Field sobriety tests
The one leg stand test asks you to raise one foot about six inches off the ground, keep both legs straight, look at your raised foot and count out loud, “one thousand one, one thousand two, one thousand three,” until the officer tells you to stop. The officer times the test for 30 seconds and watches for four clues. Two clues is the decision point that federal training links to an alcohol concentration of 0.08 or more. In a North Carolina DWI case, those thirty seconds can carry real weight, so the instructions, the clock, the ground, your health and the video all deserve a close look.
What is the one leg stand test?
The one leg stand is one of the three standardized field sobriety tests (SFSTs) taught by the National Highway Traffic Safety Administration (NHTSA). It usually comes after the horizontal gaze nystagmus (HGN) eye test and the walk and turn. Like the walk and turn, it is a “divided attention” test. The idea is that alcohol makes it harder to do two things at once, so the test pairs a balance task (standing on one leg) with a mental task (counting out loud at a steady pace).
It is the shortest test in the battery. That is part of why officers like it, and part of why it deserves scrutiny. Thirty seconds leaves very little room for error, and one wobble on a sloped shoulder can be written up as a “clue.” For the full battery, see our guide to standardized field sobriety tests in North Carolina.
How NHTSA says the one leg stand should be given
NHTSA divides the test into two stages: an instructions stage and a balance-and-counting stage, and its manual warns that both stages “can affect the subject’s overall performance on the test.” Before the test begins, a careful officer asks about injuries, medical conditions and footwear, then explains and demonstrates the position and the count.
- Starting position
Stand with your feet together and your arms down at your sides. Do not start until the officer tells you to.
- Raise one foot
When told, raise either foot about six inches off the ground. Keep the raised foot parallel to the ground and keep both legs straight.
- Look at the foot and count
Keep your eyes on the raised foot and count out loud by thousands: “one thousand one, one thousand two, one thousand three…”
- Keep going until told to stop
If your foot touches down, NHTSA tells the officer to have you pick it back up and “continue counting from the point at which the foot touched.” The officer ends the test at 30 seconds.
NHTSA’s refresher manual also tells officers to observe “from a safe distance and minimize movement during the test so as not to interfere.” An officer who paces, shines a flashlight in your eyes or stands right beside you can affect your balance. If the video shows that, it matters.
Counting by thousands: why the officer controls the clock
The spoken count is the “divided attention” part of the test. It is not the timer. NHTSA training has the officer time the test, and the refresher manual says plainly: “If the subject counts very slowly, terminate the test after 30 seconds.” So reaching “one thousand thirty” does not end the test, and a slow count does not make it last longer.
Two practical points follow. First, counting too fast or too slow is not one of the four scoring clues. An officer may describe your count in the report, but it is not on the NHTSA scoresheet as a clue. Second, the timing itself can be checked. If the video shows the officer stopped at 15 or 20 seconds, never looked at a watch, or let the test run well past 30 seconds, it was not given the standardized way. Try the illustrative timer below to see how far your own mental count drifts from real seconds.
Try it: count to “one thousand thirty”
Press Start, count silently at what feels like one second per number, and press Stop when you reach “one thousand thirty.” This is an illustration only, not a test of anything.
The four clues and the two-clue decision point
The officer watches for four clues. NHTSA’s refresher manual states that “there is a maximum number of 4 clues on this test,” and that two or more clues indicates an alcohol concentration at or above 0.08.
