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DWI Defense

Field Sobriety Tests

One of the tools Texas law enforcement officials use in the course of any given DWI investigation is a field sobriety test. It is well known across the country and state that these tests exist, but the specifics of the tests used and their history are not nearly as well known.

Prior to the 1970s there were dozens of sobriety tests used in different ways by different police departments nation-wide. In 1975 the National Highway Traffic Safety Administration set out to normalize and set standards for a battery of tests that all police departments could use to detect whether a DWI suspect was impaired by alcohol. What resulted from those efforts was the development of a battery of three field sobriety tests that are now used in Texas and nearly every other state by police officers in DWI investigations.

Three Popular Test Used by Texas Law Enforcement

  • Horizontal Gaze Nystagmus Test: The Horizontal Gaze Nystagmus Test is possibly the most widely used and accepted test in the country. To conduct this test a police officer will ask a driver to follow the officer’s finger from side to side with the suspect’s eyes. The theory behind the test is that if a person is impaired by alcohol the person’s eye will involuntarily jerk in an exaggerated way during the test. If the suspect’s eye does this, an officer will likely conclude that the person is impaired and then arrest that person on suspicion of DWI. There are a number of problems with this test, however. Using an involuntary jerking of the eye as the basis for concluding that someone is impaired can be flawed because a person’s eye may jerk in that way for numerous reasons. Medications can cause this to happen, sleepiness, and nerves as a result of being tested by police can also cause it to happen.
  • One-Leg Stand Test: Just like it sounds, an officer conducts this test by asking a DWI suspect to stand on one leg while the officer asks the person certain questions. Based on how the DWI suspect reacts to standing on one leg and to the questions, the officer then makes a determination about whether the person is impaired. The problems with this test are quite obvious. In the first place it is not an easy thing for everybody to stand on one leg while paying attention to what a police officer has to say. Old age, physical impairments, and other factors besides drinking alcohol affect this test every time it is administered.
  • Walk and Turn Test: The walk and turn test is also just as it sounds. The police officer asks a DWI suspect to take ten steps, turn around, and walk back. Based on how the suspect takes the steps and listens to the officer, the officer will determine whether to arrest the suspect on DWI charges. Of course this test suffers the same limitations as the one-leg stand test.

Protecting Your Rights

Each field sobriety test is subjective and the results are based more on a police officer’s opinion and motivations than on the actual facts in a case. That is why every person pulled over by the police and asked to take a test should think seriously about whether to take the tests or not. A police officer may have already made a determination about whether an arrest will be made, and the tests may just be a way to add more evidence to their case. If you have been arrested on DWI charges in the Dallas area, contact us. At the Wilder DWI Defense Firm we will go over your case with you and provide you with your legal options.