What action must the subject take when performing the Walk and Turn test?

The action that the subject must take when performing the Walk and Turn test includes counting aloud while stepping. This requirement serves multiple purposes: it helps to ensure that the subject is focused and engaged in the task, which can be an indicator of their cognitive functioning and balance. The act of counting assists the officer in observing any discrepancies in the individual's ability to walk and maintain balance, as difficulties with these tasks may suggest impairment due to alcohol or drugs.

Furthermore, the ability to count aloud requires a level of coordination and cognitive processing that can be more challenging for someone under the influence. This emphasis on verbalizing the process as they perform it is key in assessing the subject's overall coordination, balance, and attentiveness during the test.