When suspected of driving under the influence (DUI), you may be subjected to various field sobriety tests by law enforcement. Among these, the Horizontal Gaze Nystagmus (HGN) test is a commonly used method to detect signs of impairment.
Understanding how this test is conducted and its implications can be crucial if you ever find yourself in such a situation. Contact Chambers Law Firm at 714-760-4088 for a free legal consultation.
What is the Horizontal Gaze Nystagmus Test?
The HGN test involves observing the eyes’ involuntary jerking as they follow a moving object such as a pen or a small flashlight. Nystagmus, or the jerking of the eye, is a natural, involuntary movement that can become pronounced under certain conditions, including alcohol impairment.
Conducting the HGN Test
Preparation
Before administering the test, officers typically ensure that external factors do not influence the results. This preparation includes facing you away from distractions such as passing car headlights or direct lights from the police vehicle that might exaggerate eye jerking.
Health Screening
The officer may inquire about any use of contact lenses or glasses and will ask about any existing medical conditions. Conditions that affect the eyes or neurological functions can influence the outcome of the test, and it’s vital that the officer is aware of these to avoid misinterpretation of the results.
Test Procedure
To conduct the HGN test, the officer will ask you to track the movement of a small object with your eyes. The officer holds the object approximately 12 to 15 inches from your face and moves it horizontally while observing your eye movements. The test checks for three specific signs:
- The eye cannot follow the object smoothly.
- Distinct jerking when the eye is at maximum deviation (farthest from the center).
- Onset of jerking before the eye reaches a 45-degree angle.
Accuracy and Reliability of the HGN Test
The HGN test is regarded by the National Highway Traffic Safety Administration (NHTSA) as one of the more reliable field sobriety tests, with studies indicating an accuracy of approximately 77%. However, it’s important to recognize that several non-alcohol-related factors, such as certain medical conditions, can cause nystagmus. This factor can complicate the test’s reliability, leading to potential false positives.
Legal Implications of Failing the HGN Test
Failing the HGN test can lead to DUI charges, which might seem daunting. The presence of nystagmus can be attributed to a variety of factors unrelated to alcohol consumption, including inner ear disorders, various neurological disorders, and even genetics.
Why Legal Representation is Essential
If you are charged with a DUI based on an HGN test or any other field sobriety tests, it is crucial to seek competent legal representation. An experienced DUI defense attorney can:
- Challenge the administration and interpretation of the HGN test.
- Provide insight into other medical or environmental factors that could have influenced the test results.
- Help navigate the complexities of DUI charges and potentially mitigate the consequences.
Given the potential for the HGN test to be influenced by factors other than alcohol, having an attorney who understands the nuances of such tests is invaluable. They can argue against the reliability of the results and present a defense based on a comprehensive understanding of both the law and the science behind field sobriety tests.
If you face DUI charges or have questions about the HGN test, contact Chambers Law Firm at 714-760-4088 for a free consultation. Our knowledgeable team is prepared to offer the guidance and representation needed to address these charges effectively.
