Criminal Defense in Orange County

Was the Horizontal Nystagmus Test Administered Correctly?

One of the primary tools used by officers in a DUI arrest is field sobriety tests such as the horizontal gaze nystagmus. The horizontal gaze nystagmus test is one of the few field sobriety tests verified for accuracy by the National Highway Traffic Safety Administration (NHTSA). This test seems relatively straightforward—the suspect is asked to track a beam of light that the officer moves back and forth with his pocket flashlight. The officer watches to see if the suspect's eye movement is smooth or if he displays nystagmus, which is the involuntary jerking of the eye.

All people will display some nystagmus at some point during the test, usually when the beam of light is about 40 degrees from dead-on. However, alcohol is known to make this nystagmus happen sooner and more dramatically. If the arresting officer claims that you have failed a horizontal gaze nystagmus test, an Orange County DUI defense attorney can still fight your charges. The validity of a test depends on the proper administration of it, the qualifications of the officer administering it, and corroboration by other tests. If your lawyer can find issue with any of these factors, the test may be rendered invalid.

Even with all of those factors check out, it is important to remember that the horizontal gaze nystagmus test is only 77% accurate. With this in mind, your attorney can introduce reasonable doubt to the state by pressing these factors during cross-examination. They may ask the officer to recount every step he took when administering the test, and if the officer is unable to recall any part of the procedure, reasonable doubt could be introduced. They may ask an unqualified officer about his qualifications or ask that the officer verify that he failed to corroborate the results of the test.

Creating Reasonable Doubt During Cross-Examination

The procedure for administering the horizontal nystagmus test has 25 separate steps. As a result, many officers make mistakes. However, most would never admit to making a mistake if asked directly. Luckily, there is a simple method commonly employed by defense attorneys to garner such an admission. During cross examination, they can ask the officer about each step in the procedure and emphasizes every point where the officer claims to forget or be unsure.

These questions may be about:

  • Specific details regarding the procedure of the tests
  • The officer's preparation for the test
  • The objects that the officer used during the test
  • The directions they gave to the defendant during the test

Your Orange County DUI lawyer may also intersperse questions about common mistakes among questions about proper test procedure, just to make sure the officer is not just mindlessly confirming his answers. Ironically, the officer could do everything perfectly while administering the horizontal gaze nystagmus test and the results could still be inaccurate. Numerous medical conditions can cause a false positive on the horizontal nystagmus test, such as fatigue, hypertension, and caffeine usage.

This horizontal gaze nystagmus test is an essentially a medical exam, and the person administering it needs the medical expertise to differentiate an aberrant level of nystagmus from a natural one. The person must also take into account other potential causes of aberrant nystagmus besides alcohol. Because of this, it is possible to attack an arrest based on the results of this test by illustrating the officer's lack of medical expertise to the jury. The Law Office of Barney B. Gibbs knows this tactic and others like it, so you can trust that will give you a fair chance at fighting your DUI charges.

Failing a field sobriety test is not a death sentence for your case. An experienced attorney can still fight the charges. Call The Law Offices of Barney B. Gibbs today for a free initial consultation.