Don’t Hop During the One Leg Stand

Moriarty & Associates on the One Leg Stand Test for Drunk DrivingThe one leg stand (OLS) is the final test administered as part of the Standardized Field Sobriety tests (SFST) regimen. This test sounds quite simple, but that can be deceiving. The OLS is a divided attention test, and the National Highway Traffic Safety Administration (NHTSA) cites studies claiming that it’s only 65% accurate at detecting people with breath alcohol concentrations of .10 or above.

Similar to the Walk and Turn Test, the OLS consists of two phases: an instruction phase and a performance phase. During the instruction phase, the person is directed to stand with their feet together, keep their arms at their sides, and listen to instructions.

During the performance phase, the person must raise one foot, either foot, approximately six inches off the ground, with both legs straight and the raised foot parallel to the ground. While looking at the elevated foot, the person counts out loud: “one thousand one,” “one thousand two,” “one thousand three,” until told to stop. This divides the subject’s attention between balancing (standing on one foot) and counting out loud.

The officer times the person for 30 seconds. The Standardized Field Sobriety Test Manual (see all manuals here) states that the timing for a 30-second period by the officer is an important part of the One Leg Stand test because research showed that many impaired subjects are able to stand on one leg for up to 25 seconds, but that few can do so for 30 seconds.

During the test, the officer looks for a number of clues, including balance problems, stepping out of position, or the person moving his or her hands away from his or her side during the instructions phase. During the performance phase, the officer looks for four clues:

  1. The person sways while balancing;
  2. The person uses his or her arms to balance;
  3. The person hops; and/or
  4. The person puts his or her foot down.

Exhibiting two of four clues means that you failed the test. Remember, the officer does not tell the person what issues will be considered against them when they perform the test.

Horizontal Gaze Nystagmus, Walk and Turn, and One Leg Stand tests are effective tools for a prosecutor to obtain a conviction against a defendant. Although the officer offers these tests under the guise of determining whether a person is safe to drive, they are most effective at procuring evidence that the prosecutor can present at trial to obtain a conviction. It is for this exact reason that I recommend that people do not agree to perform field sobriety tests and assert your right to a lawyer at the earliest opportunity.

Attorney Patrick M. Moriarty earned his Juris Doctorate from Western New England College School of Law in 1990. He is the founder of Moriarty & Associates, PLLC, and serves as a judge pro tempore in district and municipal courts in Snohomish County. Learn more.

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