Types of Field Sobriety Tests Used by Arizona Law Enforcement

When a police officer pulls someone over for suspicion of driving under the influence of alcohol or drugs, the officer may perform field sobriety tests (FSTs) on the driver before administering a breath or blood test. Officers use field sobriety tests to determine, in their opinion, whether someone is intoxicated. If the officer believes that a driver is impaired, they will then likely conduct a blood or breath test. However, blood and breath tests require that the officer have probable cause to believe that the motorist is intoxicated. Thus, FSTs are a tool police officers use to develop probable cause. There are three common types of Arizona field sobriety tests, described below:

The One-Legged Stand Test: In this FST, an officer will instruct a driver to stand up straight while raising one foot about six inches off the ground. After a few seconds, the officer will then tell the motorist to place their foot back on the ground. The officer is looking for whether the driver loses their balance, uses their arms to keep themselves up, or fluctuates the height of their raised foot.

The Walk-and-Turn Test: For this FST, the officer asks the driver to take nine steps forward, heel-to-toe, before turning around and coming back the same way. This FST tests a motorist’s ability to follow instructions, as well as their balance. Aside from signs of imbalance, cues of intoxication include when drivers take the incorrect number of steps, are unable to negotiate the turn, or otherwise fail to follow the instructions.

The Horizontal Gaze Nystagmus Test: When an officer conducts the horizontal gaze nystagmus test, he holds a pen or other object a few inches in front of the driver’s eyes, moving it from side to side. The officer takes note of any involuntary eye movements as the motorist’s eyes track the moving pen.

Of course, there are many problems with each of these specific FSTs, as well as with FSTs in general. One of the most common criticisms is that FSTs fail to account for certain medical conditions. For example, seizure medications can cause a person’s eye to jerk unpredictably, incorrectly sending an intoxication cue. Similarly, anyone who has suffered physical injury to their legs or feet may have a difficult time completing the walk-and-turn or one-legged stand tests.

Additionally, FSTs require the officer to use his subjective interpretation to determine whether the motorist passed or failed. This introduces the possibility for numerous other errors, further decreasing the effectiveness of FSTs in general.

Have You Been Arrested for an Arizona DUI?

If you have recently been arrested for an Arizona DUI offense, contact Attorney James E. Novak for a free consultation. Attorney Novak is a respected Tempe Arizona DUI lawyer with extensive experience handling all types of drunk driving cases, including extreme DUIs as well as first-time DUIs. Attorney Novak understands how to undermine the prosecution’s case with common sense, legal argument, and, when appropriate, scientific evidence. To learn more about how Attorney Novak can help you defend against the charges you are facing, call 480-413-1499 to schedule a free consultation to discuss your case today.

Additional Resources:

• A.R.S. 28-1381 – DUI Laws
• A.R.S. 28-1382 –Extreme DUI Laws