The walk-and-turn is a divided-attention test administered under NHTSA standards. During instructions the subject stands with the right foot in front of the left, heel to toe, arms at the sides, and listens without moving. The walking phase requires nine heel-to-toe steps down a real or imaginary line, a specified turn using a series of small steps, and nine steps back. Eight clues are scored: cannot keep balance during instructions, starts too soon, stops walking, missed heel-to-toe, steps off line, uses arms for balance, improper turn, and wrong number of steps. Two or more clues indicates impairment. Age, injury, weight, footwear, and slope all affect validity. A Chicago DUI lawyer targets each NHTSA element.
