Too drunk to drive?
August 18, 2005 1:48 PM   Subscribe

What's a reliable way to tell if you're too drunk to drive?

I'm looking for field tests, not "impairment begins at the first drink" or "if you drive through a convent".
posted by mosch to Travel & Transportation (34 answers total) 1 user marked this as a favorite
Standard field sobriety tests are:

- try to walk in a straight line, heel-to-toe.
- tip his or her head back with eyes closed and try to touch the tip of the nose with the index finger.
- stand on one foot.
- reciting all or part of the alphabet, forwards or backwards.

For me, I generally do the math if I'm worried and estimate conservatively.
posted by jessamyn at 1:54 PM on August 18, 2005

Look around the bar and look for attractive women. If you think every woman you see is at least kinda hot... you are too drunk to drive.
posted by aburd at 1:54 PM on August 18, 2005

My rule is more than one drink and that's it. At 6'4" and >200lbs I could probably get away with two but it's simply not worth getting a driving ban if you miscalculate. If you are actually impaired then who is to say you'll be doing the test right?

Don't take the chance please.
posted by longbaugh at 1:58 PM on August 18, 2005

If you even have to ask yourself if you're ok to drive, don't.
posted by ORthey at 1:59 PM on August 18, 2005

You could score your own breathalizer, but I would think that if you are facing this question, it's likely that you are at risk of incarceration should you be pulled over. If the question is how to determine whether your blood alcohol is .1 or .07 or whatever your local area makes for legally drunk there's no sure fire way which is why even after arrest, the police draw blood for testing.
posted by shagoth at 1:59 PM on August 18, 2005

Not a good question, because the answer IS "impairment begins at the first drink". If you're perfectly sober, you have a non-zero chance of getting into an accident. If you're so drunk you pass out while driving, you have nearly a 100% chance of an accident. As your BAC rises, your chance of getting into an accident rises. I realize that you're looking to do a risk assessment, but there are many variables, of which your BAC is only one. Even if you feel OK one day at one BAC and arrive at your destination safely, the next day may have different distractions, different alertness and awakeness levels, etc. And of course, there's no way to tell if you're going to get into an accident on any given trip, regardless of alcohol impairment.

I guess what you're looking for is what the BAC vs. chance of accident curve looks like, and how to test where you are on it. I suspect for the latter, you could estimate your BAC with a breathalyzer (they aren't that expensive) or by calculating based on your body weight and what and when you've consumed.
posted by trevyn at 2:00 PM on August 18, 2005

You could always buy a pocket breathalyzer.
posted by nitsuj at 2:02 PM on August 18, 2005

The cheapest breathalyzer on is $39, here's a full list of what they have.

I don't have one but I've estimated that for me 'pretty drunk' is a lot less then 0.8, and 0.8 is not actualy very dangerious. Equivilant to driving with a cellphone, or driving over the age of 70.
posted by delmoi at 2:05 PM on August 18, 2005

arg, the link didn't work, for some reason Just search for "breathalyzer" on amazon.
posted by delmoi at 2:06 PM on August 18, 2005

- try to walk in a straight line, heel-to-toe.
- tip his or her head back with eyes closed and try to touch the tip of the nose with the index finger.
- stand on one foot.
- reciting all or part of the alphabet, forwards or backwards.

That won't help you stay out of jail if you have a high tolerance.
posted by delmoi at 2:07 PM on August 18, 2005

Agree with ORthey.

If you're not sure, take a cab.

Even if you're under the legal limit you know you're buzzed.
posted by UncleHornHead at 2:08 PM on August 18, 2005

Too busy to source, but the sane (non-MADD) argument cites studies that say that substantial impairment begins around .12 BAC.

delmoi, I think you mean .08
posted by Kwantsar at 2:13 PM on August 18, 2005

I usually try the hand slap test. You hold your hands out, palms down. Your (sober) friend places his hands under yours, palms up. He tries to quickly move his hand from under yours and slap the top, before you can pull away. If he misses 4 times in a row, I can drive. If not, he gives me back my keys.
posted by darkness at 2:15 PM on August 18, 2005

Dude those breathalizers suck donkey balls. I bought one from Sharper Image ('cause my girlfriend worked there...) and we played around with it drinking one night on the couch. The thing would routinely give is results that would differ +/- .04% - that's a huge difference when the limit here in Oregon is .08%!