| Clue | NHTSA training definition | Where scoring goes wrong |
|---|---|---|
| 1. Sways while balancing | Side-to-side or back-and-forth motion while holding the position. “Slight tremors of the foot or body should not be interpreted as swaying.” | Wind from passing trucks, sloped ground, darkness and the officer’s viewing angle make “sway” subjective. |
| 2. Uses arms to balance | Moves arms 6 or more inches from the side of the body to keep balance. | Hard to judge from several feet away at night. A reflexive arm movement on gravel is common. |
| 3. Hops | Keeps one foot off the ground but hops to maintain balance. | Uneven or loose surfaces, worn soles, boots or heels. |
| 4. Puts foot down | The raised foot touches the ground one or more times during the 30-second count. | Injury, weak ankle or knee, fatigue, or confusion about when the test ends. |
With only four clues possible, two is half the scoresheet. A brief arm lift plus one touch of the foot meets the decision point. Each clue counts once no matter how many times it happens, so a report that lists “swayed, used arms” may describe a single moment of wobbling. That is why the second-by-second video often matters more than the checkmarks.
Why 30 seconds? The timing behind the test
The test runs a full 30 seconds because NHTSA’s training says impaired people tend to fail late, not early. The refresher manual tells officers that “time is critical in this test” and that a person with an alcohol concentration above 0.10 “can maintain balance for up to 25 seconds, but seldom as long as 30.”
- 0 secYou raise your foot and start counting. The officer starts timing.
- 0–25 secNHTSA training expects that even some impaired drivers can hold the position through this window.
- 25 secNHTSA: a person above 0.10 “can maintain balance for up to 25 seconds, but seldom as long as 30.”
- 30 secThe officer ends the test, even if your count has not reached “one thousand thirty.”
That timing claim cuts both ways. If the video shows you held the position cleanly for the full 30 seconds, it undercuts an opinion of impairment based on this test. If the officer stopped early, started late or never checked the time, the test was not given the way it was validated.
How the one leg stand was validated, and its limits
NHTSA’s refresher manual reports that in the original Southern California Research Institute (SCRI) laboratory research, the one leg stand alone was 65% accurate. In the 1998 San Diego field validation study, it was 83% accurate at the 0.08 level. In that study, Jack Stuster and Marcelline Burns tested 297 motorists, and the manual reports that the three-test battery led to correct arrest decisions 91% of the time.
The manual also cites two other field studies of the full battery: 86% correct arrest-or-release decisions in Colorado (1995) and 95% correct arrest decisions in Florida (1997). Those are battery-wide figures, not one leg stand figures.
Several limits matter in court:
- Group accuracy is not individual proof. Even at 83%, the one leg stand misclassified roughly one in six people in the San Diego study. The figures describe how often clue counts matched measured alcohol levels in a study group, not whether one particular driver was impaired.
- It cannot measure alcohol. The test produces a clue count, nothing more. It cannot tell anyone whether you were at 0.05, 0.08 or 0.15.
- The research assumes standardized administration. The accuracy numbers come from tests given and scored the way the studies did it. A test given on a slope, timed loosely or scored with extra “clues” is not the test that was studied.
- Older drivers were barely studied. NHTSA notes that fewer than 1.5% of the subjects in the original studies were over 65.
A person commits impaired driving by driving a vehicle on a highway, street or public vehicular area (1) while under the influence of an impairing substance, (2) after having consumed enough alcohol to have an alcohol concentration of 0.08 or more at any relevant time after the driving, or (3) with any amount of a Schedule I controlled substance, or its metabolites, in the person’s blood or urine. A one leg stand score is offered as evidence on the first prong, being under the influence (appreciable impairment). It cannot measure an alcohol concentration or detect a drug.
Read G.S. 20-138.1 in our Chapter 20 libraryAge, weight, medical conditions and surfaces
Standing on one leg is a pure balance task, so anything that affects balance affects the score. NHTSA’s own materials acknowledge this.
Drivers 65 and older
In its walk and turn section, NHTSA’s refresher manual says the original research found that “individuals over 65 years of age or people with back, leg or inner ear problems had difficulty performing this test,” and that “less than 1.5% of the test subjects in the original studies were over 65 years of age.” The one leg stand is an even purer balance task, so the same caution applies. In other words, the studies say very little about how a sober 70-year-old performs. For an older driver, a clue count deserves extra caution.
