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What Are Texas Cops Looking For In Field Sobriety Tests?


Remember when you were in school and your teacher would “surprise” the class with pop quizzes? Field sobriety tests can be like that, except failing the test could mean some time in jail.

Make no mistake: you have a right to refuse Standardized Field Sobriety Tests (SFSTs) if a police officer stops you in Texas. Cops use SFSTs to determine if there is probable cause to arrest you, and these tests are used primarily to create or obtain evidence against drivers. Field sobriety tests are also subjective, meaning the officer’s perception of whether you’re sober or not factors largely in whether or not you’ll be arrested.

Cops routinely use these three Standardized Field Sobriety Tests.

A police officer might arrest you if you fail (or seem to fail) any one of these SFSTs:

  • Walk-and-turn (“WAT”): This test is all about balance and agility. An officer considering whether or not to arrest you for DUI may ask you to walk a straight line with your arms held out at shoulder length on each side. You can’t simply walk with a normal stride either, as you must walk with the heel of one foot at the tip of the toes on the other. Once you reach the end of the designated line, the officer may instruct you to turn around and repeat the whole exercise in the other direction. Really, this test can be tricky for anybody, sober or not.
  • One-leg stand (“OLS”): If you’re a clumsy type of person, standing on one leg may prove quite challenging, even when you’re sober. This field sobriety test may not be very reliable, but police officers still use it. While you’re standing on one leg, the officer will ask you to count out loud for 30 seconds and look straight ahead. If you sway, can’t count correctly, put your foot down, or hop around to catch your balance, your next road trip might be straight to jail.
  • Horizontal gaze nystagmus (“HGN”):This test measures your eyeball movements when a police officer asks you to follow an object using only your eyes, not your head. The officer may hold up a finger or a pen, then move the object from side to side or up and down, all the while checking to see if your eyeballs jerk sooner than expected on average for peripheral gaze. Intoxicated people’s eyes tend to move erratically before they’ve reached their maximum gaze points.

How Are The Roadside Tests Graded?

Texas cops score each of the three standardized field sobriety tests differently. Each test has certain “clues” that could indicate intoxication and if you demonstrate too many clues, then officers are trained to consider you intoxicated. For the WAT, only two clues are needed to fail, out of 8 possible clues. However, while you are being evaluated for 8 different types of errors, you have multiple opportunities to commit each error. For example, one clue is “steps off the line.” The line is, typically, an imaginary line pictured in the officer’s mind. You must take 18 steps on the imaginary line, meaning that if you, in the officer’s opinion, step off the imaginary line once out of 18 tries, then you have demonstrated a clue. Again, there are 7 other types of clues and you only need to show two to fail.

For the OLS, the point of failure is 2 out of 4 clues. The OLS requires you to successfully do four things for thirty seconds, meaning that you have a total of 120 chances to make an error. You need to complete the One Leg Stand about 99% correctly to pass.

The HGN test requires 4 out of 6 clues. Only the officer will be able to see the alleged clues unless he happens to have a camera focused directly on your eyes during the test. Even when the results can be verified, there are estimated to be 42 non-alcohol-related reasons your eyes might twitch in a manner the officer is trained to consider a clue. For example, medication, allergies, and genetics may cause the clues. In many instances, the officer may cause the clues by administering the test incorrectly.

Where To Turn For Support

The penalties for a DWI conviction are harsh in Texas, but you have a right to defend against the charge. You also don’t have to do that alone. Talk to an experienced DWI defense lawyer as soon as possible after a police officer pulls you over. The sooner a defense attorney can get involved in your case, the sooner steps can be taken to protect your rights and interests.