Walk-and-Turn Test: Procedure, Scoring Clues, and Accuracy

The walk-and-turn test is one of three standardized field sobriety tests the National Highway Traffic Safety Administration developed for roadside impairment checks. The officer asks you to stand heel-to-toe while listening to instructions, then take nine heel-to-toe steps along a line, pivot with small steps, and take nine steps back, all while counting out loud and keeping your arms at your sides. The officer watches for eight specific scoring clues, and showing two or more leads to a classification of likely impairment at or above 0.08 percent BAC. Used alone, the test identifies impairment correctly about 79 percent of the time.1National Highway Traffic Safety Administration. Standardized Field Sobriety Testing Refresher Participant Manual

Whether You Have To Take It

The walk-and-turn is voluntary. Field sobriety tests are not covered by implied consent laws in any state, so you face no automatic license suspension or statutory penalty for politely declining. Refusing does not mean the officer will send you on your way, though. If other observations point to impairment — slurred speech, the odor of alcohol, erratic driving — those alone can support an arrest and a request for chemical testing.

Chemical tests work differently. Refusing a breath or blood test after arrest triggers implied consent penalties in every state, typically an administrative license suspension regardless of whether you were actually impaired. Keep the two categories separate in your mind: the roadside balance test is optional, the post-arrest chemical test is not.

How the Test Is Set Up

The surface should be reasonably dry, hard, level, and non-slippery. NHTSA requires those conditions because uneven ground, gravel, or wet pavement can cause balance problems that have nothing to do with alcohol.2National Highway Traffic Safety Administration. Standardized Field Sobriety Test Participant Manual The area also needs enough light for you to see the line and for the officer to see your feet.

A straight line is part of the test. When no painted line or curb is available, officers may ask you to walk along an imaginary one.3National Highway Traffic Safety Administration. Standardized Field Sobriety Testing Instructor Guide An imaginary line is harder to walk and gives the officer more subjective room when deciding whether you stepped off it.

If you’re wearing heels taller than two inches, the officer should offer you the chance to take them off before the test starts.2National Highway Traffic Safety Administration. Standardized Field Sobriety Test Participant Manual Skipping that step matters later if the case reaches court.

The Instructional Stance

The test begins before you take a step. The officer tells you to put your left foot on the line and your right foot directly ahead of it, heel touching toe, with your arms at your sides. You hold that position while the officer explains the walking phase.2National Highway Traffic Safety Administration. Standardized Field Sobriety Test Participant Manual The stance is deliberately uncomfortable, and the officer is already scoring. Two of the eight clues come from this phase: breaking the stance to regain balance, and starting to walk before being told.

After explaining the full procedure, the officer is trained to ask, “Do you understand the instructions so far?”2National Highway Traffic Safety Administration. Standardized Field Sobriety Test Participant Manual That verbal check matters. Rushed instructions or a skipped confirmation give a defense attorney a specific protocol deviation to point to.

Walking and Turning

On the officer’s signal, you take nine heel-to-toe steps along the line, counting each step aloud. The heel of your front foot has to touch the toe of your back foot on every step. Arms stay at your sides. Eyes stay on your feet.2National Highway Traffic Safety Administration. Standardized Field Sobriety Test Participant Manual Nine out, nine back. The count is fixed.

The turn is where people most often slip up. You leave your lead foot planted on the line and use the other foot to take a series of small steps around it. Spinning, stepping backward, or lifting both feet off the line counts as an improper turn.2National Highway Traffic Safety Administration. Standardized Field Sobriety Test Participant Manual Then you walk nine more heel-to-toe steps back.

Keeping your arms pinned to your sides is part of the design, not an afterthought. It takes away your body’s natural balancing mechanism and makes the task meaningfully harder for anyone whose coordination is off. A sober person can usually manage it. Someone at or above 0.08 often cannot.

