Field Sobriety Tests (FSTs)

Field Sobriety Tests (FSTs) Have Ample Room For Error

Field sobriety tests (FSTs) are conducted at traffic stops as part of determining probable cause for a driver's impairment. If you were stopped on suspicion of drunk driving, you were probably asked to step out of your vehicle to take one, two or all three of these tests. They are the horizontal gaze nystagmus (HGN), the walk-and-turn (WAT) and the one-leg stand (OLS).

Various medical and physiological conditions can exist that prevent a completely sober person from successfully completing these tests. There is ample room for error. The DUI defense attorneys at Ryan & Grinde, Ltd., have extensive knowledge of the FSTs, the methods for administering FSTs and the types of errors that can occur. To get started today on your defense, call us in Rochester at 507-218-7935 or toll free at 888-399-7281.

We Dispute The Accuracy Of FSTs

According to the National Highway Traffic Safety Administration (NHTSA), the HGN is 77 percent accurate, the WAT is 68 percent accurate and the OLS is 65 percent accurate. Often, law enforcement will use two tests — the HGN and the WAT — which results in 80 percent accuracy. There is still a 20 percent possibility of error.

  • Horizontal gaze nystagmus is used to check the driver's eye movements. The law enforcement officer takes a pen and holds it 12 to 15 inches in front of the individual's nose and moves it from side to side. Law enforcement then takes note of jerky eye movements. This test is performed by someone not in the medical field on the side of the road.
  • Walk-and-turn requires the driver to walk in a straight line for nine steps. The driver needs to walk heel-to-toe, turn around and return with nine heel-to-toe steps. The driver must keep his or her arms at the side of the body, keep their eyes on their feet and count all the steps out loud. This test looks for balance, steadiness and coordination. The room for error is significant, with everything from a driver wearing high heels to weather conditions being a factor.
  • One-leg stand requires the driver to stand on one leg with the other leg about six inches off the ground. Both arms are kept straight at the side of the body while the driver counts to 30. Law enforcement looks for swaying, moving arms, hopping and failing to maintain the position.

Any of the above FSTs can be difficult for a sober person to perform, even in the most ideal conditions. There are many factors that need to be analyzed, including the driver's medical and physiological history, attire, weather conditions, road conditions, the police officer's expertise in administering the tests and more.

Contact A Defense Attorney In Rochester For A Consultation

Ryan & Grinde, Ltd., can get to work immediately on your behalf. Call us at 507-218-7935 or toll free at 888-399-7281. You can also contact us online.