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Standardized Field Sobriety Tests: What Are Police Looking For?

If you have ever seen a movie or television show depicting drunk drivers, you may have seen police officers asking drivers to say the alphabet backwards, count fingers or touch their noses in order to help determine whether the driver is intoxicated. In reality, law enforcement officers will very rarely use those often-depicted tests because more reliable tests exist.


The three most common Standardized Field Sobriety Tests (SFST) that a police officer will likely ask you to perform if he or she suspects you of driving while impaired are: One Leg Stand, Walk and Turn, and Horizontal Gaze Nystagmus.


One Leg Stand

Officers will likely ask you to stand with one leg out in front of you – parallel to the ground—approximately six inches off the ground for nearly thirty seconds. While officers are giving you instructions for the test, you will be instructed to stand with your feet together, keep your arms at your side and listen to performance instructions.


During the performance part of the test, officers are looking to see if you exhibit any of the following four clues:

·      Swaying

·      Using your arms for balance

·      Hopping

·      Dropping your foot


Walk and Turn

Officers will also likely ask you to take nine heel-to-toe steps in a straight line, turn 180 degrees on one foot and repeat the steps in the opposite direction following either an actual or imaginary line. During this exercise, officers want you to watch your feet, count out loud and keep your hands at your side.


During the performance part of this test, officers are looking to see if you exhibit any of the following eight clues:

·      Starting the test too soon

·      Using hands for balance during the test

·      Not maintaining balance during instructions

·      Stepping off the line

·      Missing heel-to-toe by more than ½ inch

·      Incorrect turn

·      Wrong number of steps

·      Stopping the test early


Horizontal Gaze Nystagmus

Nystagmus is the involuntary jerking of the eyes that can be caused for a number of reasons, including alcohol impairment. Horizontal Gaze Nystagmus (HGN) is an involuntary jerking of the eye that occurs naturally as the eyes are rotated at high peripheral angles. Alcohol and certain other drugs can cause exaggerated HGN and trigger HGN at an angle of less than 45 degrees. Before the test an officer will check the subject for equal pupil size, resting nystagmus and equal tracking to rule out any medical condition that may render the test ineffective. An officer will then ask you to follow a stimulus that he or she will move from left to right and right to left while watching for certain clues. A common misconception is that officers look for you to follow the stimulus without head movement. Although officers will note that, it is not a clue they are specifically looking for.


While performing the test an officer will be looking for the following clues in each eye:

·      Lack of smooth pursuit (i.e. – jerking while following an object)

·      Nystagmus at maximum deviation

·      Nystagmus prior to 45 degrees


Each of these tests has defenses that you may want to explore with your DWI/DUI attorney. The attorneys at The Law Offices of Wiley Nickel have experience challenging the results of these tests, along with all other aspects of your DWI/DUI case. Contact our office at 919-585-1486 to speak with one of our experienced attorneys today about your options.

Wiley Nickel