The Los Angeles DUI Law Blog

Fighting Field Sobriety Tests: 3 Potential Weak Points

After the Breathalyzer test, field sobriety tests (FSTs) may be the part of a DUI stop that most people remember. But FSTs can often be challenged in court.

Based on a driver's specific situation, the FST may have been performed incorrectly or may not be a reliable indicator that a driver is intoxicated.

Here are three common weak points in field sobriety tests that can potentially be challenged by a driver facing a DUI charge:

1. The FSTs Were Not Performed Correctly.

Officers often have a lot on their minds when pulling over a driver suspected of DUI, so they may not be following proper procedures.

The National Highway Traffic Safety Administration (NHTSA) sets specific guidelines for what they call a standard FST, which includes:

  • Horizontal gaze nystagmus (HGN), a test which tracks eye movement.
  • Walk and turn (WAT), which requires a driver to walk heel-to-toe.
  • One-Leg Stand (OLS), a balancing exercise for a set amount of time.

If any of these tests are performed outside of the boundaries set by the NHTSA, or if the officer performs a non-standard test (such as making a driver spell the alphabet backwards), the results of the FST can be challenged as unreliable.

2. Poor Conditions in the Testing Area.

When a driver is pulled over on suspicion of drunken driving, police often do not pick the most ideal place for walking and/or balancing.

Here are some common poor conditions that can cause even a sober driver to fail a field sobriety test:

  • Slippery or uneven surfaces. Pot holes, muddy ground, and chipped pavement can cause a driver with normal coordination to stumble, slip or fall.
  • Very little to no lighting. Unless the officer provided a flashlight or headlights to illuminate the ground, these tests can be near impossible to perform in the dark.
  • Hard to hear the officer. Highway noises or other ambient sounds may drown out an officer's instructions and make it difficult to follow the tests.

3. Medical Conditions Can Skew FSTs.

Certain medical conditions can cause a driver to have improper balance, such as an inner-ear infection, which may cause them to fail the standard FSTs even while sober. In other cases, neurological injury or even epilepsy can cause eye movements that may cause officers to falsely determine an individual is drunk.

If you are facing charges for driving under the influence and have questions about any of these issues, contact a Los Angeles DUI attorney today.

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