The Field Sobriety Tests Are Designed To Be Failed:
Several times a day people tell me they passed the field sobriety tests, and the officer nevertheless arrested them. Before discussing the issue, I will point out that I do not believe the results of these tests are indicative of anything. The idea that a person suspected of a crime and under intense pressure will perform well on tests they have never seen is preposterous. In fact, it is shocking how well people do on the tests.
That being said, field sobriety testing is designed to divide a person's attention and then test that person's ability to perform physical dexterity tests. Since driving is a divided attention task, the government claims that these evaluations are predictive of a driver's ability to safely operate a motor vehicle.
Since field sobriety tests are divided attention tests, many of the things that are scored against a person are completely unknown to the test-taker. That is why the testing is so unfair. They are also unfair because in ordinary life we are not tested on anything without the ability to first practice. It is like asking a person to play basketball without first learning the rules and making a few practice shots.
A Few Examples:
In the “Walk and Turn Test" a DUI suspect is placed in what is called the "instructional stance," which has one foot in front of the other. This is an entirely unnatural way of standing, yet the person taking the test is scored one point off if the move or relax before the test begins. Keep this in mind, a suspect fails the Walk and Turn Test if they score two or more points against them. I have yet to meet anyone that understood that they were to remain standing with one foot in front of the other while the officer is demonstrating the test. Some do remain that way, but wouldn't it be far fairer to allow person to see and hear all of the instructions before the scoring begins?
Additionally, if a person wants to practice a few steps, that is also not allowed. In fact, the second instruction is to not start until the officer says to start. Of course, the police officer has done the test hundreds or thousands of times, and a person suspected of DUI is doing the test for the very first time. Nevertheless, practice is not allowed to make perfect in this situation. The DUI suspect gets one chance to get it right.
My point here is not to go over every instruction on the field sobriety tests but to let people know how the unfairness of these tests. There is no way to know if a person has down well on the tests until a qualified DUI Lawyer reviews the evidence.
The Horizontal Gaze Nystagmus test (Eye Test) is not a test of following a pen or finger. People tell me all the time that they passed the eye test and had no trouble following the pen. It is a medical test that looks for an involuntary jerking of the eye that is imperceptible to the person submitting to the test. Alcohol relaxes the muscles in the eye, and as a result, the eye slightly moves when the eye muscles are stressed when taken to their maximum deviation. However, the effect is very subtle and impossible for the test taker to know if he or she is experiencing Horizontal Gaze Nystagmus. As a result, the test-taker cannot know how well they performed on the HGN test.
That being said, the test should never be used in DUI cases because a police officer does not have sufficient medical training to interpret the test properly. There are a myriad of other reasons a person may have Horizontal Gaze Nystagmus, including by not limited to stroke, high blood pressure, prior concussions, and certain medications.
Should a Person Suspected of DUI Ever Submit to Field Sobriety Testing?
I have seen many police officers fail a person on the field sobriety tests, yet the person looked good on video. The fact is, the tests are unfair in every possible measure. They are designed to give a police officer probable cause to make an arrest and then subject a person to chemical testing. No person can possible pass these physical agility tests, even in a controlled classroom setting.