In what stage of the One Leg Stand test must the subject maintain balance for 30 seconds?

The One Leg Stand test is designed to assess a subject's ability to maintain balance while following instructions. During this test, the subject is required to stand on one leg and maintain that position for 30 seconds. The correct answer involves the demand for both balance and the cognitive task of counting, which together evaluate the individual's motor skills and mental processing simultaneously.

In the Balance and Counting stage, the subject must not only focus on maintaining their stance on one leg but also count out loud by stating numbers sequentially. This dual task makes the assessment more challenging and effective, as it simulates real-world situations where a driver must be able to multitask while also maintaining their stability. The requirement to balance for that full 30-second duration is crucial for determining potential impairment.

While other stages may involve aspects of balance or counting, only the Balance and Counting stage integrates both elements for the full duration necessary to properly assess the subject's sobriety.