Field Sobriety Tests
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What is a Field Sobriety Test?
Standard field sobriety tests were developed years ago by the NHTSA (National Highway Traffic Safety Administration). They were designed to detect impairment among drivers on the roadways. There are three standard FST’s:
- One-Leg Stand. As the name suggests, this test has the subject stand on one leg with the other leg approximately 6 inches from the ground, for about half a minute. The test is designed to detect balance problems. Those problems may reveal themselves in swaying, needing your arms to balance, and other indicators.
- Walk and Turn. This is probably the most commonly shown test and requires that you walk a specified number of steps in a particular way, then turn 180° and walk back in the other direction. The test supposedly measures not only your ability to walk a line without staggering, but also your ability to follow directions while performing the test.
- HGN. This stands for Horizontal Gaze Nystagmus. HGN is an eye movement that is involuntary. According to the NHTSA, it is exaggerated in those who are intoxicated. HGN is measured during an FST by asking you to track a light held by the officer.
Additional tests sometimes used are the “finger to nose” test, reciting the alphabet, and even reciting it backwards; these are not part of the standard FST’s.
The NHTSA claims the standard FST’s are useful and that if enough indicators are seen by the officer, it means there is a probability that you have a blood alcohol content (BAC) of 0.08 or higher, currently the legal limit in all states, including Arizona.
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Am I Legally Required to Submit to Field Sobriety Tests?
The short answer is that there is no law in Arizona requiring you to perform field sobriety tests. The downside of a refusal, however, is that you likely will be arrested for DUI immediately upon your refusal, and the officer will request that you take a chemical test. Even if you refuse the chemical test (exposing yourself to loss of your driver’s license), the officer will likely apply for and obtain a search warrant for the chemical test. Moreover, the prosecutor will use your refusal as evidence that you were impaired at the time.
Defending Field Sobriety Test Results
Assuming you perform the field sobriety tests, and the officer arrests you for drunk driving, there are a number of potential points of attack against the FST results:
- FST results are subjective. The field sobriety tests, unlike a blood test or even a breathalyzer, do not involve a mathematical or chemical measuring process. The results rely upon the subjective interpretation of the officer administering the test. Given the fact that prior to performing the test the officer has probably decided, at least in his own mind, that you are guilty of DUI, there is an overwhelming chance that he will interpret the FST results in a way that supports that conclusion.
- FST’s are often improperly administered. Many police officers make DUI stops. Not all are qualified to administer or interpret FST’s.
- Medical and physical conditions can affect FST results. There are a host of medical conditions and medications that can affect the results of a field sobriety test. Lack of coordination can also lead to false results, as can environmental factors.
The fact that an officer says you’ve failed the FST’s is simply evidence in your case. That evidence can be challenged successfully in many cases. If you are facing a DUI charge, contact The Feldman Law Firm to speak to an experienced DUI lawyer. We understand how to spot weaknesses in a DUI prosecution, including the claim that you have failed the field sobriety tests. Call us for a free consultation.