By the way the greatest thing about Sharper Image (well, maybe the only good thing...) is that they have a no-questions-asked return policy. Played with it for a night, returned it when it was determined it was a piece of crap.

As it turns out, a buddy of mine had one from another store too. Same thing with that one. They're like joke condoms. Fun to have (I guess...) but not for actually using.
posted by pwb503 at 2:41 PM on August 18, 2005

Do some physical exercise. See what 10 push ups feel like, or a brisk run around the block. Try to do some math, or write a coherent sentence. Impairment will demonstrate itself if it is present.
posted by buzzman at 2:48 PM on August 18, 2005

The wisdom generally cited here in Australia is that by the time you hit the legal limit (0.05) your reaction time is already doubled.

The math over here for staying under the limit is taught:
Men: 2 drinks in the first hour. 1 drink per hour after that.
Women: 1 drink in the first hour. 1 drink/hour after that.

No garauntees, of course, YMMV, and (to coin the advertising jingle):

Don't drink and drive. You're a bloody idiot.
posted by coriolisdave at 2:55 PM on August 18, 2005

I simply do not drive if I've had even one drink. This has nothing to do with impairment, but rather because this city has an overzealous DUI taskforce and will lock you up for the night just because they feel like it.

One Miller Lite an hour and a half ago? They claim they can't accurately assess the risk you pose to the public and would rather you sort it out with the judge later.

Fortunately, I live a block away from all the good clubs in town. This is extra fortunate as I get to drink for free most every evening at my (almost) nightly gigs.
posted by sourwookie at 3:21 PM on August 18, 2005

Does clicking best answer on almost every reply mean you are too drunk to be using Ask Metafilter?
posted by matildaben at 3:31 PM on August 18, 2005

[fixed delmoi's link to breathalyzers on amazon]
posted by jessamyn (staff) at 3:53 PM on August 18, 2005

Yes, impairment begins at the first sip. There's no single point where you're "unsafe enough" to worry about, it's a gradient. I myself wouldn't want to increase my risk of a crash by more than about 5%, or less, and that's much less than what a single beer does, provably.
posted by abcde at 3:53 PM on August 18, 2005

  1. Get out of the car.
  2. Stretch out your arms and touch your nose with your finger.
  3. Now walk this white line.
  4. HALT! Come back.
  5. On your hands!
  6. One hand!
  7. Now do a rollover, turnover and flip-flop!
  8. Alright. [Throws him juggling pins.] Now juggle these, do a tap dance and sing the Catalina Magdalena Luptenschteiner Volunbeiner song!
God damn your drunk driving tests are hard!
posted by kirkaracha at 3:54 PM on August 18, 2005

Worked a detail at a prosecutors office that brought in DUI cases. We had a demo of the tests. The horizontal gaze nystagmus test was considered the most accurate. This site is a drunk drivng defense attorney's, but it seems to describe the test the way I remember it. I think you'd need someone reasonably sober to administer the test for you, but its physiological rather than a skill, so I believe its pretty accurate.

I wonder if abcde means probably or provably, as in prove-able. Regardless, having a driver is the best option if you're drinking.
posted by 3rings at 4:08 PM on August 18, 2005

Okay, this link is the fixed link to the DUI attorney's site. The nystagmus test description is about 4/5 of the way down.
posted by 3rings at 4:11 PM on August 18, 2005

Make sure the person doing the horizontal gaze nystagmus test tries doing it on you a few times when you're sober so they know what they are looking for. You may also naturally fail the test in your sober state, I've heard of people not doing this test.

