What does the acronym HGN stand for in DUI testing?

The acronym HGN stands for Horizontal Gaze Nystagmus. This is a specific test used by law enforcement officers during DUI evaluations to assess a person's level of sobriety. The test measures the involuntary movement of the eyes as they follow a moving object, typically a pen or a flashlight. When a person is under the influence of alcohol or certain drugs, their eye movements may show distinct patterns, such as a lack of smooth pursuit or an exaggerated jerkiness, which are indicators of impairment.

Understanding the terminology is crucial for recognizing the procedures and effectiveness of field sobriety tests. The HGN test is considered one of the most reliable indicators of alcohol impairment when correctly administered, as established by various studies and research in the field of forensic science and DUI detection.