The Standardized Field Sobriety Test (SFST) is a battery of three tests administered in order to obtain validated indicators of impairment and establish probable cause for arrest.  The three tests of the SFST are: 1) Horizontal Gaze Nystagmus; 2) Walk and Turn; and, 3) the One Leg Stand.  These tests are administered and evaluated based on the measured responses of the suspect.

1) HGN Testing: is an involuntary jerking of the eye that occurs naturally as the eyes gaze to the side.  Normally, nystagmus occurs when the eyes are rotated at high peripheral angles.  When a person is impaired by alcohol, the rotation is exaggerated and may occur at lesser angles.  A person who is under the influence of alcohol will often have difficulty proficiently tracking an object.  In this test, the examiner looks for three indicators of impairment in each eye: if the eye cannot follow the moving object smoothly, if jerking is distinct when the eye is at maximum divergence, and if the angle of onset of jerking is within 45 degrees of center.  The officer will discern whether the suspect is over 0.08 BAC if, between the two eyes, a certain number of clues appear.

2) Walk and Turn: This test is very easily performed by most unimpaired people.  This test requires a suspect to listen to and follow instructions while performing simple physical movements.  The suspect is required to take nine steps, heel-to-toe, along a straight line. After taking the steps, the suspect must turn on one foot and return in the same manner in the opposite direction.  There are eight indicators the examiner will look for in order to determine impairment.  These are: if the suspect cannot keep balance while listening to instructions, begins before instructions are finished, stops while walking to regain balance, makes an improper turn, or takes an incorrect number of steps.  Two or more indicators typically indicate a higher than 0.08 BAC.

3) One Leg Stand:  In the One-Leg Stand test, the suspect is instructed to stand with one foot approximately six inches off the ground and count aloud by thousand (one one-thousand, two one-thousand etc.) until told to place the foot back down.  The officer typically times the person for 30 seconds.  The examiner will look for indicators including swaying while balancing, using arms for balance, hopping to maintain balance, and putting the foot down.  Two or more indicators indicate more than a 0.08 BAC.

It is important that when a police officer administers these tests, they are doing so appropriately, and within the confines of the fourth amendment of the US Constitution.  If you or someone close to you has been given a Standardized Field Sobriety Test, it is important that the officer took multiple factors into consideration.  If you have any questions regarding the administration of “SFST’s,” please call the Law Offices of Reeves, Aiken & Hightower at 803.548.4444 or Toll Free at 877.374.5999.