Name two common standardized field sobriety tests.

• A. Breathalyzer and Drager test.
• B. Finger-to-nose and rapid counting.
• C. Horizontal Gaze Nystagmus (HGN) and Walk-and-Turn (or One-Leg Stand).
• D. Vertical gaze tracking and balance test.

Answer: (C)

Field sobriety tests are quick, behavioral ways officers assess impairment on the spot. The two most widely used standardized tests are the horizontal gaze nystagmus (HGN) test and the walk-and-turn test. The HGN test looks for involuntary eye jerks as the eyes track a moving stimulus; alcohol tends to induce nystagmus at certain angles, so observing the eye movements gives observable impairment clues. The walk-and-turn test evaluates balance and the ability to follow instructions by having the person walk heel-to-toe along a line, turn, and return, which taxes balance and divided attention. Sometimes the one-leg stand is used as an additional balance/attention measure. These tests are standardized in how they’re administered and scored, which is why they’re the typical pair (with the option of including a third) in the field sobriety assessment. Other options described involve chemical analysis or nonstandard tasks, so they aren’t part of the standard SFST battery.