9.5.4 Walk and Turn
The second test that is typically administered is the Walk and Turn
18.104.22.168 Procedures for Walk-and-Turn Testing
1. Instructions Stage: Initial Positioning and Verbal Instructions 
For standardization in the performance of this test, have the suspect assume the heel-to-toe stance by giving the following verbal instructions, accompanied by demonstrations:
"Place your left foot on the line” (real or imaginary). Demonstrate.
"Place your right foot on the line ahead of the left foot, with heel of right foot against toe of left foot." Demonstrate.
"Place your arms down at your sides." Demonstrate.
"Maintain this position until I have completed the instructions. Do not start to walk until told to do so."
"Do you understand the instructions so far?" (Make sure suspect indicates understanding.)
2. Demonstrations and Instructions for the Walking Stage
Explain the test requirements, using the following verbal instructions, accompanied by demonstrations:
"When I tell you to start, take nine heel-to-toe steps, turn, and take nine heel-to-toe steps back." (Demonstrate 3 heel-to-toe steps.)
"When you turn, keep the front foot on the line, and turn by taking a series of small steps with the other foot, like this." (Demonstrate).
"While you are walking, keep your arms at your sides, watch your feet at all times, and count your steps out loud."
"Once you start walking, don't stop until you have completed the test."
"Do you understand the instructions?" (Make sure suspect understands.)
"Begin, and count your first step from the heel-to-toe position as 'One.'"
22.214.171.124.2 Test Interpretation
“You may observe a number of different behaviors when a suspect performs this test. Original research demonstrated that the behaviors listed below are likely to be observed in someone with a BAC above 0.10. Look for the following clues each time this test is given:
A. Cannot keep balance while listening to the instructions. Two tasks are required at the beginning of this test. The suspect must balance heel-to-toe on the line, and at the same time, listen carefully to the instructions.
Typically, the person who is impaired can do only one of these things. The suspect may listen to the instructions, but not keep balance. Record this clue if the suspect does not maintain the heel-to-toe position throughout the instructions. (Feet must actually break apart.) Do not record this clue if the suspect sways or uses the arms to balance but maintains the heel-to-toe position.
B. Starts before the instructions are finished. The impaired person may also keep balance, but not listen to the instructions. Since you specifically instructed the suspect not to start walking "until I tell you to begin," record this clue if the suspect does not wait.
C. Stops while walking. The suspect pauses for several seconds. Do not record this clue if the suspect is merely walking slowly.
D. Does not touch heel-to-toe. The suspect leaves a space of more than one-half inch between the heel and toe on any step.
E. Steps off the line. The suspect steps so that one foot is entirely off the line.
F. Uses arms to balance. The suspect raises one or both arms more than 6 inches from the sides in order to maintain balance.
G. Improper turn. The suspect removes the front foot from the line while turning. Also record this clue if the suspect has not followed directions as demonstrated, i.e., spins or pivots around.
H. Incorrect number of steps. Record this clue if the suspect takes more or fewer than nine steps in either direction.
Note: If suspect can't do the test, record observed clues and document the reason for not completing the test, e.g. suspect’s safety.
If the suspect has difficulty with the test (for example, steps off the line), continue from that point, not from the beginning. This test may lose its sensitivity if it is repeated several times.
Observe the suspect from a safe distance and limit your movement which may distract the suspect during the test. Always consider officer safety.
“Based on original research, if the suspect exhibits two or more clues on this test or fails to complete it, classify the suspect's BAC as above 0.10. Using this criterion, you will be able to accurately classify 68% of your suspects.” So, 2 clues out of 8 is a failure.
126.96.36.199.3 Test Conditions
“Walk-and-Turn test requires a designated straight line, and should be conducted on a reasonably dry, hard, level, nonslippery surface. There should be sufficient room for suspects to complete nine heel-to-toe steps. Note: Recent field validation studies have indicated that varying environmental conditions have not affected a suspect’s ability to perform this test.”
Images from NHTSA, in public domain.
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