Police Dispatcher Practice Test 2026 – The Comprehensive All-in-One Guide for Exam Success!

The term H.G.N. stands for Horizontal Gaze Nystagmus, which is a physiological phenomenon observed in individuals. In the context of drug and alcohol detection, it refers to an involuntary eye movement that can indicate impairment. When a person is under the influence of alcohol or certain drugs, their ability to maintain steady eye movement when following a moving object can be affected.

Law enforcement officers utilize Horizontal Gaze Nystagmus as part of standardized field sobriety tests to assess a person’s level of intoxication. The assessment involves checking how smoothly the eyes can track a stimulus, such as a pen or a finger, and looking for signs of jerking or involuntary movement, which can suggest impairment due to substance use. This method is scientifically validated and helps in forming part of a larger evaluation to determine if a driver is unfit to operate a vehicle.

The other options do not relate to established methods of assessing drug or alcohol influence, making them less relevant in this context. Harmful Gas Notification and Hazardous Goods Notification pertain to public safety concerning chemical exposure, while Homegrown Narcotic Guidelines would not be a recognized term in the field of drug detection.