Driving while high - Interstate 420, man

June 12, 2005 8:42 AM

If you're driving while high (after smoking marijuana) and a cop pulls you over, is there any test they can perform to tell?

I know it's against the law to drive while under the influence of a drug, but it seems like there's no way they can bust you. The officer might suspect you're acting funny, but a urine test will just show whether you've smoked it in the last few days, right?

Anything else they can do?

Note: I'm not planning to drive while high. Just curious.

posted by anonymous to Law & Government (26 answers total)

There's no roadside test for marijuana use, as far as I know, but if you're swerving or can't walk the line, they could always bust you for reckless driving, at the very least.
posted by Faint of Butt at 8:57 AM on June 12, 2005

I think the urine test they might use tests for the level of THC which stays in your system for ~30 days so not the most accurate in terms of driving while high. This is moreso a test that used for employment & I've never heard of someone getting busted for driving high. However, if you're driving reckless and the cop suspects you are high (most cops can tell very easily), this may constitute as probable cause in their mind to search the car and see if there's some pot to be found.
posted by jmd82 at 9:07 AM on June 12, 2005

The test is simple: if you lunge for their powdered-sugar donut, you're nabbed.
posted by five fresh fish at 9:25 AM on June 12, 2005

I don't think police can force you to take a urine test, for that matter.
posted by Jairus at 9:25 AM on June 12, 2005

The implied consent law (at least in Oregon) covers breathalizer tests specifically. Any other tests they must have probable cause. That said, cops know if you're high, and driving while impaired still is a valid charge (you can also get busted for driving after taking Nyquil/etc - same deal).
posted by devilsbrigade at 9:39 AM on June 12, 2005

Always, always, always go to Erowid for all your drug questions. The site is a wealth of accurate, non-hysterical information about drugs, their effects, their history, their chemical structures, and the laws governing them. The DEA even referred Rolling Stone magazine there for information once because Erowid knows more about drugs than the DEA does. Go check it out! I bet it will answer this question, along with any others you might have.
posted by equipoise at 9:47 AM on June 12, 2005

If you're so high that your driving gets you pulled over, the cop can simply point their flashlight at your face and immediately see how stoned you look. They'll probably be able to smell the weed on you, too.

What I mean to say is, if you're so high that your driving so poorly that you'd get pulled over for it, you're probably so high that it's immediately obvious without any kind of chemical test.
posted by Jon-o at 9:51 AM on June 12, 2005

I am pretty sure the "follow-the-finger-with-your-eye" test is conclusive enough to haul you downtown. When you get to one side or another, if your eyes start wiggling, it indicates motor impairment. I have read (somewhere on the internet, probably, so it must be true) that the finger test is the the only one they actually pay attention to, and that the walking on a line and so forth is just misdirection.
posted by mzurer at 10:10 AM on June 12, 2005

The "follow-the-finger-with-your-eye" test is referred to as the Horizontal Gaze Nystagmus(HGN) test. Just in case you're googling on it. I can't really say whether it's used for all drug impairments, but it's used by the police when alcohol consumption is suspected.
posted by zpousman at 11:10 AM on June 12, 2005

What I mean to say is, if you're so high that your driving so poorly that you'd get pulled over for it, you're probably so high that it's immediately obvious without any kind of chemical test.

I don't think this is the case. And I don't think being pulled over necessarily implies that one was driving very poorly. I've never gotten pulled over, personally, but it's not like they need very much of a reason.
posted by ludwig_van at 11:35 AM on June 12, 2005

As part of marijuana decriminalization legislation being proposed in Canada, the bill provides for specific and strict(er) criminal penalties for driving while stoned. What specific means they have to be able to do this (a la breathalyzer) is not known to me.

I can say that the numerous posters who insist that cops will "just know" you're stoned are spouting total nonsense. I have witnessed many a very stoned stoner being pulled over (broken tail light, routine check, speeding, etc.) and never once has the police officer made any indication that they knew, or suspected. This over a period of fifteen years, sample size: n > 15. (Just the crowd I was hanging with in high school)

Even slight tipsiness is far more easy to detect than marijuana use, in my opinion.
posted by bumpkin at 12:07 PM on June 12, 2005

There are police officer who are trained to do a variety of specific tests that are presumptive (not conclusive) for people who are high. These officers are known as Drug Recognition Experts, and they can often tell after their tests that you are indeed high.

Canada expects to have quite a few more of these officers if the decriminalization of marijuana goes through. There are some out there anyway.
posted by birdsquared at 12:31 PM on June 12, 2005

A friend of mine here in Oregon was pulled over and while she had smoked pot 12 or so hours earlier in the day, she was no longer high. In any event, after finding a pipe in the glove box (...she didn't know her rights...) he "determined" she was indeed high at the time she was driving and she got busted. The only "proof" she was high, was his determination based upon some sort of training that (some...) cops here in Oregon get. Complete BS I say, but regardless she got busted.

