By Erin Gerstenzang

The Walk-and-Turn is a common roadside field sobriety test that is easy to discount if you do not understand how it is designed or what the DUI officer is trained to look for.

Although it may seem like there is not much to it, the test itself is very detailed and complex, and drivers frequently believe they performed better than the officer’s scorecard will reflect.

Understanding the Mechanics of the DUI Walk-and-Turn

Before beginning the test, the officer is required to medically qualify the driver because not everyone is a good candidate for the test. Certain physical conditions can prevent fair testing.

Research shows that people who meet the following criteria will struggle to complete the test even without alcohol:

  • Those with leg, back, or inner ear problems
  • Those over the age of 65
  • Those who are 50 + pounds overweight
  • Those wearing heels over 2″ (according to research, the shoes should be totally removed. But, according to law enforcement, the driver should be given the opportunity to remove them)

DIrections of the DUI Walk-and-Turn Test

DUI officers are required to provide specific instructions prior to beginning this test. And sometimes they count it as a “clue” of impairment when the driver begins the test before being instructed to start. However, this should not be counted against the driver until after she has acknowledged to the officer that she understands the instructions.

First, the officer will designate a straight line that may be either real or imaginary. Then, the officer should tell the driver to place their left foot on the line, right foot in front of the left, touching heel-to-toe.

Next, the officer should tell the driver to place their arms by their side and not to start until told to do so. The officer should demonstrate these instructions at the same time. Before moving on, the officer should ask the person if they understand the directions and they must get an affirmative answer.

There are two clues the officer looks for during this stage. First, they are looking to see if the driver starts the test too soon. It’s common for the person to immediately get into the heel-to-toe stance and start walking before they are instructed not to. But according to the testing protocol, this cannot be counted as a clue if the driver starts before the officer instructs tells them not to.

The second clue at the instructional stage is when the driver does not keep her balance while listening to instructions. If she is swaying and raising their arms, it’s not a clue.  But, if she breaks the heel-to-toe stance, that is considered a clue.

The officer is trained to tell the driver to take nine heel-to-toe steps on the line, turn around keeping one foot on the line, and return nine steps heel-to-toe when told to begin. Then, the officer should demonstrate these instructions with at least three heel-to-toe steps.

The officer should also instruct the driver to look down at their feet, count each step out loud, keep their arms to their side without raising them, and not to stop until the test is complete. Again, the officer is required to ask the person if they understand and wait for an affirmative response before proceeding.

How is this test scored?

The WAT has a total of 8 possible ways the driver can make a mistake – resulting in the officer observing a “clue.” If the officer observes 2 of the 8 clues, then this will support her decision to arrest the driver. The other clues she is looking for include whether the driver raises his arms stops while walking, does not touch heel-to-toe on every step, steps offline, takes an improper number of steps or turns improperly.

The eight possible clues the officer will look for:

  1. The driver starts the test too soon
  2. The driver does not remain in the starting position
  3. The driver stops once they begin
  4. The driver misses touching heel-to-toe by half an inch or more
  5. The driver steps off the line completely
  6. She raises her arms for balance at a height of six inches or more
  7. She makes an improper turn
  8. She takes an incorrect number of steps

Why are people walking a straight line to test sobriety in DUI cases?

The government claims these tests are mostly reliable, based on studies performed decades earlier. One of the most cited DUI roadside testing studies is the “Validation of the Standardized Field Sobriety Test Battery at BACs Below .10 percent” from 1998, when the San Diego DUI task force was recruited to help study the reliability of roadside tests.

Officers were instructed to apply the three standardized field sobriety tests when they encountered anyone they suspected of DUI. They noted their observations, how many clues were present, and whether or not they would make an arrest. Then, they matched the officer’s arrest decision with the person’s blood alcohol concentration to determine how accurate the tests were using the specific standards for each test.

The standard for the HGN was four or more clues to indicate a person’s BAC was .10 or higher.  For the Walk-and-Turn and the One-Leg Stand, the standard was two or more clues.

If the person met the number of standard clues and the BAC was above the legal limit, it was considered a correct DUI arrest decision. But if the person had below the required number of clues, or above that number with a low BAC, it was considered an incorrect arrest decision.

According to the study, when the three standardized field sobriety tests were combined they were 91% reliable in determining if a person was at or above the (at the time) legal limit of .10. When you break it down, the HGN was 88% reliable with four or more clues, the Walk-and-Turn was 70% reliable with two or more, and the One-Leg Stand was 83% reliable when two or more clues were present.

However, this study was not peer-reviewed. And when you dissect the numbers, there are major issues. For example, when you look at the number of false positives, you can find serious problems with the reliability of these tests. For HGN, the percentage of false positives in people who exhibited four or more clues was 37%. For the Walk-and-Turn, the percentage with two or more clues was 52%. And the One-Leg stand had a false positive rate of 41% even when two or more clues were present.

When you look at the number of false positives, despite the study claiming these tests are reliable, you can find good places to challenge the standardized field sobriety tests.