# Can cops really make you do this? (police powers of persuasion) **URL:** \ **Category:** Factual Questions\ **Created:** [October 13, 2004, 1:27am UTC](https://boards.straightdope.com/t/can-cops-really-make-you-do-this-police-powers-of-persuasion/268923 "2004-10-13T01:27:55Z")\ **Posts on this page:** 20\ **Page:** 3
**Author:** ![Loach](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/loach/32/350_2.png) [@Loach](https://boards.straightdope.com/u/Loach)\ **Post date:** [October 14, 2004, 8:37pm UTC](https://boards.straightdope.com/t/can-cops-really-make-you-do-this-police-powers-of-persuasion/268923/41 "2004-10-14T20:37:18Z")
> [@](#): > > Also, following up on Una and TommyTutone’s excellent comments, at what point am I under arrest and booked? If I fail the line-walking buffoon test, am I read my rights and booked or does this not happen until the official Breathalyzer results are in? I’m thinking in terms of my (bum bum) Permanent Record. Will a deep background check show I failed the tightrope-style linewalk trap or is everything forever thrown out when the station’s machine clears me? A good rule of thumb: once they put the cuffs on you consider yourself under arrest. You are arrested for driving while under the influence of drugs and or alcohol \*and/or \* have a blood alcohol content of .08 % or higher. The gist is that they need to prove impairment or BAC. If your BAC is over the limit you are toast. If it is under then it is still possible to prove impairment. For instance if this was the first time you had a drink you will be showing signs of impairment long before you reach the magic number. However, most of the time when the BAC reading comes up lower than the legal limit the prosecutor will not be willing to persue it. Once you are arrested for DWI nothing will get thrown out unless a judge says not guilty. > [@](#): > > I would think if I fail, I am arrested and my car gets towed to the impound lot. What happens if I pass? Does the officer bring me back to my car? Has my car already been towed to the impound lot at this time and I have to pay to get it out? What if damage is done to my car via the towing or via vandals if it is left on the side of the highway? I’d like to know that if I was hauled downtown because a potentially vindictive officer (unlikely, but I’m sure it happens) wanted to make my life difficult, I’m not going to be left hanging financially. This is how it is in NJ. There is a law which compels the police to impound a car used during a DWI for 12 hours. This law was made because a drunk was released, made his way back to his car and killed someone in an accident while he was still drunk. Regardless of the circumstances the tow driver is responsible for the safekeeping of the car, you can sue for damages. You will be responsible to pay for the tow, something like $40 if you get it after 12 hours. If you are found not guilty I guess the judge can order your towing fee returned but I have never seen it. Probably only if you can prove there was absolutely no probable cause. ---
**Author:** ![zamboniracer](https://avatars.discourse-cdn.com/v4/letter/z/e9a140/32.png) [@zamboniracer](https://boards.straightdope.com/u/zamboniracer)\ **Post date:** [October 14, 2004, 9:25pm UTC](https://boards.straightdope.com/t/can-cops-really-make-you-do-this-police-powers-of-persuasion/268923/42 "2004-10-14T21:25:55Z")
In Ohio the defense attorneys rcently used to recommend NOT taking the breath test, even with the implied consent automatic suspension penalties, because Ohio has a two tiered drunk driving statute. That is, the penalties for driving with a blood alcohol level over 0.159% were more severe than they were at 0.08%. The logic of refusing the test being that the implied consent penalty was limited to the lower tier level penalty, so why risk taking the test and getting a higher penalty. The powers that be changed the law again to try to take away that tiny loophole but off the top of my head I don’t recall what the new law says. ---
**Author:** ![Loach](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/loach/32/350_2.png) [@Loach](https://boards.straightdope.com/u/Loach)\ **Post date:** [October 14, 2004, 9:35pm UTC](https://boards.straightdope.com/t/can-cops-really-make-you-do-this-police-powers-of-persuasion/268923/43 "2004-10-14T21:35:43Z")
> [@](#): > > In Ohio the defense attorneys rcently used to recommend NOT taking the breath test, even with the implied consent automatic suspension penalties, because Ohio has a two tiered drunk driving statute. I guess that makes sense in a way. It does take away any chance to be found not guilty. If the machine is later found to have a malfunction or if your lawyer proves that the test was given improperly then the whole thing can get thrown out. A refusal takes away all of your defenses. ---
