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What You Need to Know About Field Sobriety Tests

September 24, 2021

Field sobriety tests, or FSTs, are an important tool that officers use to determine if someone is under the influence of drugs or alcohol behind the wheel. Because the penalties for driving under the influence are severe, knowing your rights when you’re asked to take an FST is crucial. What happens during your FST will impact the case against you and could mean the difference between being arrested and going home. Of course, if you are arrested, call a criminal defense attorney right away to protect your rights. Here is what you need to know about FSTs and their role in DUI cases. 

When can an officer request a field sobriety test?

A police officer can pull you over and ask you to submit to an FST any time he or she has probable cause to believe that you may be impaired. Weaving, erratic driving, and common traffic violations all give officers probable cause to suspect a DUI. A police officer may also request an FST if you appear intoxicated after being stopped for a different offense, or if alcohol or marijuana are visible in your car. 

What happens during an FST?

In Arizona, there are three different FSTs that an officer may use. These are:

  • Horizontal Gaze Nystagmus, or HGN, which involves following a pen or other object back and forth, using only your eyes. 
  • Walk-and-Turn, during which you will be asked to take nine steps in one direction then to turn around and take nine steps in the other direction. 
  • One-Leg Stand, which involves standing on one leg for 30 seconds without falling.

The results of these tests are usually reported during criminal proceedings, but officers on the scene may use other types of tests, such as asking you to say the alphabet backwards, to further evaluate your impairment. These other tests are not usually used in criminal cases, but they are conducted to help the officer decide if further investigation is needed. 

Do I have to submit to the test?

Under Arizona law, you do not have to take an FST. You are only required to provide your name, identification, proof of insurance, and vehicle registration during a traffic stop. You can refuse to take the test or answer any other questions the officers may ask. It is a good idea to avoid providing additional information, since it may be used against you later. 

If you do refuse to take the test, the officer will likely arrest you and ask you to take a breathalyzer, blood, or urine test. FSTs are notoriously unreliable—sometimes, sober people cannot pass them—but screening tests are accurate. You can also refuse to take the post-arrest breathalyzer, blood, or urine test, but your driver’s license will be automatically revoked for at least 12 months if you do. 

What factors can impact an FST?

Some people believe FSTs are reliable indicators of impairment because of research that shows them as such. However, it is important to remember that this research was conducted in laboratory settings, not in the real world, where other factors influence the test.

During a field sobriety test, weather, uneven pavement, traffic conditions, and even your footwear can impact your test performance. Additionally, people who undergo FSTs in the real world are usually anxious, which also influences their performance. If you decide to take an FST, be sure to take note of the conditions around you, which could be mitigating factors if the officer determines you didn’t pass the test. 

What should I do if I am arrested for a DUI?

Whether you are arrested on the basis of refusing an FST or you were arrested after failing a test, what you do next is extremely important. Always contact a criminal defense attorney immediately, so that your rights are protected from the very start. Never discuss the case with police officers without your lawyer present. Even if it seems like you could resolve your case by explaining your actions to the officers, anything you say could be misconstrued and used against you. Remain polite with the officers, but don’t answer their questions. 

In Arizona, there are mandatory minimum fines and jail time for DUI offenses, which escalate if you have multiple DUIs. However, a criminal defense attorney can determine if you have mitigating circumstances or other evidence that could help your case. 

Janet Altschuler, Tucson criminal defense attorney, knows the law from both sides, and she brings her knowledge gained during her time as a prosecutor to fight for her clients. If you are arrested, call our law office at (520) 247-1789 for assistance.

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