In the walk-and-turn test, you stand heel-to-toe on a line while the officer gives instructions, then take nine heel-to-toe steps, turn in a prescribed way, and take nine steps back. The officer scores eight specific clues, and under the National Highway Traffic Safety Administration's (NHTSA) training, two are enough to count against you. This page describes the test as the 2023 NHTSA manual teaches it. It is part of our Montana DUI Guide.
Why It Is Called a Divided Attention Test
NHTSA's manual describes the walk-and-turn as a test that requires a person "to divide attention among mental tasks and physical tasks." The mental tasks are understanding spoken instructions, processing information, and recalling it. The physical tasks are balance and coordination while standing still, walking, and turning.
The manual also sets a standard for what makes such a test fair. It must be "reasonably simple for the average person to complete as instructed when sober," and "tests that are difficult for a sober subject to perform have little or no evidentiary value."
The Instruction Stage
The officer is trained to give these instructions, with demonstrations:
- Place your left foot on the line (real or imaginary).
- Place your right foot on the line ahead of the left, with the heel of the right foot against the toe of the left.
- Place your arms down at your sides.
- Maintain this position until the instructions are complete. Do not start to walk until told to do so.
- The officer asks whether you understand so far.
This stage is scored. You are being asked to hold an awkward stance while listening. Two of the eight clues come from here.
The Walking Stage
The officer then explains and demonstrates the rest:
- Take nine heel-to-toe steps on the line, turn, and take nine heel-to-toe steps back.
- On the turn, keep the front foot on the line and turn by taking a series of small steps with the other foot.
- Keep your arms at your sides, watch your feet at all times, and count your steps out loud.
- Once you start walking, do not stop until you have completed the test.
- The officer asks whether you understand, then tells you to begin.
If a person does not count out loud or watch their feet, the manual tells the officer to remind them. Neither of those is one of the eight scored clues.
The Eight Scored Clues
| Clue | How the manual defines it |
|---|---|
| Cannot keep balance while listening to the instructions | The feet must actually break apart or step off the line. Swaying or using the arms while holding the stance is not this clue. |
| Starts too soon | The person begins walking before being told to. |
| Stops while walking | Not recorded if the person is merely walking slowly. |
| Does not touch heel-to-toe | A gap of one-half inch or more between heel and toe on any step. |
| Steps off the line | One foot entirely off the line. |
| Uses arms to balance | Raises one or both arms six or more inches from the sides. |
| Improper turn | Removes the front foot from the line while turning, spins or pivots, or loses balance while turning. |
| Incorrect number of steps | More or fewer than nine steps in either direction. |
The manual states that if a person exhibits two or more clues or cannot complete the test, the officer should classify the alcohol concentration as at or above 0.08, and that using this criterion officers will accurately classify 79% of subjects. It cites a 1998 field study for that figure. The same manual reports that NHTSA's analysis of the original laboratory data found the walk-and-turn, by itself, 68% accurate.
Those definitions are precise for a reason. A report that says "used arms for balance" means, under the manual, arms raised six inches or more. A report that says "missed heel-to-toe" means a gap of at least half an inch. Video often lets those claims be measured.
Conditions That Affect the Test
- Surface. "Whenever possible," the test should be conducted on a reasonably dry, hard, level, non-slippery surface with enough room for nine heel-to-toe steps. The original research recommended that if those conditions were not present, the person be asked to perform the test elsewhere or that only the eye test be given. The manual adds that later field studies indicated varying environmental conditions did not affect performance, and that standardizing the test for every road condition is unrealistic.
- Age and physical condition. The original studies suggested that people over 65 or with back, leg, or inner ear problems had difficulty. The manual notes that fewer than 1.5% of the original test subjects were over 65.
- Footwear. People wearing heels more than 2 inches high should be given the opportunity to remove their shoes.
- Repetition. If a person has difficulty, the officer should continue from that point, not from the beginning, because the test "may lose its sensitivity if it is repeated several times."
- Distraction. The officer is told to observe from a safe distance and limit movement that may distract the subject.
Western Montana adds its own conditions: gravel shoulders, crowned county roads, ice, wind, and winter boots. None of those appear in a score sheet unless the officer writes them down.
What the Manual Says About Its Own Limits
Two statements in the manual are worth quoting. First, "the SFSTs are a tool to assist you in seeing visible signs of impairment and are not a pass/fail test." Second, the validation "applies only when the tests are administered in the prescribed and standardized manner, the standardized clues are used to assess the subject's performance, and the standardized criteria are employed to interpret that performance. If any one of the SFST elements is changed, the validity may be compromised."
That second statement is the foundation of most cross-examination about roadside tests. It is NHTSA, not a defense lawyer, saying that departures from the protocol matter.
How It Is Used in a Montana Case
Before an arrest, the walk-and-turn is one of the things an officer relies on for probable cause. At trial, it is evidence of impairment that the officer describes to the judge or jury. Under MCA § 61-8-1018(1)(c), a report of a physical or psychomotor assessment is admissible if it was made by a person trained by the Department of Justice or with training the Department recognizes. Montana treats field sobriety tests as a search that requires particularized suspicion (Hulse v. State, 1998 MT 108, ¶ 38).
The test matters most when there is no number, or a low one, and the charge rests on impairment. For the battery as a whole, see our field sobriety tests page. For the other two tests, see the HGN eye test and the one-leg stand. For how the results are contested, see challenging field sobriety tests, and for whether you must take them at all, can I refuse field sobriety tests.
This page describes NHTSA's published training materials (2023 curriculum) and explains Montana law in general as of October 9, 2026. It is not legal advice about your specific case.