Are field sobriety tests required by law?

Not in Tennessee. Field sobriety tests are a way for the police to develop probable cause that you are driving while intoxicated. They are aimed at identifying problems with balance, attention and physical abilities that may be impaired by alcohol or drugs.

The police may ask you to perform these tests, but you cannot be forced to do so. In fact, some criminal defense attorneys recommend refusing to perform such tests.

What are the standard field sobriety tests?

There are three standardized field sobriety tests that are endorsed by the National Highway Traffic Safety Administration:

Horizontal gaze nystagmus test: When you turn your gaze to the side, your eye may involuntarily jerk. This jerking is called “nystagmus.” When someone has been drinking, the jerking is often exaggerated. So, when a police officer asks you to follow an object with your eyes, they are looking for distinct eye jerking at specific spots. This test is not admissible in Tennessee, yet officers will still often perform this test when stopping someone for a DUI.

Walk and turn test: The purpose of this test is to divide your attention so that it is more difficult to perform a relatively simple test. The belief is that most people who aren’t impaired can walk heel-to-toe in a straight line, turn on one foot and repeat the process in the opposite direction, but that people who are impaired by alcohol will have trouble. However, there are a variety of reasons other than impairment that may cause someone not to perform well on this test.

One-leg stand test: Here, the goal is to test your balance. The driver is asked to lift one foot about six inches off the ground and then count for 30 seconds. The belief is that an impaired person is likely to hop, sway, use their arms for balance or put the foot down. However, there are medical and physical reasons why this test may be difficult for someone who is not impaired.

There are also a variety of non-standard tests that officers may use, including:

  • Standing with your feet together and head tipped backwards
  • Counting the number of fingers raised by an officer
  • Reciting the alphabet
  • Counting backwards
  • Standing and leaning back to look at the sky while holding the arms to the side
  • Closing the eyes and attempting to touch your nose with your finger

What is the downside of refusing field sobriety tests?

The tests are generally used to develop probable cause against you. If you fail, the officer can haul you down to the station for an official blood or breath test. However, the officer may have an unofficial, hand-held breath testing machine that can also develop probable cause to believe you are intoxicated.

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