Arizona Horizontal Gaze Nystagmus (HGN) Practice Exam and Study Guide

The roadside breathalyzer is not part of the standardized field sobriety tests (SFSTs) protocol. The SFSTs, which are widely used for assessing driving impairment, include the horizontal gaze nystagmus test, the one-leg stand, and the walk-and-turn test. These assessments are designed to measure physical and cognitive functions indicating impairment, such as balance, coordination, and the ability to follow instructions.

In contrast, a roadside breathalyzer is a tool used to measure blood alcohol concentration (BAC) directly from breath samples. While it plays a crucial role in the overall process of identifying intoxicated drivers, it is not considered a behavioral or physical test like the standardized field sobriety tests. Therefore, the distinction lies in the nature of these tests: SFSTs are observational and performance-based assessments, whereas a breathalyzer provides a quantifiable measurement of alcohol levels.