DUI standardized field sobriety tests
The walk and turn test is one of three field sobriety tests that have been “standardized” by the National Highway Traffic Safety Administration. The three are:
Administration of the test
The suspect stands in a heel-to-toe fashion with arms at the sides while a series of instructions are given. Then, the suspect must take nine heel-to-toe steps along a line, turn in a prescribed manner, and take another nine heel-to-toe steps along the line. All of this must be done while counting the steps aloud and keeping the arms at the sides. The suspect should not stop walking until the test is completed.
The officer is instructed to give the test as follows:
- Tell suspects to place their left foot on the line.
- Tell suspects to place the right foot on the line, in front of the left foot, with the heel of the right foot against the toe of the left foot. Demonstrate the heel-to-toe stance.
- Tell suspects to put their arms down against their sides (Demonstrate), and to keep them there throughout the entire test.
- Tell suspects that they are to maintain this position while you give the instructions. Emphasize that the suspect must not start walking until you say to “begin.”
- Ask suspects if they understand. (Make sure suspects indicate “yes.”)
- Tell suspects that every time they take a step, the heel must be placed against the toe of the other foot. Demonstrate several heel-to-toe steps.
- Tell suspects that when the ninth step has been taken, they must leave the front foot on the line, and turn around using a series of small steps with the other foot. Demonstrate a proper turn.
- Remind suspects that, after turning, they must take another nine heel-to-toe steps up the line.
- Tell suspects that they must watch their feet at all times, must count the steps aloud, and must keep the arms down at the sides.
- Tell suspects that, once they start walking, not to stop walking until the test has been completed.
- Ask suspects if they understand.
- Tell the suspect to “begin.”
The officer is also given the following instructions:
- If at any time while you are giving the rest of the instructions the suspect should break away from the heel-to-toe stance, stop giving instructions until he or she resumes the stance. Tell the suspect that, when you say to “begin,” they must take nine heel-to-toe steps down the line, turn around, and take nine heel-to-toe steps up the line.
- If the suspect fails to either look at their feet or count their steps aloud, remind the suspect to do so and note the occurrence on the evaluation form. These tasks are part of the validated clues and must be performed to properly evaluate divided attention.
Scoring the test
The Walk and Turn test has eight clues of impairment. Two clues apply while the suspect is standing heel-to-toe and listening to the instructions:
- Can not keep balance (i.e., suspect breaks away from the heel-to-toe stance). Swaying or using arms for balance is not considered a clue at this point.
- Starts too soon (i.e., suspect starts walking before you say “begin”).
The other six validated clues apply during the walking stage of the test. They are:
- Stops walking (i.e., the subject pauses for several seconds).
- Misses heel-to-toe (i.e., more than 1/2 inch gap).
- Steps off the line (i.e., the foot must be entirely off the line).
- Raises the arms while walking (i.e., more than 6 inches).
- Takes the wrong number of steps.
- Turns improperly.
Two or more clues classify the suspect’s blood alcohol concentration (BAC) as above a 0.10%.
Test requirements and possible errors
The officer is warned that this test requires a designated straight line and should be conducted on a reasonably dry, hard, level, non-slippery surface.
In addition, the officer is told that original research indicated that individuals over the age of 65, and those with back, leg or middle ear problems had difficulty performing the test. Subjects wearing heels more than 2 inches high should be given the opportunity to remove their shoes.