New Jersey DUI Attorney Discusses the Field Sobriety Vision Test, Also Known as the Horizontal Gaze Nystagmus Test

Horizontal Gaze Nystagmus TestIf you are pulled over and arrested for DWI in New Jersey, the police have a few options for proving that you were driving under the influence of alcohol or drugs. Two of the things that police officers may do is (1) conduct a field sobriety test, or (2) use an official breathalyzer test, which is meant to determine scientifically if your blood alcohol content (BAC) is over the legal limit of .08%. Because the government is required to adhere to specific and complicated guidelines for administering and maintaining BAC tests and records, it is important that you retain an experienced attorney if you are ever arrested for a DUI. A knowledgeable DUI/DWI attorney will be able to review the records and may be able to have the BAC evidence thrown out so that it cannot be used against you.

If the BAC evidence is thrown out, or otherwise compromised or excluded, then the government will be required to rely on other evidence to prove that you were driving under the influence of alcohol or drugs, such as the field sobriety test. A police officer’s observations and notes regarding how a driver acts or appears, when combined with evidence of the officer’s experience in assessing impairment, can be used to convict a driver of operating a motor vehicle under the influence of drugs or alcohol.

Horizontal Gaze Nystagmus Test

In New Jersey, police officers may ask a driver to do a number of different exercises in an attempt to determine if the person is intoxicated, under the influence of any substances, or otherwise impaired, including standing on one leg, reciting the alphabet backwards, walking in a straight line, or following the police officer’s finger with the person’s eyes. Not all of the tests are admissible in court. The vision test, where a driver is asked to move his or her eyes from side to side, is considered scientifically reliable under the law. This is called the Horizontal Gaze Nystagmus (HGN) test.

Nystagmus is a term to describe fast, uncontrollable movements of the eyes – sometimes also referred to as dancing eyes. Impairment due to alcohol and the use of certain drugs can cause involuntary nystagmus. Accordingly, in the 1970’s and 1980’s, the National Highway Traffic Safety Administration (NHTSA) performed studies to determine if the HGN could be used to reliably determine if a person was operating a car while intoxicated or impaired by drugs, and the studies found the HGN test is 77% accurate in determining whether a person has a 0.10 BAC or more.

What Police Officers Are Looking for When Performing the Test

Police officers are provided with some training in how to perform an HGN test, including what signs of impairment to look for. The guidelines suggest that a police officer is checking for equal pupil size and whether the eyes are jerking involuntarily from side to side while at rest or while tracking an object from side to side. Three specific “clues” that officers are trained to look for include:

  1. The lack of smooth movement from side to side – bouncing rather than rolling smoothly.
  2. Distinct and sustained nystagmus when the eyes are held at maximum deviation and held for a minimum of four seconds.
  3. Onset of nystagmus when the eyes have moved less than 45 degrees to the side.

How a Lawyer May Challenge the Horizontal Gaze Nystagmus Test

Scientific and medical experts have concerns that the administration of the HGN test by police officers may be unreliable because these officers are not ophthalmologist, trained in the detection of eye movements and or eye pathologies. Some experts have also suggested that the NHTSA standards for performing the HGN test could lead to false results. One independent study concluded that, in a controlled laboratory test, police officers were wrong 41% of the time about whether a person with a .10% BAC experienced HGN.

Similarly, HGN can be caused by a number of other things, including injury, tiredness, illness, or medical conditions. In the case of Schultz v. State, a case from Maryland, the court recognized at least 38 medical conditions unrelated to alcohol that can cause HGN, including the flu, consumption of excessive amounts of caffeine, head trauma, some prescription drugs, and exposure to certain chemicals or toxins.

Because a police officer is looking at your behavior, appearance, and how you perform on these tests, your performance on any field sobriety test, as well as your ability to speak to the police officer and answer questions, can help in your defense against a DUI/DWI conviction. At the end of the day, these tests are not perfect and subject to human error. For that reason, it is important to always consult an experienced lawyer. A DUI attorney may be able to fight the charges against you or have the charges dismissed completely.

New Jersey DUI/DWI Attorney Edward M. Janzekovich Can Help if You Are Arrested for Drunk Driving

An arrest for driving under the influence of alcohol or drugs can have life-changing consequences for any driver. Such a charge, and possible trial, can also be extremely complicated, especially when specific tests or scientific evidence is involved. If you are charged with drunk driving or driving under the influence of any substance in New Jersey, an experienced DWI/DUI attorney can make all the difference. To speak with an experienced New Jersey DWI lawyer about your situation, call us at 732-257-1137 or contact us online today. We serve clients throughout the state of New Jersey.