**Author:** ![Badge](https://avatars.discourse-cdn.com/v4/letter/b/4bbf92/32.png) [@Badge](https://boards.straightdope.com/u/Badge)\ **Post date:** [October 15, 2004, 4:12am UTC](https://boards.straightdope.com/t/can-cops-really-make-you-do-this-police-powers-of-persuasion/268923/44 "2004-10-15T04:12:27Z")
> [@TommyTutone](#): > > **Badge** , since you are in here, let me ask you this: according to the drunk driver lawyer guy on the radio, you should refuse to take the dexterity tests on the side of the road because they are designed to make you fail. The tests are not designed to make you fail - they are designed to determine if you are under the influence. They were developed with a lot of scientific research. The tests aren’t looking for perfect balance or a great deal of dexterity. The main thing that I’m looking for are your ability to follow simple instructions and to concentrate on more than one task at a time (such as counting steps out loud while walking the straight line). A sober person can do these things while an intoxicated person will find them quite difficult. Also, the test on which I rely most heavily is the Horizontal Gaze Nystagmus. This test is nearly foolproof, and I can tell by the movement of your eyes almost exactly what your BAC level is. This test is unaffected by how nervous you are and you can’t learn how to beat it, since it tests involuntary muscle movement. > [@](#): > > I assume I am then taken ‘downtown’ to take the actual breathalyzer. I would think if I fail, I am arrested and my car gets towed to the impound lot. What happens if I pass? If I’ve taken you “downtown”, then I already had probable cause to believe that you were driving while impaired and arrested you. So, regardless of the results of the BAC test, you will still be charged with DUI, you are still responsible for the tow bill, etc. At least in Washington, there are two routes to a DUI charge and conviction: either you are over the legal limit (even if you are a conditioned drinker and aren’t actually impaired at that level), or you are impaired (even if you’re under the legal limit). This happened to me exactly once in my 18 years on the job (this was before I learned how to admister the Gaze Nystagmus test). I stopped a car that was weaving all over the road and ran a stop sign. The driver could barely stand and failed miserably at the field sobriety tests. Yet he only blew .078 on the breathalyzer (the legal limit was .10 at the time - it is now .08). He told me that he had two beers on an empty stomach and hadn’t touched alcohol in ten years. He was still charged with DUI (though there was an eventual plea bargain to negligent driving). ---
**Author:** ![zamboniracer](https://avatars.discourse-cdn.com/v4/letter/z/e9a140/32.png) [@zamboniracer](https://boards.straightdope.com/u/zamboniracer)\ **Post date:** [October 15, 2004, 11:58am UTC](https://boards.straightdope.com/t/can-cops-really-make-you-do-this-police-powers-of-persuasion/268923/45 "2004-10-15T11:58:19Z")
> [@Badge](#): > > Also, the test on which I rely most heavily is the Horizontal Gaze Nystagmus. This test is nearly foolproof, and I can tell by the movement of your eyes almost exactly what your BAC level is. This test is unaffected by how nervous you are and you can’t learn how to beat it, since it tests involuntary muscle movement. The HGN test is psuedo-science akin to voo-doo, but that’s just my humble opinion. ---
**Author:** ![Loach](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/loach/32/350_2.png) [@Loach](https://boards.straightdope.com/u/Loach)\ **Post date:** [October 15, 2004, 12:56pm UTC](https://boards.straightdope.com/t/can-cops-really-make-you-do-this-police-powers-of-persuasion/268923/46 "2004-10-15T12:56:46Z")
> [@](#): > > The HGN test is psuedo-science akin to voo-doo, but that’s just my humble opinion. Which would be wrong. The test does not assign any numerical value to the results. It is used to give probable cause. The results of the HGN are then verified by the breathalyzer results. I have never seen a sober person fail the test or an intoxicated person pass. I have also seen people in a classroom setting go from sober to intoxicated. The results are astounding. **Badge** didn’t I just say the same things you did? Ok maybe you said it better. ---
