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Field Sobriety Tests

The Standardized Field Sobriety Tests (SFST) were developed by the National Highway Traffic Safety Administration (NHTSA). NHTSA claims that these tests provide reliable indicators of intoxication. These tests are categorized as “divided attention tests”. They are designed to see if a person can follow instructions, while at the same time being made to perform physical tasks. These tests are often administered in less than ideal conditions.

Because these tests are “standardized”, failure of a law enforcement to implement them in the prescribed standardized manner, compromises the validity of the results.

The SFST battery includes 3 divided attention tests, horizontal gaze nystagmus (HGN), walk and turn (WAT), and one leg stand (OLS) tests

1) Horizontal Gaze Nystagmus (HGN)
The HGN test requires a person to follow a stimulus, usually a pen or finger, with their eyes only. As the officer moves the stimulus from the center to the periphy of the person’s vision, the officer is looking for “lack of smooth pursuit”, and for an involuntary “jerking” or “twitching” of the person’s eyes, which is known as nystagmus. While alcohol consumption can in fact cause nystagmus, it can also be caused by over 80 other conditions unrelated to the consumption of alcohol.

Be aware that if a person moves their head during testing, that officers are trained to document this as evidence of impairment.

Evidence of HGN is not admissible for any purpose in Kansas Courts. The Kansas Supreme Court recently compared this test to a Ouija board or majic 8 ball, and dismissed it as “voodoo”.

2) Walk and Turn (WAT)
The Walk and Turn test commences with the officer placing the subject in the unnatural and uncomfortable position of standing on a line, right foot in front of left, touching heel to toe. The subject is required to stand in this position while the officer explains and demonstrates the rest of the test. If the subject steps out of this position, for whatever reason, that is one clue, two clues is considered failing. The remainder of the test consists of the subject walking 9 heel to toe steps down the line, performing a turn as instructed, and returning 9 heel to toe steps back up the line. During the test the officer is looking for clues such as using arms for balance, stopping while walking, stepping off the line, or missing heel to toe. The officer will not inform the subject how the test is scored, and generally will not give second chances because the NHTSA manual states “This test may lose its sensitivity if it is repeated several times”, i.e. if people figure out the game, it won’t work any more.

This test is designed for failure. If you are asked to perform this test, you should politely decline.

3) One Leg Stand (OLS)
The one leg stand test requires the subject to stand on one foot, and raise their other foot approximately 6 inches off the ground while pointing their toe. The person is required to stay in that position, and count by 1 thousands, until the officer tells them stop, which is supposed to be at 30 seconds. During this time the officer observes the subject to see if they use their arms to balance, sway, put their foot down or hop. If the subject does any of those things, the officer will use them as clues of impairment. During this test, the officer will also demand that the person “look at their foot”. The purpose of this is to take away the horizon, which will affect the person’s balance. You never see a high wire walker looking down. Two clues is considered a failing score on this test.

This test is designed for failure. If you are asked to perform this test, you should politely decline.

During his investigation, the officer may ask a subject to perform other tasks such as counting backwards from an arbitrary number such as 63-45, or may ask the person to recite the alphabet, without singing, from C-O. These tasks are designed to take you out of your comfort zone in hopes that you will make some sort of mistake that they can point to as evidence of intoxication

Another test officer’s sometimes request is the Rhomberg Balance Test. During this test, the subject is required to stand with their feet together, close their eyes, tilt their head backwards and attempt to touch their nose with the tip of their finger. The subject is then asked to estimate 30 seconds. The officer will use any deviation as evidence of impairment. Interestingly this test is designed to test for brain injuries, but according to Law Enforcement it can detect impairment.

If an officer requests that you perform any of these tasks, you should politely decline.