Weight
Body weight changes where your center of gravity sits and how hard your ankle, knee and hip have to work to hold still on one leg for 30 seconds. NHTSA’s refresher manual does not give officers a weight cutoff, so if weight, conditioning or a recent injury played a role, it has to be shown with medical records and the video rather than assumed.
Medical conditions and medications
- Inner ear and vestibular problems. Vertigo, labyrinthitis, Ménière’s disease and recent ear infections all affect balance.
- Knees, hips, ankles and back. Joint replacements, arthritis, old sprains, sciatica and disc problems can make standing on either leg painful or unstable. See our ankle-injury case study.
- Neurological conditions. Neuropathy, prior concussions and similar conditions affect balance and coordination.
- Lawful medications. Some prescriptions affect balance, which raises separate questions about whether a drug was an “impairing substance.” See prescription medication and DWI.
Footwear and surfaces
NHTSA’s refresher manual says the walk and turn should be given, whenever possible, on “a reasonably dry, hard, level, non-slippery surface,” and that “individuals wearing heels more than 2 inches high should be given the opportunity to remove their shoes.” The one leg stand puts your whole weight on one foot, so those cautions apply with at least as much force. Boots, sandals and worn soles also change your base of support. At the roadside, gravel, grass, sloped driveways, wet pavement, cold, wind gusts from trucks and strobing blue lights all make balance harder.
Expect the State to point out that NHTSA’s manual says later field studies found “varying environmental conditions have not affected a subject’s ability to perform” the walk and turn. The answer is usually the video: a reviewer can see whether you were on a slope, whether the officer asked about injuries, and whether the “sway” is visible at all.
How the one leg stand is used in North Carolina DWI cases
In North Carolina, one leg stand results show up at three stages: the decision to arrest (probable cause), the suppression hearing, and trial. The officer usually describes the test as part of his observations, alongside the driving, odor, speech, admissions, the HGN and walk and turn, and any roadside portable breath test. Courts look at the totality of the circumstances, so the one leg stand rarely decides a case alone. A poor performance can help the State show probable cause. A clean performance can help defeat it.
Declining the test is different from refusing a chemical analysis under the implied-consent law, G.S. 20-16.2. Field sobriety tests are not chemical analyses, and declining them does not trigger the implied-consent refusal revocation. But North Carolina law lets the State tell the court you declined.
If a person charged with an implied-consent offense refuses to submit to a chemical analysis “or to perform field sobriety tests at the request of an officer,” evidence of that refusal is admissible in any criminal, civil or administrative action against the person.
Read G.S. 20-139.1 in our Chapter 20 libraryMiranda warnings are generally not required before the test. Physical performance is treated as non-testimonial evidence, and roadside questioning during an ordinary traffic stop is not custodial interrogation. Statements you make while performing the test can be a different matter, as the U.S. Supreme Court cases below explain.
North Carolina and U.S. Supreme Court decisions
These decisions show how courts actually treat one leg stand evidence. Each was checked against the opinion or a reliable summary. For more, browse our North Carolina DWI case law library.
The driver raised his foot more than six inches, stopped after fifteen seconds and put his foot down, then picked it back up and continued for at least fifteen more seconds when told to finish. He did the walk and turn without a problem. Despite a light odor of alcohol, a minor parking-lot collision that was not his fault and positive alco-sensor results, the Court of Appeals affirmed suppression because the officer lacked probable cause to arrest for impaired driving.
Read the opinion ↗On the one leg stand the driver “used his arms for balance and swayed.” With six HGN clues, missed walk-and-turn steps and other evidence, the Supreme Court held the facts were sufficient, as a matter of law, to support probable cause to arrest.
Read the opinion ↗At a checkpoint on Providence Road in Charlotte, the driver showed only one sign on the one leg stand, below the decision point, plus three HGN signs and two walk-and-turn signs, with odor, red eyes, an admission and two positive alco-sensor results. Probable cause existed. Passing one test does not end the inquiry.
