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DUI "Field Sobriety Tests"-What Are They?

Posted Wednesday, March 1, 2017 by Andrew Charles Huff

Unlike blood alcohol content (BAC) or other DUI tests, field sobriety tests are voluntary in Washington and most other states. In many cases, you can decline to take one. The key is in determining whether or not the field sobriety tests as administered are valid evidence. These tests are usually used when a person is stopped on the suspicion of drinking and driving.

The most common Field Sobriety Tests (FST’s) are:

  1. One-Leg-Stand Test

  2. Horizontal Gaze Nystagmus (HGN) Test

  3. Walk and Turn (WAT) Test

History of Field Sobriety Tests

The National Highway Transportation Safety Administration created a standardized model for field sobriety testing in 1981. The Standardized Field Sobriety Test (SFST) uses three tests in combination, and the NHTSA recommends that all law enforcement agencies use this standardized program and the associated training.This standardized testing system - a system that NHTSA has deemed the most reliable of the available field tests - can be a DUI defense in an area where the standardized tests aren’t used.

Even where the standardized test is used, there may be some errors in the test. The SFST was designed to help officers measure the appropriateness of making a DUI arrest, not necessarily as evidence to prove that a driver was intoxicated. According to 1998 data from the NHTSA, the combination of three tests used together was only accurate in 91% of DUI cases. The arresting officer is wrong in 9 out of every 100 field sobriety tests - and those were the rates for the officers who volunteered DUI arrest records.

Not all officers who use the SFST as a preliminary DUI assessment have been properly trained to administer and interpret the test. Accurate administration of the three tests according to NHTSA procedures requires that an officer follow strict guidelines. All three tests must be administered under certain conditions.

Field sobriety tests can become a critical piece of evidence in a DUI case when a BAC or breath test was refused or the test has been found to be unreliable and suppressed.Some DUI courts may admit field sobriety tests that were administered imperfectly and let the DUI attorney argue the inaccuracy. Other DUI courts have ruled tests not administered

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