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Types of Field Sobriety Tests Used in Arizona

Posted on February 27, 2023 in DUI,Field Sobriety Tests

A field sobriety test is a method used by law enforcement to determine if a driver or suspect is under the influence of drugs or alcohol. It is a test that is conducted during a traffic stop and judged solely on the police officer’s opinion. For this reason, field sobriety tests are largely biased, inaccurate and do not hold up in court. It is generally recommended by DUI defense lawyers in Tempe not to take them.

The Horizontal Gaze Nystagmus Test 

Three types of field sobriety tests are approved for use in Arizona by the federal and state government. The first is the horizontal gaze nystagmus (HGN) test. This is a visual test that gauges whether a driver can move his or her eye from side to side without bouncing, jerking or making rapid eye movements (nystagmus). It is typically conducted by requiring a driver to follow a light or object with his or her eyes while the conducting officer watches for incorrect or uncontrollable eye movements.

The HGN test is based on the idea that if a driver is impaired, his or her central nervous system will be unable to control eye muscles, resulting in involuntary movement of the eye during the horizontal gaze nystagmus test. The greater the degree of impairment, the more pronounced the driver’s nystagmus will be. 

The Walk-and-Turn

The walk-and-turn field sobriety test asks a driver to take nine steps, heel to toe, while walking in a straight line. Once the nine steps have been completed, the driver is asked to turn on one foot and return in the opposite direction in the same manner. While the driver is performing the exercise, the officer is instructed to look for signs that are consistent with drug or alcohol impairment. Examples include the inability to follow directions, lack of balance, stopping to regain balance, taking the incorrect number of steps or making an improper turn. 

The One-Leg Stand

As the name implies, a one-leg stand field sobriety test requires a driver to stand with one foot off the ground. The instructions are to stand with one foot approximately six inches from the ground, then remain in this position while counting out loud for 30 seconds. If the driver loses his or her balance, sways while balancing, has to use his or her arms, or puts down his or her foot before 30 seconds have passed, he or she will fail the test.

Should You Refuse to Take a Field Sobriety Test?

As a general rule, you should politely refuse to take a field sobriety test if requested by an officer during a traffic stop. Field sobriety tests are not required and will only serve to strengthen the state’s DUI case against you. Field sobriety tests are generally used as a preliminary to chemical testing, such as a Breathalyzer test in Tempe. Unlike a chemical test, however, you will not be penalized with the loss of your license for refusing to take a field sobriety test in Arizona.

In addition, field sobriety tests are historically inaccurate. Failing one is a distinct possibility, even if you are not under the influence of drugs or alcohol. You may have an injury or disability that prevents you from passing the one-leg stand test, for example, or glaucoma that makes the HGN test difficult. It is generally not worth the risk of potentially failing to agree to take a field sobriety test. 

If you did take a field sobriety test leading up to an arrest, a DUI defense lawyer can help you challenge the results. If you did not understand the directions, your fitness level made you fail the test or you were simply nervous from being questioned by a police officer, your lawyer can argue that the field sobriety test results were inaccurate. For more information about the role that a field sobriety test might play in a DUI case against you, contact an attorney.

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