Updated: May 31
Phase Three consists of three standardized field sobriety tests or, SFSTs, that were developed by the National Highway Traffic Safety Administration (NHTSA) and that are in use by officers throughout the United States plus a preliminary breath test, or, PBT. They must be administered in a standardized way every time in order to retain what little scientific value they purport to import to OWI suspicion.
For example, the horizontal gaze nystagmus, or, HGN, must start with the left eye every time. And the scoring for each eye is to consider three phenomena that studies have correlated to intoxication, including lack of smooth pursuit, distinct nystagmus at an approximate 45 degree angle before the onset of maximum deviation, and distinct nystagmus at maximum deviation. In studies commissioned by the NHTSA, a decision point in the HGN is four so-called clues, or, signs of insobriety. Even then, the studies indicate the HGN is only 77% accurate. In other words, of those who showed four or more clues, 23% were not over the presumptive legal limit of .10 grams ethanol per 210 L breath at the time of their testing. You’ll note that the .10 limit has been reduced .08 BrAC/BAC in all 50 states. The research was conducted before the change. However, the NHTSA and law enforcement agencies who use this testing assert that they have “revalidated” the tests and that they are “accurate” to the reduced standard.
The HGN test is considered the gold standard and “the most reliable” of all of the SFSTs. The so-called “gold standard” provides only 77% reliability even by NHTSA's own admission.
The Walk and Turn, or, WAT, is typically the second SFST administered by an officer in the field. The Walk and Turn consists of an instruction/demonstration phase and the test phase. Some officers “con” test subjects into beginning the test early by refusing to tell the test subject that he or she must not begin until and unless instructed to do so. When a test subject attempts to follow along by mirroring the officer’s instructions and demonstrations, it’s considered a “clue,” or, sign of insobriety.
The test includes nine heel to toe steps, a turn consisting of a series of small steps, and a return set of nine steps, all while counting out loud, for example, “one-thousand-one,” and so forth.
In addition to the signs of insobriety cited in the instruction/demonstration phase, the officer looks for incorrect number of steps, stopping, and improper turn.
NHTSA has concluded that just two “clues,” or, signs of insobriety comprise a “decision point” on this test because those who showed two such signs during testing were shown to be over the presumptive legal limit of intoxication just 68% of the time.
If you or a loved one have been arrested for OWI (DUI) or other criminal offense in Cedar Rapids, Iowa City, or other Iowa community, contact us. However, remember that a blog is not legal advice and that sending information to a lawyer over the Internet does not establish an attorney-client relationship.