**Author:** ![mks57](https://avatars.discourse-cdn.com/v4/letter/m/b9bd4f/32.png) [@mks57](https://boards.straightdope.com/u/mks57)\ **Post date:** [October 15, 2004, 1:51pm UTC](https://boards.straightdope.com/t/can-cops-really-make-you-do-this-police-powers-of-persuasion/268923/47 "2004-10-15T13:51:10Z")
> [@Loach](#): > > Which would be wrong. The test does not assign any numerical value to the results. It is used to give probable cause. The results of the HGN are then verified by the breathalyzer results. I have never seen a sober person fail the test or an intoxicated person pass. I have also seen people in a classroom setting go from sober to intoxicated. The results are astounding. According to the published test data, the HGN test has a fairly high false-positive rate (16%), and that’s assuming that it was administered properly. ---
**Author:** ![Loach](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/loach/32/350_2.png) [@Loach](https://boards.straightdope.com/u/Loach)\ **Post date:** [October 15, 2004, 3:21pm UTC](https://boards.straightdope.com/t/can-cops-really-make-you-do-this-police-powers-of-persuasion/268923/48 "2004-10-15T15:21:56Z")
> [@](#): > > According to the published test data, the HGN test has a fairly high false-positive rate (16%), and that’s assuming that it was administered properly. 16% seems pretty damn good to me. Remember we are not talking about using it as a sole reason for a conviction or even the sole reason for an arrest. It is one tool for finding probable cause for an arrest. You have to look at the totality of the circumstances for that. I will assume that 16% is correct even though I have never seen a false positive. If the only evidence I had was the HGN then I would wonder if the guy had a head injury or some physical defect which causes his eyes to slam into the side of his skull repeatedly. This has never been the case with me but I’m sure it happens sometime. Generally you have most or all of the following: a strong odor of an alcoholic beverage, slurred speach, fumbling with his documents, lack of balance, inability to tell you where he is or what time it is (off by hours), watery eyes, failure of the walk and turn, failure of the one leg stand and many others. I would like to see what the false positive rate is when you use the three tests recommended by the NTSB and not just the HGN. ---
**Author:** ![chula](https://avatars.discourse-cdn.com/v4/letter/c/a4c791/32.png) [@chula](https://boards.straightdope.com/u/chula)\ **Post date:** [October 15, 2004, 4:18pm UTC](https://boards.straightdope.com/t/can-cops-really-make-you-do-this-police-powers-of-persuasion/268923/49 "2004-10-15T16:18:10Z")
> [@Badge](#): > > This happened to me exactly once in my 18 years on the job (this was before I learned how to admister the Gaze Nystagmus test). I stopped a car that was weaving all over the road and ran a stop sign. The driver could barely stand and failed miserably at the field sobriety tests. Yet he only blew .078 on the breathalyzer (the legal limit was .10 at the time - it is now .08). He told me that he had two beers on an empty stomach and hadn’t touched alcohol in ten years. He was still charged with DUI (though there was an eventual plea bargain to negligent driving). The breathalyzer showed he was significantly under the legal limit and he was still arrested?? ---
**Author:** ![Loach](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/loach/32/350_2.png) [@Loach](https://boards.straightdope.com/u/Loach)\ **Post date:** [October 15, 2004, 4:32pm UTC](https://boards.straightdope.com/t/can-cops-really-make-you-do-this-police-powers-of-persuasion/268923/50 "2004-10-15T16:32:07Z")
> [@chula](#): > > The breathalyzer showed he was significantly under the legal limit and he was still arrested?? He wasn’t _still_ arrested, he was arrested before the breathalyzer was administered due to probable cause such as failing the tests, falling down…(see above). The legal limit is the point designated by the legal system where everyone is going to be impaired enough that they should not be driving. Whether the limit is set too high or too low is for GD and has been discussed there many times. Someone can be impaired below the limit, such as someone not used to drinking. The laws in the states I know about say something to the effect of being impaired by drugs/alcohol \*\*\*AND/OR \* \*\* have a BAC of .08% or higher. If the arresting officer can prove impairment with evidence such as his testimony, video tapes etc then the driver may be found guilty. In reality prosecutors don’t want to touch any case involving a reading below the limit and will plea bargain it down to a reckless driving ticket. ---
