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Did you “fail” the Horizontal Gaze Nystagmus (HGN) Test?

by | Sep 13, 2015 | 0 comments

Horizontal Gaze Nystagmus (HGN) Test in Georgia

When you are suspected of DUI in Georgia, you will be asked by the police officer to undergo several tests, more commonly known as Field Sobriety Tests (FBTs). Officers are allowed to administer three tests in the field: (1) the Walk-and-Turn; (2) the One-Leg Stand; and (3) The Horizontal Gaze Nystagmus (HGN) test. Of the three, the HGN test is the most contested throughout the nation and in Georgia.

What is the Horizontal Gaze Nystagmus (HGN) Test?

The HGN test is based upon the degree of onset of nystagmus, or jerking, of a person's eyes as he follows an object visually without moving or turning his head. Typically, the officer holds a pen and flashlight before your eyes and has you follow it back and forth.

Police officers routinely administer the HGN test to determine whether or not a driver has been drinking. At trial, prosecutors will try to use the test as concrete evidence of drunk driving. They usually argue that of the three field sobriety tests, the HGN is the most closely tied to actual Blood Alcohol Concentration (BAC) level and is thus more indicative of how much alcohol a person has consumed. The theory is that a person with a high BAC will not be able to control their eye movement and the will "fail" the test.

However, such an argument is misleading. The results of an HGN test are not concrete evidence of drunk driving. Many scientific studies of the HGN test have shown that its reliability has been greatly exaggerated and that a form of nystagmus continues to be visible in many subjects for one to six hours after all alcohol leaves the bloodstream! This means that you can have a very low BAC (and be well within the legal limit to drive) and still fail the test. This is why many researchers have now deemed the HGN to be junk science.

Failing the HGN may not matter

Still, many people don't fight their DUI charges because they believe that since they failed their field sobriety tests, they don't have a good case. What they don't understand is that performance on the HGN field sobriety test is not concrete evidence of drunk driving!  If you've been charged with DUI on the basis of a bad performance on any field sobriety tests, call and consult with me about your case and all the options available to you.