A sleepy driver is said to be as bad as a drunk driver. Based on my limited personal experience, I tend to agree. Now obviously, a sleepy driver won’t get a reading on a breathalyser, but should a sleepy driver be able to pass a field sobriety test? Is the hassle of being pulled over enough to wake someone up to the point where you don’t look sleepy? If a cop sees an erratic driver and pulls him over thinking he is drunk but then discovers he is not and suspects he is just sleepy, is there anything he can do to prevent that driver from continuing?
Should, or could? There’s no reason why one sleepy person might “pass” a “field sobriety test,” and another will “fail” it. For that matter, even a non-sleepy, sober, person might “fail” the “field sobriety test,” just as intoxicated people sometimes “pass” one–some people are more coordinated than others. The evaluation of someone’s performance on these tasks is highly subjective, and the “test” is not really given to actually determine if a person is drunk.
A friend of mine who once worked for the DEA told me that a “field sobriety test” is just a pro forma procedure that cops use to bolster their report should a charge of drunk driving go to trial. In fact, an experienced cop uses only one observation to determine whether to go on to an arrest and a Breathalyzer test: the pupils of the driver’s eyes. All the other stuff is a way to have “probable cause.”
In California, at least, it is technically illegal for a person to drive when s/he is in any unsafe condition. So technically, the person could be arrested for reckless driving, but I doubt this ever happens because “unsafe,” in this case, is such a subjective call, and legally difficult to determine.
I suppose, however, for civil damages in the case of an accident, a cop’s testimony might matter. And if a person ever has a seizure, the hospital has to report it to the DMV, and that can affect that person’s driving privileges. (The key word here is “privilege,” not “right.”)
My brother in law is a city cop and he told me the exact same thing, and at least in the state in question (West Virginia) a driver is NOT required as part of the implied consent law to perform field sobriety tests (breath tests are required). So his advise to me was to never, ever, ever, ever perform a field sobriety test even if 100% sober, because you will “fail” the test.
I can’t imagine what a DEA agent knows about field sobriety tests.
If officers are using the nationally accepted Standardized Field Sobriety tests, they are actually very accurate and well-backed by scientific testing. By administering the three standard tests, I can easily tell if someone is above or below the legal limit. If someone passes the tests, they will be sent on their way.
The three tests are: Horizontal Gaze Nystagmus (this looks for involuntary movements of the eyes, not the condition of the pupils), the Walk and Turn test and the One-leg Stand test. The tests not only look at coordination and balance, but on the ability of the subject to follow instructions and to concentrate on more than one thing at a time.
There are some other optional tests I may use sometimes (usually if the person has a physical problem that prevents them from doing the balance tests), plus I can use a portable breath testing device. Combining the results of the tests with other information, such as odor of intoxicants, admissions to drinking, the observed driving, bloodshot eyes, etc., all combine to provide enough probable cause to make an arrest.
As far as the OP, I don’t think a tired person would have a problem passing the tests. They may have been nodding off while driving, but after being stopped I imagine they would be wide awake!
I agree that taking the field sobriety tests is just giving evidence to the officer, and if you’ve been drinking then you would be wise to refuse to take the tests.
However, if your BIL says that even a sober person will fail the tests, then he either doesn’t know what he’s doing or he’s crooked. The test are accurate if done right and a sober person will pass the tests.
I was once pulled over by a cop when I was driving home after an all night dance (no alcohol). I was tired and weaved a bit. He came up to the car, quickly realized I was tired and not drunk, and sent me on my way once he found out I had about 20 minutes left to go. He suggested that next time I take a nap before driving. I was completely awake for that 20 minutes 
but conked out as soon as I got home.
Anecdote: I once fell asleep driving on the motorway, swerved into the other lane and hit a car. Having stopped safely (with little damage and no injury to anybody, I was extremely lucky) and exchanged insurance details with the other driver, I was more than awake enough to continue my journey home. I imagine that being pulled over by the cops would produce a similar reaction.
So you are saying that there is no other possible wordly reason that a person could lose their balance walking a straight line other than being intoxicated?
Most of his friends are cops, and he teaches a DUI class.
But one single failure isn’t enough to support DUI. Drunks don’t just lose their balance once… they’re often totally unable to stay on the line at all. Some of them can’t even stay on their feet! If you stumble but otherwise act normally and pass all the other tests, a cop is going to chalk it up to nerves or clumsiness.
Even if the cop was going to be a real jerk about a small mistake, he’d never have blood or breath tests confirm the presence of alcohol and you’d have a good case in court.
This is one of the main points of my question. A cop sees a guy all over the place, assumes him drunk and pulls him over. That should be enough to wake him into alertness. Then the cop has nothing to prove the guy was falling asleep at the wheel (well, video, I guess) and the guy is sober, of course.
What recourse would a cop have to make a case for a guy being dangerously sleepy?
My lawyer once told me that roadside tests are akin to testifying against yourself, and advised me to always refuse them no matter the situation. Yes, it means you’ll be taken down to the station for a breathalyzer – but he said that in almost every case, the officer has already decided to make the arrest anyway before requesting the tests. They exist for the sole purpose of gathering evidence against you, are you are in no way compelled to comply.
The magic words: “Sir (or ma’am), I respectfully decline to perform any roadside tests.”
Regarding the OP, I was once pulled over for crossing a lane line when I was completely sober, but very tired. Thinking it would get me off the hook, I agreed to the tests and was arrested anyway. I was cuffed and taken to the station, where I blew a 0.0, got released and driven back to my car without so much as a “my bad.” Had I known the magic words above, the outcome would have been the same but I would have saved myself the humiliation of standing on one foot on the side of the road as cars drove by honking at me.