decreeing that somewhere between .07 BAC and .08 BAC a person transforms from capable to dangerously drunk. The five-nanogram rule is rooted in several studies and for several scientific reasons, the first of which actually sides with the regular marijuana user. In the first studies that emerged showing that blood tests could detect residual THC in the bodies of chronic cannabis users even days after they last dosed, none of those chronic users registered higher than five nanograms per milliliter at 24 hours after their last dose, Huestis says. So the rule is in part designed to reduce the likelihood that chronic users will get slapped with D.U.I.D. convictions when in fact they haven't consumed cannabis in more than a day.
The other reason states tend to gravitate toward the five-nanogram rule is far more nebulous, but there's some scientific evidence, borne out by data, that when THC counts in the bloodstream of a driver are at five nanograms per milliliter or higher, that driver's chance of being involved in a fatal accident begin to climb steeply. One Australian study found that with any measurable THC in the bloodstream a driver is twice as likely to be involved in a fatal accident, but at five nanograms per millimeter of THC that number jumps to 6.6. times more likely, Huestis says. Five nanograms is the point where the chances of something bad happening seem to start climbing steeply.
But that's not really so clear. Some German studies have shown significant impairment in subjects testing in the area between two and five nanograms per milliliter (Germany is considering adopting the five-nanogram standard as well) and in Sweden, where standards for impaired driving are among the most rigorous and enforced by stringent legal penalties (the legal BAC limit is 0.02, or a quarter that of the U.S.), one laboratory found that 90 percent of that country's cannabis impairment cases had a level of one nanogram of THC per milliliter. So where impairment is concerned there's a lot of gray area -- and a lot of scientific debate -- between zero nanograms and five nanograms per milliliter, not to mention a lot of varying opinion on what constitutes "impaired."
But ultimately the long-sought portable roadside THC test for law enforcement may be less important than many have made it out to be. After all, in the eyes of the law no one really cares how impaired you are, only that you are impaired. That's the way it works for alcohol impairment, and the way it has worked for years. Though easier to measure and evaluate at the roadside, blood alcohol concentration really has no quantifiable correlation to how impaired a person is. Alcohol affects different people in different ways, but regardless you still go to jail for driving in the U.S. with a blood alcohol concentration that tops 0.08 (celebrities and the politically well-connected notwithstanding). How capable you really are of driving is beside the point.
Like the five-nanogram standard, the 0.08 blood alcohol concentration limit was an administrative decision. And as with the 0.08 rule, governments will likely simply set THC standards wherever the existing body of science makes them feel comfortable. Creating such a threshold not only establishes a firm legal standard that can hold up in court, but it somewhat obviates the need for precision roadside testing -- a simple field sobriety test for THC impairment testing for time and depth perception, coordination, and other psychomotor abilities tied to cannabis impairment will do, and officers already have those kinds of tests in their collective toolbox.
Of course, a reliable 'breathalyzer' for marijuana -- something easily administered at the roadside that's capable of returning a number that, like blood alcohol concentration, correlates roughly to a degree of impairment -- isn't completely out of reach. If the new recreational marijuana laws in Colorado and Washington state have created something of a regulatory headache, it's a headache that recreational pot laws might also be able to cure. If necessity is the mother of invention, these new laws have certainly created a need among the legal community that is helping to focus the science and technology community on potential solutions.
"This is a hot area right now, and there really is a lot of attention being paid in my field to oral fluid testing for drugs of abuse in general," Kahn says of the potential for a portable THC testing device. "The kinds of issues we're talking about are exactly why. This is where it's headed. It may not happen in exactly the way that we think, but in one way or another I think it will happen sooner or later."
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)