The Role of Field Sobriety Tests in Arizona DUI Arrests

When the police pull you over in Arizona, and they suspect you’re driving under the influence, they’ll ask you to complete a Field Sobriety Test (FST). It’s part of the evidence-gathering process the officers use to build a case against you that lands the DA with the best chance of winning a conviction.

Here’s everything you need to know about FSTs in Arizona.

What are Field Sobriety Tests, and How Does Arizona Use Them?

These are physical and cognitive examinations to ascertain a driver’s level of impairment. Normally, an Arizona law enforcement officer will administer a roadside FST if the officer has probable cause to believe that the driver’s impaired by alcohol or drugs. The tests administered attempt to measure abilities such as balance, coordination, and attention since alcohol and drugs will affect these aspects.

The officers look for obvious signs that the driver is under the influence. If you’re swaying, slurring speech, are late to answer their questions, they consider that probable cause to run the FST and arrest you if you fail it. The test also serves as a setup to get you to submit to taking a breathalyzer test or blood test to further build evidence against you.

Understanding the Three Standardized Field Sobriety Tests

The term “FST” describes three different types of tests conducted by the officers during your detainment on suspicion of driving drunk.

•   The Horizontal Gaze Nystagmus (HGN) – Eye test to check for jerking movements.
•   Walk-and-Turn – A straight-line heel-to-toe walk.
•   One-Leg Stand – Balance test.

These tests are standardized to bring out the physical impairments caused by alcohol. Despite this, performance, however, is dependent on such factors as age or medical conditions, and therefore these factors must be taken into consideration by the officer hen carrying out the FST.

How Can Field Sobriety Tests Indicate Impairment?

The FST isn’t an infallible test, and studies show it’s only accurate in around 70% to 80% of tests administered by officers on the road. Fatigue, anxiety caused by the police pulling the driver over, or a medical condition might be responsible for the driver’s poor performance with the FST.

The HGN test is the most reliable of the three in the eyes of law enforcement and the courts, but it’s still not a 100% accurate test to prove impairment. Arizona courts view FSTs as permissible as evidence in court cases, but they are always challenged by the defendants attorney, and the results are usually thrown out.

Legal Standards of the State of Arizona in the Administration of Field Sobriety Tests

Arizona does not mandate that officers use FSTs in DUI stops. However, if they do use FSTs, it’s expected that they’re done correctly. Officers are educated on how to give FSTs in a uniform and precise manner.

Arizona follows guidelines set by the National Highway Traffic Safety Administration, and imperfect application can void validity in court. What this means is that Arizona has strict DUI laws in which poor FST procedures or officer misinterpretation would be deemed to radially impact a case, providing a defendant grounds to question the reliability of FST during the process of the trial.

Common Reasons for Failure of Field Sobriety Test

Other than Alcohol Impairment Sometimes, a failed FST does not mean the person is intoxicated. Inner ear infections, balance disorders, or other leg conditions may impact performance. Nervousness can also cause the driver to become unsteady or inattentive.

Fatigue or medication may affect coordination even if neither will necessarily compromise driving skills. Weather conditions and poor instructions or uneven ground may also be blamed. A defense attorney will argue the results of the test, making the statement that an FST doesn’t prove the driver’s intoxication, and that there may be other reasons why the driver failed the test.

Can One Legally Refuse a Field Sobriety Test in Arizona?

Yes, Arizona drivers can legally refuse to submit to FSTs. Unlike tests by breathalyzer or blood, which are subject to implied consent laws, FSTs charge in their entirety appear to be voluntary in nature. On the other hand, refusal may raise suspicion, and an officer may rely on other indicators or may seek further testing.

Field Sobriety Tests versus Breathalyzer Tests

While breath alcohol testing directly measures BAC through a breathalyzer, FSTs measure physical coordination and signs of impairment.

For anyone in Arizona, a BAC level of 0.08% at any given time render that person legally impaired. A breathalyzer provides more objective data than FSTs, since they are interpreted by the officer performing the observation. However, probable cause needs to be established for breath alcohol use, and many officers will start with FSTs to set up the conditions for the test to be legal. Compared to breath or blood tests, FSTs are generally viewed as weaker evidence in court.

Challenging Field Sobriety Test Results in Arizona DUI Defense

In Arizona DUI cases, defendants can contest FST results by pointing out factors that have affected test performance. The most common defenses include arguing improper test administration or saying the state of medical conditions after the arrest affected coordination. Defense attorneys challenge FSTs in DUI Arizona cases, especially if they are the main basis of an arrest.

Police Discretion and the Interpretation of Field Sobriety Tests

Subjective, and based upon the officer’s perception of how a driver performed, FSTs are then vulnerable to that officer’s experience and judgment, as well as the possible biases that a police officer may have. With these present, the courts of Arizona have identified that FST results do indeed differ based on the police discretion involved.

Know Your Rights

When Undergoing a Field Sobriety Test Arizona law grants drivers the right to refuse FSTs, since these tests are generally considered voluntary. Refusal certainly will raise suspicion but doesn’t carry immediate penalties like refusal of a chemical test.

Drivers should understand that an officer may still pursue a DUI charge based on other signs of impairment. The rights outlined above can guide a driver in their decisions during the course of a DUI stop; but your best bet is to call an Arizona DUI attorney immediately.

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