St. Louis DWI Lawyer – Field Sobriety Tests


Field Sobriety Tests are an important part of any DWI investigation and it is essential that the police officer administer these testsproperly.  There are three Standardized Field Sobriety Tests: the Horizontal Gaze Nystagmus Test, the Walk and Turn Test, and the One Leg Stand Test.  These three tests are considered Standardized Tests because each of them has a specific set of instructions and other criteria that the police officer must use when administering the test.  Each of the Standardized Tests also has a set of clues that the police officer should be looking for when administering the test.

Horizontal Gaze Nystagmus


During the administration of this test the police officer will examine a person’s eyes to see if the eyes twitch while performing different tasks.  The involuntary twitching of the eyeball is known as nystagmus.  There is a pretest to determine if a person is even a candidate for the Horizontal Gaze Nystagmus Test and then the actual test consists of the police officer looking for three different clues in each eye for a total of six clues.  The police officer looks for nystagmus during smooth pursuit of the eyes, then the officer looks for nystagmus when the eyes are at maximum deviation, and finally the officer looks to see if nystagmus begins prior to the eyes reaching 45 degrees.  If the police officer observes four or more clues during this test it is considered an indication that the person is intoxicated.

Walk and Turn

This test should consist of a person taking nine steps down a straight line, turning around, and then taking nine steps back down the same straight line.  Often, the line used in this case will be an imaginary because there is either no straight line available or the police officer did not utilize one if it was available.  During this test there are very specific things the police officer is looking for such as: did the person raise his arms; did the person take the correct number of steps; was the turn performed exactly as directed; and did the person step off the line during the test.  The police officer will also be looking to see if the person started the test before he was instructed to begin and if he was able to maintain the starting position while the officer gave the instructions for the test.  In total there are eight specific clues the police officer is looking for and if two or more clues are observed then it is considered an indication that the person is intoxicated.

One Leg Stand

This test is exactly what it sounds like, the police officer has the person stand on one leg for thirty seconds while having the person count out loud.  There are only four clues the police officer looks for on this test: putting the foot down; hopping; swaying; and if the person raised his arms for balance.  If the police officer observes two or more clues then it is considered an indication that the person is intoxicated.  In practice it seems that if one of the three Standardized Field Sobriety Tests is passed then it is usually the One Leg Stand Test.

There are also a number of field sobriety tests that are not standardized which means the tests have no set administration or specific clues that the police officer is looking to observe.  Examples of field sobriety tests that are not standardized are: counting, counting backwards, alphabet, finger-to-nose, and rhomberg.  The courts view these field sobriety tests similar to ordinary observations made by the police officer such as if a person had slurred speech or swayed while he walked.

If you or a loved one has been charged with DWI please call The Law Office of Jason A. Korner at (314) 409-2659 today.  It is important to have your case reviewed by a knowledgeable lawyer who focuses on aggressive DWI defense.  Jason Korner has been certified in the Administration of Field Sobriety Tests which allows him effectively challenge a police officer’s knowledge and administration of these tests.

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