Field Sobriety Tests and DUI Defense

If you are stopped by law enforcement while driving and the officers suspect you have been drinking, they may want to perform different kinds of tests to determine whether you are driving under the influence (DUI). In addition to Breathalyzer and blood tests, the results of which must be processed by a forensic lab, officers may perform a set of tests at the site of the traffic stop. These tests are known as Field Sobriety Tests (FSTs). In FSTs, the officers will ask you to perform a series of exercises that test your mental and physical capabilities, such as balance, coordination, and ability to follow instructions.

There are three standard FSTs approved by the National Highway Traffic Safety Administration (NHTSA). These tests are as follows:

  • Horizontal Gaze Nystagmus test—the officer asks you to use your eyes only to follow an object that he moves from left to right. The officer is actually watching your eyes for early “nystagmus,” a jerking of the eye, which is a sign of intoxication.
  • Walk and Turn test—the officer asks you to take nine steps in a straight line, pivot, and then take nine steps in a straight line back. Not only is the officer looking for balance issues, but also your ability to remember and follow his instructions.
  • One-leg Stand test—you will be asked to stand on one leg, count from 1001 to 1030, and then to look down at your foot. An officer is mainly looking for balance problems with this test.

Not only do police officers use their perceived results of FSTs in order to decide whether to arrest you, but these results may also be used against you if you are prosecuted for DUI. The arresting officer will almost definitely testify against you at a DUI hearing and recount his impressions of your performance on FSTs. For this reason, challenging the accuracy of the FSTs is an important part of DUI defense.

Questionable FST results

NHTSA studies show that the Nystagmus test has a 77% rate of detecting intoxication, the Walk and Turn test has a 68% success rate, while the One-leg Stand test is only accurate 65% of the time. This means that one-third to one-fourth of people who are found to be intoxicated by FSTs are actually not impaired. These accuracy results only decline further if the officer is not properly trained in FSTs or administers any of the tests incorrectly. An experienced defense attorney knows how to use the potential inaccuracies of FSTs to challenge DUI arrests and charges in order to avoid wrongful convictions.

Contact a Chicago Criminal Defense Lawyer for help

If you are facing charges for DUI or any other type of offense, an experienced and skilled defense attorney can identify any possible defenses in your case, and will make sure your rights are protected. Do not risk being wrongfully convicted based on inaccurate test results or other evidence. Instead, contact attorney Steven Goldman at Goldman & Associates for help as soon as possible.

Practice Areas

Our Blog