The Eight Scoring Clues

Officers grade the test on eight standardized clues. Two come from the instructional stance, six from the walking phase.4National Highway Traffic Safety Administration. Standardized Field Sobriety Testing Refresher Manual

  • Cannot keep balance during instructions. You break the heel-to-toe stance while the officer is still explaining.
  • Starts too soon. You begin walking before being told to.
  • Stops while walking. You pause mid-step to steady yourself.
  • Misses heel-to-toe. You leave a gap of more than half an inch between your heel and the toe of your other foot on any step.
  • Steps off the line. One or both feet move entirely off the line.
  • Uses arms for balance. You raise one or both arms more than six inches from your sides.2National Highway Traffic Safety Administration. Standardized Field Sobriety Test Participant Manual
  • Improper turn. You pivot, spin, or otherwise deviate from the small-steps turning technique.
  • Wrong number of steps. You take more or fewer than nine in either direction.

Each clue is counted once per test, not once per step. Missing heel-to-toe on four separate steps is still a single clue. All eight clues carry equal weight, and two is the threshold. Showing two or more means the officer classifies you as likely at or above 0.08 BAC.2National Highway Traffic Safety Administration. Standardized Field Sobriety Test Participant Manual If you cannot safely complete the test at all, the officer can stop it early and document the reasons, which itself becomes evidence of impairment.

How Accurate the Test Actually Is

NHTSA’s own research puts the walk-and-turn at 79 percent accuracy when used alone at the 0.08 threshold.1National Highway Traffic Safety Administration. Standardized Field Sobriety Testing Refresher Participant Manual The other side of that figure matters just as much. A 1998 NHTSA validation study found that among drivers whose actual BAC was below 0.08, officers still classified roughly 29 percent as at or above the legal limit based on field sobriety test performance.5National Highway Traffic Safety Administration. Validation of the Standardized Field Sobriety Test Battery at BACs Below 0.10 Percent Nearly one in three sober or under-the-limit drivers were misclassified, and defense attorneys use that false positive rate regularly to challenge the weight of walk-and-turn evidence.

The test was built around alcohol, and sensitivity drops for other substances. Research on cannabis-impaired drivers found the standard field sobriety battery identified about 67 percent of participants who met impairment thresholds, well below the detection rates for alcohol.6Canadian Centre on Substance Use and Addiction. Improving the Detection of Drivers Impaired by Cannabis: Supplementing the Standardized Field Sobriety Test

Physical Conditions That Produce False Clues

NHTSA’s training materials acknowledge the test’s limits. The original research found that people over 65 and those with back, leg, or inner ear problems had difficulty performing it regardless of sobriety. Knee injuries, hip replacements, neurological disorders, vertigo, and obesity can all produce clues that have nothing to do with alcohol. The manual specifically notes that the companion One-Leg Stand is unreliable for people 50 or more pounds overweight, and similar balance concerns carry over to the walk-and-turn.2National Highway Traffic Safety Administration. Standardized Field Sobriety Test Participant Manual

Officers are trained to account for these factors, but in practice accommodation depends on the individual officer. If you have a condition that affects your balance or mobility, say so before the test begins. That statement goes on the record and gives a defense attorney something concrete to point to later.

Challenging the Results Later

Walk-and-turn results are admissible in the overwhelming majority of jurisdictions. Officers can testify to what they observed, and that testimony can support both the probable cause for arrest and the prosecution’s case at trial. Courts have consistently held that the test cannot be used to prove a specific blood alcohol level, though. It indicates possible impairment. It does not measure BAC.

The most effective challenges target whether the officer followed NHTSA protocol. Common issues include:

  • Improper surface conditions, such as a slope, gravel, wet pavement, or grass instead of the dry, hard, level surface the protocol requires.
  • Inadequate instructions, including a missing demonstration, a skipped confirmation of understanding, or a rushed explanation.
  • Footwear not addressed when you were wearing heels over two inches.
  • Medical conditions ignored even though NHTSA acknowledges they can affect performance.
  • An imaginary line used when no visible one was available, making clues like “steps off the line” inherently subjective.
  • Scoring errors, where the officer recorded more clues than the evidence supports or misidentified a behavior as a clue.

When an officer deviates from the standardized procedure, most courts treat the error as affecting the weight of the evidence rather than making it inadmissible. The results still come in, but the jury or judge decides how much to trust them. Body camera footage, when available, is the single most useful tool for checking whether the officer administered and scored the test correctly.