**Author:** ![Badge](https://avatars.discourse-cdn.com/v4/letter/b/4bbf92/32.png) [@Badge](https://boards.straightdope.com/u/Badge)\ **Post date:** [October 15, 2004, 6:51pm UTC](https://boards.straightdope.com/t/can-cops-really-make-you-do-this-police-powers-of-persuasion/268923/51 "2004-10-15T18:51:10Z")
> [@zamboniracer](#): > > The HGN test is psuedo-science akin to voo-doo, but that’s just my humble opinion. What is the basis for your opinion on this? My reliance on the test is based on the scientific studies that back the training and my own experiences using it in the field for over 10 years. The Horizontal Gaze Nystagmus test has been accepted by the courts (only for probable cause, of course). And as I said, I’ve never seen it fail. Not once. I have never once had a “false positive” nor a “false negative”. ---
**Author:** ![Badge](https://avatars.discourse-cdn.com/v4/letter/b/4bbf92/32.png) [@Badge](https://boards.straightdope.com/u/Badge)\ **Post date:** [October 15, 2004, 6:55pm UTC](https://boards.straightdope.com/t/can-cops-really-make-you-do-this-police-powers-of-persuasion/268923/52 "2004-10-15T18:55:01Z")
> [@chula](#): > > The breathalyzer showed he was significantly under the legal limit and he was still arrested?? Actually, he was arrested long before the breathalyzer test was administered. The arrest occured in the field, after he was stopped for being unable to drive correctly and then completely failing the field sobriety tests. As I said before, there are two ways to be guilty of DUI (at least in Washington State). Either you are over the legal limit (regardless of how impaired you are) or you are impaired (regardless of your BAC level). ---
**Author:** ![chula](https://avatars.discourse-cdn.com/v4/letter/c/a4c791/32.png) [@chula](https://boards.straightdope.com/u/chula)\ **Post date:** [October 15, 2004, 7:09pm UTC](https://boards.straightdope.com/t/can-cops-really-make-you-do-this-police-powers-of-persuasion/268923/53 "2004-10-15T19:09:20Z")
Oops. I should have read that post more carefully before I posted. I wonder how a DUI charge based on the sole evidence that the driver “seemed impaired” could ever stand up. The HGN test was administered to me once, and it was a joke. I was still blinking in the shock of having a bright light suddenly shined in my face when the cop ordered me out of the car. I wouldn’t be surprised if my eye movements appeared “jerky” in those few seconds I was blinking in the light. [Here](http://www.forensic-evidence.com/site/Biol_Evid/HGN.html) is an article on HGN that cites the study with the 16% false positive rate. Seems like we’re getting a bit off-topic. ---
**Author:** ![Loach](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/loach/32/350_2.png) [@Loach](https://boards.straightdope.com/u/Loach)\ **Post date:** [October 15, 2004, 7:21pm UTC](https://boards.straightdope.com/t/can-cops-really-make-you-do-this-police-powers-of-persuasion/268923/54 "2004-10-15T19:21:47Z")
> [@](#): > > I wouldn’t be surprised if my eye movements appeared “jerky” in those few seconds I was blinking in the light. “Jerky” is not at all what HGN measures. Its a very distictive involuntary movement of your eye. Blinking because of a bright light has nothing to do with it. I have administered it day and night, inside and out and I have never seen it fail. ---
**Author:** ![jnglmassiv](https://avatars.discourse-cdn.com/v4/letter/j/f07891/32.png) [@jnglmassiv](https://boards.straightdope.com/u/jnglmassiv)\ **Post date:** [October 15, 2004, 7:28pm UTC](https://boards.straightdope.com/t/can-cops-really-make-you-do-this-police-powers-of-persuasion/268923/55 "2004-10-15T19:28:37Z")
Great article, **Chula**. It really illustrates the psuedoscience point. Some choice quotes: > [@](#): > > The consumption of common substances such as caffeine, nicotine, or aspirin also lead to nystagmus almost identical to that caused by alcohol consumption. and > [@](#): > > The NHTSA manual recommends removal of all contact lenses. and > [@](#): > > NHTSA claimed an accuracy rate for the combined procedure [Jngl: the linewalk and HGN tests] of 82 percent, with 16 percent false positives and 1 percent false negatives. ---
