Fisher Law Office

Challenging horizontal gaze nystagmus test results

You just never know when a California police officer is going to flash lights or blare a siren in an attempt to pull you over in a traffic stop. Of course, if you were traveling at speeds in great excess of posted limits, such as going 50 miles per hour in a 25 mile per hour zone, chances are high that any police officer nearby who witnesses your high-speed travel will likely pull you over.

However, if you are doing your best to adhere to all traffic regulations, it doesn't necessarily guarantee that you will not run into trouble. For instance, if a police officer traveling behind you claims that your tires veered over the yellow line, he or she can make a traffic stop on suspicion of drunk driving. What happens after that depends on various factors, one of which may be whether or not you pass a horizontal gaze nystagmus test. Failing this test may prompt an immediate search for legal help.

Know the facts and where to turn for support

The horizontal gaze nystagmus test is one of several common field sobriety tests police officers may request you to take if they think you have been driving under the influence of alcohol. The following list includes facts about how the HGN test works and why DUI defendants often challenge HGN results in court:

  • The term, "horizontal gaze nystagmus" refers to an eye movement that every person exhibits when tracking an object left to right, using eyes only, without head motion. There is a point in your peripheral vision gaze where your eyeballs will jerk because you have reached your maximum gaze position.
  • Intoxicated people's eyes usually jerk erratically a lot sooner than sober people's eyes do.
  • When a police officer administers the HGN test to you, he or she is carefully observing your eye movements as you follow a pen or finger held in front of you from left to right.
  • If the officer believes your eyes are jerking short of the average maximum peripheral gaze point, the next moments of your life may involve having handcuffs slapped to your wrists and hearing words, such as, "I am placing you under arrest on suspicion of drunk driving."
  • Many defendants challenge HGN results as evidence, especially if the officer who administered the test was not qualified to properly administer the test or espouse an official expert opinion regarding the interpretation of test results.

In addition to an HGN test, a police officer who has pulled you over may also ask you to take a walk-and-turn or other field sobriety test. You are not legally obligated to comply; however, if you refuse to take a chemical test, you may indeed incur automatic administrative penalties for your refusal, such as driver's license suspension or revocation.

It can be very difficult to remain calm when it's a police officer's word against yours regarding drunk driving charges. Just remember that the burden of proof lies with the state, the the presumption is that you are innocent unless proved otherwise and that you have the right to build a defense.

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Fisher Law Office

1322 Morro Street
San Luis Obispo, CA 93401-4028

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