In Texas, there is no legal requirement that you cooperate with field sobriety tests. A police officer has the right to ask for your participation, and any evidence gained through these tests is admissible in court. However, no one can force you to take part.
There is little reason to perform the tests. Their purpose is to help the police develop probable cause to believe that you are driving drunk. Failing the tests will get you arrested and hauled down to the station. However, there is no obvious way to pass the tests, and doing so will not exonerate you.
Only three standardized field sobriety tests are endorsed by NHTSA
According to a study cited by the National Highway Traffic Safety Administration, the three components of the standardized field sobriety tests are, when taken as a whole, only about 91% accurate in indicating alcohol impairment.
That said, there are reasons people fail these tests besides being drunk. Certain medical conditions, medications and disabilities can make it difficult to perform the tests. Failing a field sobriety test does not necessarily mean you’re drunk.
Here are the three tests that have a reasonable amount of science behind them:
Horizontal gaze nystagmus test: The point of this test is to observe whether your eyes jerk in a characteristic way. This jerking (called nystagmus) is thought to be exaggerated when a person is intoxicated by alcohol. The officer asks the driver to follow an object with their eyes. The officer is looking for jerking motions at various points in the process.
Walk and turn test: Here, the goal is to divide your attention. People who aren’t intoxicated often find it simple to walk, heel-to-toe, turn around and go back. People who are drunk may be unable to smoothly perform the walk and turn.
One-leg stand test: Can you lift one foot for about 30 seconds without losing your balance? According to this test, swaying, putting your foot down, hopping or putting your arms out for balance are evidence of alcohol intoxication.
Although these are the only three tests endorsed by NHTSA, officers often use non-standardized tests, as well. Some of these include:
- Counting the number of fingers raised by the officer
- Closing the eyes and trying to touch your nose with your finger
- Reciting the alphabet or counting backwards
- Standing with the feet together and tipping the head backwards
Ultimately, it’s not in your legal interest to participate in field sobriety tests.