In this test, the officer will instruct the test subject to stand with their feet flat on the ground, heels and toes touching, arms at their side and to remain in that position until being told to begin. The officer will tell the subject that when told to begin, he or she is to raise one of their feet about six inches above the ground in front of them with their leg being extended in a straight fashion. The subject is told to then hold their foot aloft, keep their hands at their sides, look at the toe of the elevated foot and then count out loud to 30. Even if the officer dictates the instructions perfectly, he has given the test subject at least six assignments to perform and has only taken a few seconds to give the instructions.

The test subject is required to recall each instruction given regardless of the brevity of the instruction, the weather or surface conditions present, and to perform each test exactly as instructed. This can be incredibly difficult, even for a person who has consumed no alcohol at all.

Beginning the test before being told, dropping the elevated foot while counting, failing to look at the extended foot, failing to count out loud, losing count or using one’s arms for balance are all reasons for the officer to assess the test as a failure.