Get This "breathylzer", I use quotes because breathlyzer is a brandname, the generic name is digital alcohol detector and this one is called Alcohawk. If you're young and have competitive friends it's not the best thing to have around, getting a bunch of guys together with alcohol and a way to quantitatively measure how drunk they are -- awesomely dangerous. The price is $99.99, but as stated above those palm detectors suck. The magic words you are looking for are DOT and/or NTSA approved (which this claims to be). This will be accurate down below a percent. The reason this probably isn't what the cops use is because the difference between .082 and .078 is a DUI.

DUI laws can be pretty baffoon-ish. You can be .06 and by failing the field sobriety test will probably still be charged. As any good lawyer will tell you, never do the FST and never consent to anything. If you think you're over the limit just refuse to any tests, you'll have your license revoked for a year but have a higher possibility of avoiding a DUI (they lack nearly all evidence against you), a good lawyer could help you avoid prosecution. This is all from lawyer friends, but use at your own risk.
posted by geoff. at 5:24 PM on August 18, 2005 [1 favorite]

A friend of mine who was once a semi-professional juggler claims you can be blitzed and still juggle pretty effectively. Having heard that, I've always tended to err on the side of caution.
posted by kimota at 5:28 PM on August 18, 2005

I can juggle while blitzed. I can also transpose most jazz standards into "singer keys" on-the-fly while drunk.

So don't get fooled by a lack of impairment cuz the cops don't care.
posted by sourwookie at 5:42 PM on August 18, 2005

My metric:
It's just not worth the potential consequences.

I might have a beer and drive an hour later. More than that and, no. I'd probably have to kill myself if I killed someone because I chose to drink and drive. And it is always a choice.
posted by five fresh fish at 5:48 PM on August 18, 2005

geoff, if anyone you know has nystagmus while sober and have not been spinning around or pouring cold water into one of their ears, they need to see a neurologist. /OT
posted by LittleMissCranky at 5:57 PM on August 18, 2005

LittleMissCranky, that was told to me by a cop, but it looks to me like an untrained person can confuse several things as a failure when in reality they're not. A trained person will not see it as a failure of the test. So I guess the moral is if you're not trained to do it, don't do it.
posted by geoff. at 6:31 PM on August 18, 2005

Agree with jessamyn on doing the math if you're worried. This means actively remembering how many you've had, which requires paying attention to what's in your glass, which may help keep you from drinking too much when you intend to drive. lso remember to take note if your friendly bartender gives you an extra-generous pour.

Needless to say, if you can't remember how many you've had or are having trouble with the math, you should probably play it conservative and wait a lot longer before driving. A
The part where mosch is not looking for "impairment begins with the first drink" perhaps isn't visible to all?" /grumble
posted by desuetude at 7:57 PM on August 18, 2005

I meant as in "prove-ably." It's a real word, of course.
posted by abcde at 10:06 PM on August 18, 2005

My simple answer:

If you have to ask yourself the question, "am I sober enough to drive?" it probably means you're not.

When there's even a question, why risk it?
posted by generichuman at 10:06 PM on August 18, 2005

One thing to remember is that effects like slower reaction time may appear before you actually "feel drunk". This won't affect your interaction with humans but when you're driving, even a slight time difference in you reacting to events on the road can mean an accident. Don't risk it. You are putting other lives at risk.
posted by madman at 10:59 PM on August 18, 2005

An offensive story in which a portable breathalyzer spurs people to drink more, not less.

The California DMV, among others, hands out little cards with these sorts of Blood Alcohol Concentration charts on them. This is the right way to know if you're too drunk to drive, by the way. Your average liver can metabolize 1 drink per hour.

Bear in mind that horizontal gaze nystagmus is variable and is hard to see, especially if you don't know what you're looking for. The person administering the test cannot be drunk, or they risk misquantifying the amount of observed nystagmus - it's a subtle finding. It's also caused by some medicines, including certain anticonvulsants.
posted by ikkyu2 at 11:25 PM on August 18, 2005

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