The Walk-and-Turn Test: How It Works and Why It Is Easy to Fail Sober

What the walk-and-turn measures

The walk-and-turn is what researchers call a divided-attention test. It asks you to do two things at once: keep your balance in an awkward heel-to-toe stance and follow a set of multi-step instructions. That is meant to mirror the divided attention that driving requires. The problem is that the same divided-attention demand is exactly what is degraded by fatigue, anxiety, and the stress of a roadside stop, so a sober but exhausted or nervous person can produce the same errors an officer scores as impairment.

The 14 instructions you have to hold in mind

Researchers count 14 separate things a subject must remember and do during the walk-and-turn, from keeping your arms at your sides and not beginning until told to start to counting each step out loud and watching your feet at all times. That memory load is the point. The test is designed to divide your attention, which is also why an anxious, tired, or distracted sober person produces the same errors an officer scores as impairment.

How the test works and the eight clues

The test has two phases. In the instruction phase, you stand with one foot directly in front of the other, heel-to-toe, with your arms at your sides, while the officer explains and demonstrates the test. In the walking phase, you take nine heel-to-toe steps along a real or imaginary line, turn as instructed by taking a series of small steps, and take nine heel-to-toe steps back.

The officer watches for eight clues:

• Cannot keep balance during the instructions.
• Starts before the instructions are finished.
• Stops while walking.
• Does not touch heel to toe.
• Steps off the line.
• Uses arms for balance.
• Turns improperly.
• Takes the wrong number of steps.

Two or more clues is the threshold for a positive result. Notice that the first two clues happen during the instructions, before you have taken a single step. The instruction phase is itself a scored part of the test.

What actually counts as each clue

Each clue has a precise definition in the NHTSA manual, and officers routinely score things that do not meet it. What the protocol actually requires:

• Cannot keep balance during instructions — the feet must actually break apart from the heel-to-toe stance. Swaying or using the arms while holding the stance is not a clue.
• Starts too soon — counts only if the officer actually told you not to start until instructed. Officers often leave that instruction out.
• Stops while walking — requires pausing for several seconds. Walking slowly is not a clue.
• Does not touch heel to toe — requires a gap of more than half an inch between heel and toe.
• Steps off the line — one foot has to come entirely off the line.
• Uses arms for balance — raising one or both arms more than six inches from the sides.
• Improper turn — actually removing the front foot from the line, or spinning or pivoting instead of taking a series of small steps.
• Incorrect number of steps — taking more or fewer than nine steps in either direction.

NHTSA attributes a 79 percent accuracy figure to the walk-and-turn, the share of subjects it claims an officer can correctly classify as at or above 0.08 using the two-clue threshold. That figure comes from validation studies where the test was scored as part of the full three-test battery, not in isolation, and where the average driver arrested had a BAC around 0.15.

The conditions the test requires, and rarely gets

The walk-and-turn was validated on a dry, level, hard, non-slippery surface. Real roadside conditions routinely fail that standard.

• The surface. Gravel, grass, cracked or uneven pavement, wet ground, or a highway shoulder with a drainage slope all make the heel-to-toe walk harder for reasons unrelated to alcohol. An officer who reports that a driver stepped off the line on a sloped shoulder is reporting a result the validation research does not support.
• The instructions and demonstration. The protocol includes specific standardized instructions and a required demonstration. An officer who shortens the instructions, skips the demonstration, or modifies the test is not administering the validated version.
• Footwear. Heels, boots, wedges, and sandals put a person at a mechanical disadvantage on a heel-to-toe line.
• Physical and medical conditions. The NHTSA research excluded people over 65, people with inner ear or back problems, and people more than 50 pounds overweight, so the accuracy figures were never established for those drivers.

The negative scoring system

Like the other standardized tests, the walk-and-turn uses a negative scoring system. You get no credit for what you do correctly. The officer counts only the things that go wrong. A person who walks the line nearly perfectly and raises an arm once for balance can be scored the same as someone who struggled the entire way. The test is not built to let you show you are sober. It is built to find clues that support an arrest.

How the walk-and-turn gets challenged

A serious defense does not argue in the abstract that the test is unreliable. It reviews the dashcam and bodycam video against the protocol and identifies what actually happened: whether the surface was level and dry, whether the officer gave the complete standardized instructions and the required demonstration, whether the officer began scoring during the instruction phase, whether your footwear or a physical condition was accounted for, and whether the clues the officer claims to have seen are even visible on the video.

Managing Partner Deandra Grant is a trained NHTSA SFST instructor who administers and grades these tests professionally, so she reviews the video with the eye of an examiner who knows exactly what proper administration looks like. Deviations that would be invisible to most attorneys become the basis for specific, grounded cross-examination a jury can follow. See how this fits the broader field sobriety tests and the HGN eye test.

Frequently Asked Questions

What is the walk-and-turn test?

It is a standardized field sobriety test where you take nine heel-to-toe steps along a line, turn, and take nine steps back while following the officer’s instructions. It is scored on eight clues, and two are enough to be marked a fail.

How many clues fail the walk-and-turn?

Two or more of the eight clues is the threshold for a positive result. Two of the clues, losing balance during instructions and starting too soon, can be scored before you take a single step.

Why do sober people fail the walk-and-turn?

The test was validated for a dry, level, hard surface and ideal conditions. An uneven or sloped surface, poor lighting, bad footwear, fatigue, anxiety, age, weight, and back or leg problems can all produce the same clues as alcohol.

Does the surface matter for the walk-and-turn?

Yes. It was validated on a dry, level, hard, non-slippery surface. A gravel shoulder, wet pavement, or a sloped roadway makes the heel-to-toe walk harder for reasons unrelated to drinking.

Can I refuse the walk-and-turn test?

Yes. Field sobriety tests are voluntary in Texas, and declining them carries no automatic license penalty, though the officer can still arrest you on other grounds. Learn more about refusing a DWI test.

How do you challenge a walk-and-turn result?

By reviewing the video against the protocol, the surface, the instructions and demonstration, the footwear, and any physical conditions, and showing where the administration deviated from the validated test.

What counts as stepping off the line on the walk-and-turn?

Under the NHTSA definition, one foot has to come entirely off the line. A heel that lands slightly to the side of an imaginary line, or a toe that drifts, does not meet the standard, yet officers frequently score it anyway.

How many instructions does the walk-and-turn have?

Researchers count 14 separate things you must remember and do at once, which is why NHTSA classifies it as a divided-attention test rather than a test of physical coordination.

Scored on the Walk-and-Turn After a Roadside Stop?

Two small clues on an uneven shoulder can become a DWI arrest. Deandra Grant Law is led by a certified SFST instructor who reviews the video against the protocol. Call (214) 225-7117 for a free, confidential consultation.