How to Successfully Dispute the Results of a Field Sobriety Test

So the National Highway Traffic and Safety Administration has established three standardized field sobriety tests that officers can administer if they believe they have found someone committing a DUI.


Horizontal Gaze Nystagmus (HGN) Test

What is it?

The HGN test is when an officer tells you to focus on a pen or a finger about one foot from the driver’s face, and then moves the object from side to side. Though a nystagmus is an involuntary twitch that typically occurs when a person looks sideways at an angle greater than 45 degrees, research has found drugs and alcohol can depress the central nervous system, hindering the brain’s ability to properly control the eye muscles at angles less than 45 degrees. The more intoxicants that a person consumes, the more obvious these nystagmi become.

What do police look for?

While conducting the HGN test, officers are looking for six different ‘clues’ that the driver is intoxicated. If a subject exhibits four or more of these ‘clues’ then the officer will most likely conduct further field sobriety tests: 1. Lack of smooth pursuit in left eye 2. Lack of smooth pursuit in right eye 3. Distinct and sustained nystagmus at maximum deviation in left eye 4. Distinct and sustained nystagmus at maximum deviation in right eye 5. Onset of nystagmus prior to 45 degrees in left eye 6. Onset of nystagmus prior to 45 degrees in right eye.

How do I beat the HGN?

The short answer is, get a lawyer. Nystagmi are involuntary responses, meaning that it’s near impossible to prevent yourself from failing the test in the field. With a 77% accuracy rating in detecting blood alcohol content levels of .10% or higher, the HGN has also proven to be the most accurate indicator of the three standardized field sobriety tests. That being said, law enforcement officials are notorious for administering the test incorrectly, leaving the alleged DUI recipient some grounds to argue their innocence. For instance, if the field sobriety test was administered at night (assumingly with cars driving past on both sides of the road), one could argue that it was distractions that caused the nystagmus and not alcohol. Further, there are several different causes for nystagmus beyond intoxication, and a defense attorney may argue that the nystagmus was caused by anything from contact lenses to ear infections to eye muscle fatigue from long hours of driving.


Walk And Turn Test

What is it?

The walk-and-turn test is exactly how it sounds. An officer will ask you to walk nine steps heel-to-toe, pivot to turn around, and then walk back in a similar fashion.

What do police look for?

Police look for several different cues during the walk and turn test to determine whether someone is intoxicated. If the officer observes two or more of any of the following, then it can be argued in court that they had probable cause that the subject has a BAC above .10%: 1. Inability to stay balanced while receiving instructions 2. Starting or stopping the test before indicated 3. Failure to touch heel-to-toe 4. Stepping off of the line 5. Excessively using arms to balance 6. Improperly turning 7. Using the incorrect number of steps

How do I beat the walk and turn test?

Due to its low accuracy (about 68% accurate in identifying blood alcohol content levels of .10% and above) there are a few ways to fight the walk and turn test in court. Firstly, elderly, overweight, or people with back, leg, or inner ear problems often have difficulty passing this test when sober. Second, the test must be administered on dry, hard, level land so that external conditions do not play a role in the results of the test. A good lawyer should be able to guide you through the best coure of action as far as arguing the case.


One-leg Stand

What is it?

Similar to the walk-and-turn, the one-leg stand is exactly as you would picture. An officer will ask you to stand with your hands at your side and to raise either leg roughly six inches above the ground. The officer will then ask you to count upwards starting from 1,000 (i.e. one thousand and one, one thousand and two, etc.).

What do police look for?

Officers look for four different signs that indicate a person may be intoxicated during the one-leg stand test: 1.Swaying while balancing – though this is natural for all humans to do, officers are trained to look for marked swaying or exaggerated movements. 2. Using the arms to keep balance – if the subject raises his or her arms more than six inches from the side of the body, then it shows that they are having a hard time maintaining balance. 3. Hopping on the anchor foot in order to maintain balance – it is permissible for a person to move the anchor back and forth slightly, but raising it off the ground is not allowed. 4. Resting the raised foot on the ground three or more times during the required thirty seconds – this person is considered unable to complete the test.

How do I beat the One-leg stand test?

Exactly the same as the walk and turn test.


If you found this article helpful consider reading:

What To Do At A DUI Checkpoint 

Critical Mistakes Made In The DUI Process

Do I Need An Attorney For My DUI?

Tips to Win Your DUI Case

Updated: October 18th, 2016

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Revised: Feb. 11, 2016, 8:02 p.m.
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