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The results of your standardized field sobriety test may be wrong

On Behalf of | Mar 30, 2023 | Criminal Defense

During a traffic stop, you may be asked to do a standardized field sobriety test (SFST).

These tests are often criticized for their inaccuracy. To understand why an SFST may be inaccurate, it’s important to know the different kinds of SFSs.

What are the different kinds of standardized field sobriety tests?

Standardized field sobriety tests were developed by the National Highway Traffic Safety Administration (NHTSA) to help law enforcement when evaluating the condition of a driver. There are three kinds of SFSTs:

  • Horizontal gaze nystagmus test (HGN): With this test, the police may ask you to use only your eyes to follow an object, such as a finger, light or pen. The police may be looking for any sudden eye movements or flickering. If your eyes are slow to react or catch the attention of other things, then it may be a sign of poor focus after drinking alcohol.
  • Walk-and-turn test (WAT): You may be asked to perform this test that involves walking in (or on) a straight line. After walking until you’re told to stop or after a said number of steps, you may be asked to walk back to where you started. The police may judge whether you lost your balance, had to stop multiple times or if you used your hands to keep your balance.
  • One-legged stand test (OLS): As the name implied, this test will have you standing on one leg, typically, for several seconds. If you lose your balance, start hoping to keep standing, put your foot down or fall, the police may believe you’re inebriated.

There is another category of tests called non-standard field sobriety tests (NSFST). An NSFST is any kind of test that isn’t listed above. For example, you may be asked to spin three times to see if you fall over or you may be asked to say the alphabet backward while keeping a finger on your nose – these tests can seem arbitrary.

Why would a standardized field sobriety test be inaccurate?

The problem is that standardized field sobriety tests lack scientific evidence. Law enforcement has to use their best judgment when using SFSTs to determine whether a driver is sober. For example, a driver who is able to hold their liquor may be well above the legal BAC limit, but they’re able to breeze past the tests. However, a driver with an eye disability may fail an HGN test despite being sober.

If you’re facing a DUI/OVI, understanding your legal options may help you create a strong defense against your case.