Smoking dope twelve hours ago does not make you high; obviously this guy's training was worthless if he thought she was any higher than the average person who is tired or nervous.
posted by pwb503 at 1:29 PM on June 12, 2005

The answer: No. And this is one of the barriers to legal pot in the US. Without a roadside test, and since pot can and does impair reaction time, it's yet another argument held out by those who are against the legalization of pot.
posted by klangklangston at 1:29 PM on June 12, 2005

Do you have to preform these tests? In illinois we were always told that if the officer asked you to perform a field sobriety test it means they are looking for probable cause (meaning they have shit). The correct response to his request is "no, if you need to arrest me, please do so now."
posted by jmgorman at 1:29 PM on June 12, 2005

Personally, I feel that all DUI charges should be based solely on reaction time and judgment tests, rather than the quantity of any substance in one's blood.

I would never drive if there's even a *chance* of me being over the legal limit. However, even after a few beers my RT is better than that of an average septuagenarian.
posted by Eamon at 3:45 PM on June 12, 2005

Do you have to preform these tests?

In Oregon, there's implied consent, which means that if you drive, you consent to a breathalizer test any time a police officer wants to. If you refuse, you get arrested. I don't know what its like for other states though..
posted by devilsbrigade at 4:02 PM on June 12, 2005

In Arizona, you're considered under the influence of a drug if it can be found with a blood test (which is routine in case of an accident with a death or major injury). At least, that's what they tell you in traffic school. I don't know if that would hold up in court, though, or when the police are authorized to do a blood test.
posted by gokart4xmas at 4:34 PM on June 12, 2005

Arizona also has implied consent. If you dont give up a blood and/or urine sample, you lose your license for a year. Above that, the officer can/WILL get a warrant for the blood/urine sample anyway. Sooo... you're rarely ever better off to refuse.

Technical note too: all that has to be proven in court on DUI cases is impairment - even below the legal limit. If your BAC is above the legal limit, impairment is assumed.
posted by whatisish at 4:38 PM on June 12, 2005

Colorado has implied consent as well. Blow or go to jail.

1. Breath can be an indicator- directly after smoking, you will have mj-breath for 15 minutes or so.
2. Tongue. After smoking, a greenish cast is laid on your tongue. Scraping will remove it.
3. Motor skills. Most cops will run you through their standard DUI checks. This will catch the highest of people.

To sum it up- there aren't conclusive tests. At all. The effects of MJ are too varied on too many people for there to be a confirmative test, unlike alcohol.

As an aside, it's intelligent to know your limits. Some can smoke and drive. I know many others who cannot. Drugs have different effects for different people, and you need to know what your own effects are- this is how you protect yourself if you decide to mingle with the public-at-large after treating yourself to goodies.

I've personally been pulled over while in that state (license plates, not driving!), and nothing came of it- I didn't draw attention to anything that would tip it off.
posted by id at 5:50 PM on June 12, 2005

They don't have to know what you've been smoking, but there are field tests that can indicate that a person is Driving While Intoxicated. Last week I sat on a jury panel for a DWI case in Texas, and they said DWI consists of one of three conditions being met:

1. Blood alchohol of 0.08 or greater;

2. An imparement of physical ability due to a foreign substance; or

3. An imparement of mental ability due to a foreign substance.

If a cop does a field sobriety test and a person fails either 2 or 3, it doesn't matter what substance intoxicated the person; he is DWI.
posted by Doohickie at 6:22 PM on June 12, 2005

In GA, you can refuse to have a road-side sobriety test and demand you be taken to any hospital or place that tests for sobriety within 60 miles. However, if you demand as such, the officer can decline to take you but that also causes you to loose your license for 6 months. Basically, it's a way to prevent a DUI by loosing your license for 6 months if you know your SOL.
posted by jmd82 at 6:46 PM on June 12, 2005

In California, they actually have the right to draw blood, even at the side of the road. Of course, you can refuse, but they will take away your license for some period of time. I've never actually heard of this being done, except if you are in an accident and taken to the hospital, in which case they will ask a nurse to draw the blood...
posted by darkness at 7:24 PM on June 12, 2005

in which case they will ask a nurse to draw the blood...
I thought in this case, unless that of death, that the police couldn't use information garnered by the hospital without your consent because of patient confidentiality.
posted by jmd82 at 8:01 PM on June 12, 2005

In the state of Victoria here in Australia, police have the power to conduct random roadside saliva testing to detect drivers travelling under the influence of illicit drugs.

However, the system is facing some controversy for returning inaccurate results.
posted by elphTeq at 8:03 PM on June 12, 2005

Some advice if you get pulled over and asked to perform a field sobriety test (and know you have NOT been drinkinkg): Do not take the field sobriety test. Ask for a breathalyzer instead.

Whether you pass or fail the field sobriety test is completely subjective and if a cop wants you to fail, you will fail. Don't give them an excuse to bust you.
posted by Justinian at 10:27 PM on June 12, 2005