Standardized Field Sobriety Tests

Standardized Field Sobriety Tests



What follows is a very cursory overview of Standardized Field Sobriety Tests (SFSTs). Paul Reynolds is one of the few DWI attorneys in Arkansas and across the nation who has been certified to administer the National Highway Traffic Safety Administration Field Sobriety Tests.




Field sobriety tests have been around as long as the enforcement of DWI/DUI laws. For years, field sobriety tests varied among officers within the same law enforcement agency as well as from one agency to another. Field sobriety tests were limited only by the officers' collective imaginations. In the late 1970's the DOT/National Highway Traffic Safety Administration (NHTSA), funded research to evaluate currently used physical coordination tests which were used to determine the relationship between intoxication and driving impairment, to develop more sensitive tests which would provide a reliable means of identifying persons with a blood alcohol level above the legal limit, and to standardize the tests. The researchers finally concluded that the three test battery, consisting of the Horizontal Gaze Nystagmus, Walk-and-Turn, and One-Leg Stand, offered a reliable field sobriety testing procedure. Additional research was to complete the development and validation of the test battery and to assess the battery's feasibility in the field, as well as its effectiveness for estimating the blood alcohol content of subjects and the identification of persons with a blood alcohol content above the legal limit.

Types of Field Sobriety Tests


Horizontal Gaze Nystagmus - Nystagmus is the involuntary jerking of the eye. It can be an indication of intoxication. However, the occurrence of nystagmus is not dependent upon the presence of an intoxicant in the body. Substances that would not interfere with driving ability can produce nystagmus, and nystagmus may be congenital or caused by structural neurologic disease.

Examples of possible manifestations of alcohol impairment emerging during nystagmus test include the inability to keep the head still; noticeable swaying, and the utterance of incriminating statements. Points are not deducted, however, for any of these behaviors.



Examples of conditions that may interfere with suspect's performance of the nystagmus test include a suspect having an artificial eye; having damaged or very weak vision in one eye; eye irritants such as wind, dust, and rain; and visual and other distractions which impede the test, such as traffic, blinking lights, rain, etc. Some persons who are not under the influence may exhibit nystagmus.


Nystagmus may also be caused by certain pathological disorders such as brain tumors, brain damage and some diseases of the inner ear.

Walk and Turn - In this test, the subject assumes a heel-to-toe stance with the subject's arms down at his side. The subject is to maintain this position until the officer tells him to begin walking. At that time, pursuant to the instructions given by the officer during the instruction phase, the subject is to take 9 heel-to-toe steps down a real or imaginary line, turn around and take 9 heel-to-toe steps back up the line. The turn is not a pivot, but instead is made by taking a series of small steps with one foot, keeping the front foot on the line. While walking, the subject is to keep his arms at his side, watch his feet at all times, and count his steps out loud.


One Leg Stand - The instructions for this test are given to the subject while the subject stands with his feet together, and arms down at his side until told to start. The instructions which are supposed to be given to the subject (with accompanying demonstration) are for the subject to stand on one leg (either leg), holding out the other foot approximately 6 inches off the ground, foot pointed forward so the raised foot is approximately parallel to the ground for a period of thirty seconds.. The subject is required to count out loud during the thirty second period.


Non-Standardized Field Sobriety Tests


There are other, non-standardized, field sobriety tests which have been approved for use by such organizations as International Association of Chiefs of Police ("I.A.C.P.") in their "Improved Sobriety Testing for Boating/Alcohol Enforcement" Student Manual and the U.S. National Park Service. These tests include, but are not limited to, the finger to nose test, the finger count test, the hand pat test, the alphabet test, the reverse counting test, and the coin pickup test.


The information detailed above has been summarized from the U.S. Department of Transportation, National Highway Traffic Safety Administration, DWI Detection and Standardized Field Sobriety Testing, Student Manual (2006).

© 2009 Paul D. Reynolds

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