Procedure:
(1) The subject is asked to take 9 steps along a straight line, with the steps taken heel--to-toe.
(2) The person turns 180 degrees after the 9 steps are taken, and returns in the same manner to the starting point.
During the test the person takes a total of 18 steps with 1 turn.
Clues to impairment:
(1) The person cannot keep his or her balance while listening to the instructions.
(2) The person starts before the instructions are finished.
(3) The person has to stop to regain his or her balance.
(4) The person has to put out his or her arms to regain balance.
(5) The person steps off the line.
(6) The person does not walk heel-to-toe.
(7) The person makes an improper turn.
(8) The person takes an improper number of steps either coming or going.
If the person is unable to perform the test then the person is assumed to have all 8 clues.
Interpretation:
• minimum number of clues: 0
• maximum number of clues: 8
• A person with 2 or more clues has a 79% chance of having a blood alcohol concentration (BAC) >= 0.08 g/dL.
• A field sobriety test by itself does not mean that the person is intoxicated. It does provide "reasonable cause" to conduct further testing including a determination of the blood alcohol concentration.
