What is the primary purpose of the One Leg Stand test?

The primary purpose of the One Leg Stand test is to evaluate balance and counting ability, which are both indicative of a person's coordination and motor skills. This test is particularly useful in DUI traffic stops because alcohol consumption can significantly impair these abilities. During the test, the individual is asked to stand on one leg and count aloud for a certain duration.

The ability to maintain balance while performing a mental task, such as counting, is assessed to determine if the individual shows signs of impairment. If a person struggles to balance or cannot stay focused on the counting, it suggests that their physical and cognitive functions are compromised, which is a strong indicator of intoxication.

This focusing on balance and counting provides a clear, observable method that officers can use to make informed judgments about the potential sobriety of a driver during a traffic stop.