field sobriety test

What Factors Can Impact Results on Field Sobriety Tests?

In a DUI matter, a police officer might subject you to field sobriety tests (FSTs) to measure things such as your balance and physiological responses. What the officer is trying to determine is whether or not you are under the influence of alcohol. If you perform poorly on these tests, the officer could reason that your inability to complete them successfully lends probable cause to a DUI arrest.

The unfortunate thing about this is that FSTs are challenging, even for a sober person. Thus, you may be arrested and charged with a DUI even if you hadn't had one sip to drink before you got behind the wheel.

In this blog, we'll explore various factors that can result in poor performance on FSTs that have nothing to do with alcohol consumption.

The Battery of Field Sobriety Tests

Before examining the non-alcohol-related factors that can affect FSTs results, let's first look at the type of tests you may be subject to.

  • Horizontal gaze nystagmus test (HGN): For this test, the officer will move an object side to side in front of your face. Your task is to track the object with your eyes. The officer will watch your eye movement to see if nystagmus occurs – involuntary jerking of the eye. If you're unable to follow the object or you exhibit nystagmus before normally would occur, the officer may suspect that you're intoxicated.
  • Walk-and-turn: As it sounds, the walk-and-turn test requires you to walk heel-to-toe along a straight line, turn around, and repeat the process. Various types of behavior during this task may suggest to the officer that you've had a few drinks. For example, losing your balance or not touching your heel to your toe may result in a "fail."
  • One-leg stand: During this task, you're required to stand on one leg while counting aloud. The officer will be watching you to see if you exhibit behaviors that suggest intoxication, such as putting your arms out to balance, dropping your lifted foot, or swaying.

Factors that Can Impact FST Results

As you can imagine, doing any of the tests listed in the previous section can be difficult. Even sober, you may struggle to complete any one of the tasks, and various stimuli can impact your performance.

Some non-alcohol-related factors that may lead to a "fail" on one or more of the FSTs include but are not limited to:

  • Health conditions: Having a bad back or knees, injuries, or vision problems, and other medical issues can all contribute to poor field sobriety test performance.
  • Improper environment: When officers are trained in administering FSTs, they learn in "ideal" conditions. However, in the field, conditions are far from ideal. Cracks in the road, uneven pavement, poor weather, and other environmental factors can make it difficult for you to balance or walk a straight line. Even something such as the clothes you're wearing can affect your performance.
  • Nervousness: Being pulled over is a stressful situation and can hinder your ability to process information accurately. Because of your mental state, you might mishear the instructions, or you may forget to do something like make sure your heel touches your toe.

Because the result of a field sobriety test can be affected by things other than alcohol, if an officer asks you to participate in them, politely refuse. Then, speak with a DUI lawyer as soon as possible.

At The Law Office of Thomas C. Thomasian, Esq., we have handled numerous DUI matters in Rhode Island and know that several defenses can be raised to challenge the accusations. Call us at (401) 312-4385 or contact us online today.