Driving under the influence... of marijuana

My SO brought this question up last night when we were driving. How can cops tell if someone is driving stoned? Do people honestly get arrested for that, or do the cops go for something more provable and likely to get jail time, like possession? How can a cop determine you’re stoned? It’s not like they have a breathalyser for pot.

I don’t smoke pot anymore, but my recollection of the effects of the drug makes it seem like it’d be hard to spot a stoned driver. It’s not like they’d be swerving all over the road. Plus, if a cop pulled you over for a broken taillight or something and you were high, how would they know? I know people who don’t smoke but have that slow, stoner tone of voice. Or people with naturally squinty eyes.

A guess, as someone who is not a cop or lawyer, but does have a DUI. :mad:

They look for general signs of intoxication: slurred speech, red eyes, incoherence, lousy driving etc. That gives them probable cause to assume that you are under the influence of something, and thus get a blood test done.

It’s true that the cop doesn’t actually know what your speech patterns would be normally; or you could have hay fever and hence bloodshot eyes. It just gives them a valid reason to order a test.

This could be a stoner myth (like “Are you a cop, you have to tell me if you are”) but I had always heard there’s no chemical test to show if you are high or not. There are tests that can show if you’ve ingested pot but they don’t show if you are currently high.

They usually just shine a light into your eyes or check your pockets for visine. It just gives them an excuse to search your car.

Yeah, I was thinking about that, because doesn’t the THC build up in your blood stream, thus enabling potential employers to see that you have smoked pot in the last month? Unlike alcohol, which, I believe, is out of your system in less than a day.

I have a VERY hard time beleiveing that possesion of Vising is probably cause to search your car, and if red eyes count, alot of people would have problems during allergy season.

THC doesn’t build up in your blood, it builds up in your fat (it’s fat soluble). But yeah, that’s why it can be detected for about a month (plus or a minus two weeks or so depending on how much you used) after the last time you used it.

I was told in a class about selling alcohol and tobacco that in Louisiana at least – and probably most states, I’d think – that it doesn’t matter if you are drunk, high, or on just about anything else. If you are stoned and it’s affected your driving to the point they pull you over, you’re in trouble. The point is that you shouldn’t be driving if you’ve got anything, legal or otherwise, in your system, that messes with your driving.

Your state/country/planet may vary, of course.

In my experience, people don’t often get arrested for DWI/DUI for driving under the influence of marijuana. I won’t say it’s never happened, but I’ve never seen it happen. 99 times out of 100, probably more, it’s alcohol. I coincidentally did have one just yesteday that was not alcohol related, but that’s rare, and it didn’t involve pot. The main danger with pot (legally speaking) is that your clothes, your fingers, and your vehicle are going to reek of it and give the officer probable cause to search it and bust you for possession.

I’ve actually wondered this question myself. Because there is no on the spot way to tell if one is high, and plenty of reasons for them to seem “stoned”, I’d assume possession of marijuana or paraphernalia while driving would not lead to a DUI.
Most police officers in my experience, are only moderately concerned with individuals smoking marijuana, and often just confiscate and do not even cite or ticket.
One of my buddy’s (He’s good for his word) got pulled over smoking a pipe, and the officer said because the pipe was still warm, he could get DUI. But this maybe cops trying to fool stoner. I once had an officer say he knew I was smoking because of “green slime” on the back of my tounge that he noticed while I was talking.

But if a cop pulls you over while your high, for a moving violation, DUI maybe possible, and if he thinks your high a ticket of some sort is most likely inevitable (unless he’s “down”). Try these lines…
I haven’t been sleeping much.
I’ve been sleeping too much.
I just woke up.
I was yawning.
I just had a sneezing fit/feel like I’m going to sneeze.
I have allergies.
I was swimming earlier, chlorine bothers my eyes.
And remember, your the only one that can let them search your car. Even if they claim they have likely cause, let them know you contest it.

Some information here.

Development of such a bad-dream-like thing has been attempted.

