The walk and turn test is one of the FST’s recommended by the NHTSA. Like many FST’s, this is a divided attention test. The first phase of the tests consists of instructions on how to perform the test by the officer. The officer will instruct the suspect to stand on a line with his/her feet in a heel-to-toe position. While standing in this position, the officer will provide further instructions on how to complete the test. According to NHTSA studies, individuals who are under the influence of alcohol will not be able to hold this position and listen to the instructions without losing their balance or beginning the test before the instructions are completed.
The second phase of the tests consists of the actual performance of the walk and turn. The officer will ask the subject to take nine steps heel-to-toe down a straight line, turn, and take nine heel-to-toe steps back down the line to the starting position. Generally, the turn must be performed by keeping one foot on the ground and making a series of small steps with the other foot.
It is best to have the test completed on smooth level ground, which rarely occurs in DUI investigations. In addition, it is preferable to use a real line, but an officer may instruct the suspect to walk an imaginary line. Finally, other factors may affect the ability of a suspect to perform this test include weather, lighting, police lights, and noise, wind, and lights from oncoming traffic.
There are eight clues that an officer will look for when evaluating the walk and turn case: 1) balance during instruction phase; 2) starting the test before the instructions are finished; 3) stopping while walking; 4) not touching heel to toe; 5) stepping off of the line; 6) using arms for balance; 7) losing balance or turning incorrectly; 8) taking the wrong number of steps.
According to NHTSA studies, if two or more clues are present, then there is a 68% chance that the suspect has a BAC of more than .10%. However, if additional tests are performed, the number goes up significantly.