Read the opinion ↗The district court noted that the officer’s HGN passes were shorter than NHTSA protocol and treated that as going to the weight of the results, not admissibility. The Supreme Court reversed suppression and found probable cause on the totality of the evidence. Expect the State to make the same “weight, not admissibility” argument about a mis-timed one leg stand.
Read the opinion ↗Physical dexterity tests are “not evidence of a testimonial or communicative nature,” so Miranda warnings were not required before them, even though the tests in that case were given after the arrest.
Read the UNC SOG summary ↗Slurred speech and lack of coordination observed during sobriety testing are physical, not testimonial, evidence. But a question calling for a testimonial answer (the “sixth birthday” question) asked in custody without warnings had to be suppressed.
Read the opinion ↗The driver could not complete a roadside “balancing test” without falling. The Court held that ordinary roadside questioning during a traffic stop is not custodial interrogation, but once a driver is in custody, Miranda applies even to misdemeanor traffic offenses.
Read the opinion ↗Read together, these cases show the pattern. The one leg stand is rarely decisive by itself. A clean or near-clean performance helps, as in Overocker. A poor performance adds to the State’s case, as in Parisi. And procedural departures are usually argued as weight rather than automatic exclusion, so the defense has to show why the departure matters. Our case notes on Overocker, Parisi and Townsend go further.
Reviewing the one leg stand on video
Because the test is so short, dashcam and body-camera video can be replayed second by second. We review the evidence against the NHTSA standard and the officer’s report, looking for these points:
- Did the officer ask about injuries, medical conditions and footwear first?
- Was the surface dry, hard, level and non-slippery?
- Did the officer explain and demonstrate the position and the count?
- Which leg did you raise, and did an injury affect that side?
- Did the officer actually time the test, and for how long?
- At what second did any foot-down, hop or arm movement happen?
- Were your arms really 6 or more inches from your body?
- Is the “sway” visible on video, or only in the report?
- Did the officer stand back and stay still, or move around you?
- Were headlights, strobes, wind or traffic in play?
In district court, G.S. 20-38.6 generally requires motions to suppress or dismiss to be made before trial, so this review has to happen early. If a blood warrant followed the arrest, note that in State v. Rogers (N.C. Oct. 17, 2025) the Supreme Court of North Carolina overruled State v. Carter and recognized a good-faith exception to any exclusionary rule under Article I, Section 20 of the state constitution. Older articles that say North Carolina has no good-faith exception are out of date. See the UNC School of Government’s analysis.
What to do after a one leg stand test
Document your health and the scene, protect the video, and keep the test in perspective. It is one piece of a larger case that has its own DMV deadlines.
- Write down the scene: surface, slope, lighting, weather, traffic, and what the officer said and demonstrated.
- Gather medical proof: records of joint, back, ear or neurological problems, a list of medications, and your height and weight.
- Keep your shoes and photograph them.
- Ask about preserving video early. Dashcam and body-camera footage is kept only for set retention periods.
- Deal with the license issues: a chemical-test refusal or a 0.08+ result generally triggers a 30-day civil revocation and possible limited driving privilege questions.
- Bring it all to your consultation. See how to prepare.
Quiz: how well do you know the one leg stand?
How many clues does NHTSA treat as the decision point on the one leg stand?
- One
- Two
- Four
There are four possible clues, and two or more is the decision point in NHTSA training.
A driver counts slowly and only reaches “one thousand twenty” when 30 seconds have passed. What should happen?
- The test continues until the driver reaches thirty
- The slow count is scored as a clue
- The officer ends the test at 30 seconds
NHTSA’s manual says, “If the subject counts very slowly, terminate the test after 30 seconds.” Counting pace is not one of the four clues.
What share of subjects in the original SFST research were over 65?
- Less than 1.5%
- About 10%
- About 25%
NHTSA notes that fewer than 1.5% of the original test subjects were over 65.
