What should an officer conclude if nystagmus is not observable during the HGN test?

If nystagmus is not observable during the Horizontal Gaze Nystagmus (HGN) test, it suggests that there are no indications of alcohol impairment based on the specific eye movement response being evaluated. The HGN test measures the involuntary jerking of the eyes as they move from side to side, and the presence of nystagmus generally indicates possible intoxication.

When nystagmus is absent, it provides an important signal that the driver may not be under the influence of alcohol to the point where it affects this specific function. This context is critical because the HGN test is designed to detect signs of impairment due to alcohol. While the absence of nystagmus does not conclusively prove that a driver is entirely sober or that they haven't consumed other substances, it does indicate a significant lack of evidence supporting the idea that they are impaired by alcohol.

This understanding aids officers in making informed decisions about whether further assessments might be necessary or whether the driver may be free to continue their driving.