Field Sobriety Tests: Understanding the Three Forms — DWI Defense Louisiana

New Orleans DWI DUI Attorney 



Elizabeth B. Carpenter, Esq. —  DWI DUI Attorney New Orleans 


Field Sobriety Tests: Understanding the Three Forms

 By Elizabeth B Carpenter

In most Louisiana DWI cases, before breath and blood tests are utilized, law enforcement officers will use what is known as the field sobriety test. These are a common first way of determining the level of intoxication of the subject. For a long time, these tests were not standardized and were different across the board – varying from place to place. The National Highway Traffic Safety Administration (NHTSA), however, has since standardized this form of testing and has come up with three different tests:


Horizontal Gaze Nystagmus (HGN): This is the most scientific of all field sobriety tests and is used to test the nystagmus of the subject – which is the involuntary jerking of the eye. It is believed that the drinking of alcohol can exaggerate and aggravate nystagmus. To perform this test, an officer will take a small object (such as a pen or flashlight) and will place it before their eyes – moving it horizontally in front of them. They will then watch the eye’s tracking and will look for any distinct movement.

Walk-and-Turn (WAT): This is considered to be a “divided attention” test that requires the subject to listen to detailed instructions and then perform as asked. The WAT requires the subject specifically to walk in a straight line (heel to toe) for nine steps, turn on one foot and then return back to the starting point of the test. The officer will look for signs of failure which include using the arms to balance, steps off of the line, doesn’t take the specified nine steps or stops during the test.

One-Leg Stand (OLS): The simplest form of testing is known as the OLS and is another form of a divided attention test. This requires the subject to stand on one leg while raising the other for six inches off the ground – counting until the officer tells them that they are able to put their foot down. Signs of failure including using arms to balance, swaying, hopping to maintain balance or putting their foot down before the test is over.




When you are dealing with criminal charges pertaining to drunk driving, you need an aggressive attorney that you can rely upon.  Contact DWI DUI Attorney Elizabeth B. Carpenter — Available 24/7 to help you.



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