Walk and Turn
The San Francisco Police Department Driving Under the Influence Manual explains that the Walk and Turn Field Sobriety Test is a divided attention test. The test requires a person driver suspected of driving under the influence to divide attention among mental and physical tasks. The mental tasks include comprehending verbal instructions, processing information, and recall. The physical tasks include balance and coordination. During the test the suspect is required to maintain balance and coordination while standing still, while walking and while turning.Instructional Phase
The Walk and Turn is a Standardized Field Sobriety Test which is not favored by California Highway Patrol Officers and other law enforcement officers because it places a lot of distance between the officer the the DUI suspect. On the shoulder of the freeway this can be dangerous to the driver, as well as limiting the officer's ability to view performance from the side.
The instructional phase of the Walk and Turn involves instructing the driver to place the left foot on a real or imaginary line. The driver is then told to place the right foot on the line ahead of the left foot with the heel of the right foot against the toe of the left foot. The officer administering this Field Sobriety Test is to demonstrate it for the DUI suspect. Next the driver is instructed to place their arms down at their side and told to maintain the position until the officer tells the driver to begin.
During the instructional phase of the Walk and Turn Field Sobriety Test, the DUI suspect must be able to maintain balance while standing heel to toe and simultaneously listen to and comprehend the test instructions. The officer may report that the driver failed to do what was asked.
The driver is reminded not to start walking until told to begin and asked it the instructions are understood. The officer is required to demonstrate the Walk and Turn tells the driver, "When I tell you to start, take nine heel to toe steps, turn and take nine heel to toe steps back." Three steps are demonstrated for the DUI suspect.
Performance Phase
The Walk and Turn Standardized Field Sobriety test requires a designated straight line and should be conducted on a reasonably dry, hard, level, nonslippery surface. Drivers being investigated for driving under the influence should be allowed sufficient room to complete nine heel to toe steps. Any driver wearing shoes having heels of more than two inches should be given an opportunity to remove them.
In the performance phase, the drive must take nine steps heel to toe on the line, turn around as instructed, and take nine steps returning from the point where the test began.
Scoring Performance
The below listed clues are most likely to be present in a driver having a blood alcohol level of 0.10 percent or higher. Four or more cues will result in the officer rendering the opinion that the driver was under the influence.
- Cannot keep balance while listening to the instructions
- Starts before the instructions are finished
- Stops walking
- Does not touch heel to toe
- Steps off the line
- Uses arms for balance
- Makes an improper turn
- Takes an incorrect number of steps
Combined Interpretation of Walk and Turn test and Horizontal Gaze Nystagmus
The DUI Enforcement Manual represents that combining four or more clues of the Horizontal Gaze Nystagmus test with two or more clues of the Walk and Turn test yields an accurate classification of above 0.10 percent Blood Alcohol Concentration 80 percent of the time.