What action would indicate the suspect is invalidating the One-Leg Stand test?

The action that indicates a suspect is invalidating the One-Leg Stand test is using arms for balance. In this test, an individual is asked to stand on one leg while keeping the other leg elevated and the arms placed at their sides. The absence of the use of arms for balance is critical to accurately assess a suspect's ability to maintain their balance, which is a key indicator of potential impairment due to alcohol or other substances.

When a suspect uses their arms to assist with balance, it suggests they may not be able to perform the task as required, thereby signaling a lack of balance and coordination. This is significant because the test is designed to evaluate these specific abilities in a controlled manner. If an individual uses their arms, the results may not accurately reflect their capabilities, rendering the performance invalid in determining impairment.

Maintaining balance for over 30 seconds would actually indicate a strong performance, while following verbal instructions is part of test compliance. Walking a straight line is not part of the One-Leg Stand test and relates to a different assessment of physical coordination and agility. Thus, using arms for balance is the most direct violation of the test parameters.