Note the date of the article: 19 Nov 2002. Field tests apparently were not without problems, or we’d be seeing these everywhere by now.

If Delta-9 THC is detected in a blood sample it indicates that the individual is currently under the influence. It cannot be detected in a urine test so it is harder for the state to obtain a conviction. Urine tests will only detect the presence of THC not the Delta-9 element so it only indicates that at some point in the thirty days prior to the test the person ingested pot. However, many areas have officers designated as DRE’s (Drug Recognition Experts) (they are not really experts at anything, but the title impresses jurors) if you select a urine test the “DRE” will produce a long “cut and paste” report explaining how they observed “objective symptoms of intoxication” which is usually enough for most jurors. The will usually state that the person had slurred speech, rapid heart rate, white coating on the tongue, smelled a strong oder of marijuana, that the person displayed lack of coordination and an unsteady gait. All this plus a positive urine test will often result in a conviction. None of these plus a positive blood test indicating high levels of Delta-9 will also often result in a conviction.

Little known fact, many DUI’s are the result of legally prescribed drugs even over the counter Nyquil can result in a DUI conviction. (in California)

ETA: Here is a good link.

Old Joke… Road side “pot test”… Cop pulls you over, walks up to car… You roll down window… Cop asks you"Woah! Duuuude! Would you like some nachos?"

Here in Canada, a police officer can ask you to surrender your driving priveleges for 24 hours if they feel you are impaired. By “Impaired” they mean any condition which would prevent you from driving with undue care and attention. These conditions can include but are not limited to "Tiredness/exhaustion/illness/stress/emotional instability/distraction(s)/or lack of required prosthetics (eyeglasses), lack of driving skill for road and weather conditions, and others, on the officer’s discretion.

NOTE: these “conditions” to not include intoxication from alchohol or drugs.

I don’t have a particular “cite” for the above, it comes from having had a gf who’s dad was a cop yrs ago.

And now I will close with a joke… A Hippy is driving across the Golden Gate Bridge, after smoking a doob. It getting him a lot higher than he expected… The sun glinting off the waters are beautiful and sing to him of the perfection of beingness. The music on the radio has depth and meaning he has never seen before. Just then, he notices a cop car following him. He slows down, and drives extremely carefully, as the effects of the dope grow even stronger.

As he leaves the bridge, the Lights come on, blue and red. He pulls over, and sees the cop in his rear view mirror leap from the cruiser, and stomp up, face red with anger.

He rolls down his wiondow, and before he says anything, the cop screams “DO YOU KNOW HOW FAST YOU WERE GOING!!!” The hippy realises he has no idea, and guesses “Uhhhh, 50 mph?”

The cop goes white with rage, and yells “YOU… WERE…GOING…6 miles an hour!”


as a nonpot head I can tell you without a doubt there is a very solid chemical test for pot, its called your nose. potheads and drunks seem to forget that they stink alot. it would be easy as hell to notice the smell and then work from there.

There’s a good reason for that - besides the medicinal content, Nyquil has a fairly high amount of alcohol in it.

But there are other things that smell like marijuanna. There are things that smell similar (pine needles, rosemary, skunks) and there are things which even ardent potheads can’t tell apart from marijuana (moxa, and of course mugwort). There are also smells which are stereotypically (and even typically) used by marijuana smokers, and so non-users often confuse those smells with marijuana, but they don’t unnecessarily indicate the presence or recent use of marijuana (patchouli, nag champa, sage).

Your nose is telling you that you smell the aftereffects of some burning plant matter, but it’s not a “test”. It’s more of a hunch and a logical leap of faith.

If your smoking in an enclosed area (like your car with the windows rolled up, or in a small bathroom with six other people), sure you’re gonna smell. But someone smoking a bowl in their backyard and then going for a drive a little while later isn’t going to smell like pot.

You can smell it in some cars as they drive by. Some peoples clothes are so impregnated with it that they reek.

I was following some friends to a party one day. I turned on my AC and could smell the pot smoke coming in through my vents.