**Author:** ![mks57](https://avatars.discourse-cdn.com/v4/letter/m/b9bd4f/32.png) [@mks57](https://boards.straightdope.com/u/mks57)\ **Post date:** [October 15, 2004, 7:31pm UTC](https://boards.straightdope.com/t/can-cops-really-make-you-do-this-police-powers-of-persuasion/268923/56 "2004-10-15T19:31:11Z")
> [@Badge](#): > > The Horizontal Gaze Nystagmus test has been accepted by the courts (only for probable cause, of course). And as I said, I’ve never seen it fail. Not once. I have never once had a “false positive” nor a “false negative”. Even the most optimistic studies don’t claim that the test is 100% reliable. See [http://www.nhtsa.dot.gov/people/injury/alcohol/SFST/appendix\_a.htm](http://www.nhtsa.dot.gov/people/injury/alcohol/SFST/appendix_a.htm) ---
**Author:** ![Loach](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/loach/32/350_2.png) [@Loach](https://boards.straightdope.com/u/Loach)\ **Post date:** [October 15, 2004, 7:32pm UTC](https://boards.straightdope.com/t/can-cops-really-make-you-do-this-police-powers-of-persuasion/268923/57 "2004-10-15T19:32:38Z")
I’ll try to clear that up. While HGN does measure what you can call “jerks” of the eye, what you describe does not apply. Blinking because of a change in light is not the same. If you saw it yourself you would be astounded how the eye moves when the person is intoxicated. BTW when you were given the test did you pass? Were you drunk? > [@](#): > > wonder how a DUI charge based on the sole evidence that the driver “seemed impaired” could ever stand up. Two answers to that. The easy answer is they usually don’t. But that is because prosecutors don’t feel confident enough to proceed, not that there would be anything wrong with the charge or going to trail without a BAC reading. The other answer is if you as a private citizen were the only one testifying that the guy “seemed impaired” then it wouldn’t stand. If a police officer who is trained to recognize impairment and has years of experience, then his testimony has greater weight. Of course the defense attorney then can try to pick apart the expert testemony. Its harder to argue with a machine. ---
**Author:** ![Loach](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/loach/32/350_2.png) [@Loach](https://boards.straightdope.com/u/Loach)\ **Post date:** [October 15, 2004, 7:42pm UTC](https://boards.straightdope.com/t/can-cops-really-make-you-do-this-police-powers-of-persuasion/268923/58 "2004-10-15T19:42:32Z")
The article cited has the conclusion that HGN is a valid tool that can be used to tell if someone is impaired but should not be used to try to predict an actual BAC. Basically what I have been saying. Its used as part of the totality of the circumstances, not a stand alone test. ---
**Author:** ![jnglmassiv](https://avatars.discourse-cdn.com/v4/letter/j/f07891/32.png) [@jnglmassiv](https://boards.straightdope.com/u/jnglmassiv)\ **Post date:** [October 15, 2004, 7:58pm UTC](https://boards.straightdope.com/t/can-cops-really-make-you-do-this-police-powers-of-persuasion/268923/59 "2004-10-15T19:58:33Z")
> [@Loach](#): > > Its used as part of the totality of the circumstances, not a stand alone test. But it does stand alone. Like you said, the Breathalyzer isn’t needed to make the conviction. The conviction can be based solely on your testimony of a failed HGN. That the prosecutor doen’t want to bring the DUI/DWI case to trial isn’t relevant. The arrest sticks to your record, not to mention the reckless driving arrest/citation. ---
**Author:** ![alice\_in\_wonderland](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/alice_in_wonderland/32/176_2.png) [@alice\_in\_wonderland](https://boards.straightdope.com/u/alice_in_wonderland)\ **Post date:** [October 15, 2004, 8:18pm UTC](https://boards.straightdope.com/t/can-cops-really-make-you-do-this-police-powers-of-persuasion/268923/60 "2004-10-15T20:18:54Z")
> [@jnglmassiv](#): > > But it does stand alone. . It stands alone as _probable cause_ for a serch, stop, arest. It’s NOT used alone for conviction, at least acording to every single post in this thread by someone who administers it. [Previous page](https://boards.straightdope.com/t/can-cops-really-make-you-do-this-police-powers-of-persuasion/268923.md?page=2) [Next page](https://boards.straightdope.com/t/can-cops-really-make-you-do-this-police-powers-of-persuasion/268923.md?page=4)