In State v. Overocker, what did the Court of Appeals decide?
- One foot-down always means probable cause
- The officer lacked probable cause, so suppression was affirmed
- Field sobriety tests are inadmissible in North Carolina
The driver did the walk and turn without a problem and finished the one leg stand when told to. On those facts, the court affirmed suppression for lack of probable cause.
Thirty seconds on one leg is not a measure of your alcohol level. It is a balance task, and anything that affects balance belongs in the analysis.Adkins & Purkey
From our book
Charged with DWI in North Carolina?
Our book explains the one leg stand and the rest of the roadside battery from both sides: how officers are trained to give and score it, and the medical, environmental and procedural questions defense lawyers raise. It is written for drivers and families.
Related guides
Top 10 FAQs: the One Leg Stand test
What is the one leg stand test?
It is one of NHTSA’s three standardized field sobriety tests. You stand with your feet together, raise one foot about six inches off the ground with both legs straight, look at the raised foot, and count out loud by thousands while the officer times you for 30 seconds.
What are the four clues on the one leg stand?
Swaying while balancing, using arms to balance (moving them 6 or more inches from the side of the body), hopping, and putting the foot down. NHTSA says slight tremors should not be scored as swaying.
How many clues count as failing?
NHTSA training treats two or more of the four clues as the decision point indicating an alcohol concentration at or above 0.08. “Fail” is not a legal finding; it is one piece of evidence the court weighs with everything else.
How long does the test last, and who keeps time?
The officer times the test for 30 seconds. NHTSA’s manual says that if the subject counts very slowly, the officer should end the test after 30 seconds, so your count does not control when it stops.
Why do officers make you count “one thousand one”?
The count is the mental half of a divided-attention test: you must balance and count at the same time. Counting too fast or too slow is not one of the four scoring clues.
How accurate is the one leg stand test?
NHTSA’s manual reports 65% accuracy for the one leg stand alone in the original laboratory research and 83% at the 0.08 level in the 1998 San Diego field study of 297 motorists. Those are study-group figures, not proof that any one driver was impaired.
Does age or weight affect the one leg stand?
They can. NHTSA’s refresher manual says the original research found people over 65 or with back, leg or inner-ear problems had difficulty with the walk and turn, and that less than 1.5% of the original subjects were over 65. The one leg stand is a purer balance task. Weight is not an NHTSA cutoff, but it affects balance and should be documented.
Can an injury, medical condition or the ground affect the results?
Yes. Back, leg and inner-ear problems, neuropathy and some medications affect balance. For the walk and turn, NHTSA calls for a reasonably dry, hard, level, non-slippery surface when possible and says people in heels over 2 inches should be offered the chance to remove them; a one-leg balance test is at least as sensitive to the ground and shoes.
Do I have to take the one leg stand in North Carolina?
Declining field sobriety tests is not a chemical-test refusal under the implied-consent law, so it does not trigger that revocation. But G.S. 20-139.1(f) makes evidence that you refused to perform field sobriety tests at an officer’s request admissible against you.
Does the officer have to read Miranda rights before the test?
Generally no. State v. Flannery held that physical dexterity tests are not testimonial, and Berkemer v. McCarty held that ordinary roadside questioning is not custodial interrogation. Under Pennsylvania v. Muniz, testimonial questions asked in custody without warnings can still be suppressed.
Adkins & Purkey, PLLC
Talk to a North Carolina DWI lawyer
If your report says you “failed” the one leg stand, we can check the timing, the clues, the surface and your medical history against the video and the NHTSA standard. Offices in Huntersville (Lake Norman) and Locust (Stanly County), serving Charlotte, Mecklenburg, Iredell, Cabarrus, Stanly and courts across North Carolina.
General North Carolina legal information as of November 2026, not legal advice for any specific case. Reading this article does not create an attorney-client relationship. Past results and study figures do not predict the outcome of any case. Attorney advertising.
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