Field Sobriety Tests Are Not Always Accurate

Law enforcement relies on a variety of field and lab sobriety testing to determine if a suspected drunk driver is over the limit. While generally regarded as accurate, there is a chance that your test results may not hold up in court due to possible errors in test administration. 

Experienced OWI/DUI defense attorneys know that field sobriety tests can produce misleading results. Your lawyer will thoroughly investigate the testing circumstances to ensure that your OWI charges are judged fairly. 

Field Sobriety Tests Are Gatekeepers to Further Testing

Some sobriety tests, like breathalyzers and blood tests, reveal your Blood Alcohol Content (BAC) at the time the test is administered. Police may also use subjective measures like the horizontal gaze nystagmus (HGN) test, the walk-and-turn test, and the one-leg stand test to approximate sobriety when you are pulled over.

None of these tests are foolproof, however, and it is important for the court to assess their accuracy before relying on them to convict.

If you are pulled over for suspected drunk driving, the officer may ask you to submit to side-of-the-road field sobriety testing. These subjective tests often act as a gatekeeper to further sobriety testing. If the officer determines that you failed any of these tests, they may have probable cause to ask you to come back to the station and submit to further blood, urine, or breath testing. 

No Field Sobriety Test Is Foolproof

There are three types of field sobriety tests that law enforcement may ask you to perform on the side of the road in Wisconsin. 

  1. The Horizontal Gaze Nystagmus (HGN) test requires the officer to move their finger or another small object across your field of vision as you follow it with your eyes. Repeated inconsistent, jerky eye movements could indicate intoxication to the officer.

    This test, like other field sobriety tests, is judged entirely at the officer’s discretion. There is a lot of room for error. Following a small object at close range can be a challenge even if you are sober. Taking the HGN test on the side of a busy street could lead to eye-catching distractions that impact the results. In addition, officers are often inconsiderate of health conditions that can cause the same kinds of jerky eye movements that could flag you for intoxicated driving.
  2. Performing the one-leg stand test involves standing on one foot for an extended period of time. The officer will then assess your balance, looking for clues such as hopping and flailing your arms to determine sobriety.

    Inherent balance and physical ability can contribute to errors in the one-leg stand test. Balancing on one foot can be challenging even if you are 100% sober. When your OWI attorney visits the test site, they could also determine that uneven pavement contributed to inaccurate test results.
  3. The nine-step walk and turn test will require you to take nine heel-to-toe steps in a straight line, turn, and walk back in the same fashion.

    Similar to the one-leg stand test, physical ability and testing environment can lead to inaccurate results. The officer is trained to look for clues such as trouble balancing or difficulty placing one foot directly in front of the other, but uneven terrain and your baseline physical ability may call positive results into question.

The judge needs to consider all the facts before they make an OWI/DUI conviction. If a conviction hinges on field sobriety testing, a knowledgeable drunk driving attorney may be able to demonstrate critical errors in test administration and get your charges reduced or dismissed.