Field Sobriety Test: One-Legged Stand

The one-leg stand (OLS) is the third of the three standardized field sobriety tests, used alongside the walk-and-turn and the HGN eye test. The officer asks you to balance on one foot and count, and then judges your performance. Like the others, it is built to be hard and graded on the officer's opinion. I am Joel Brand, and here is how the one-leg stand works, why it is so easy to fail while completely sober, and how I challenge it.

How the test is administered

You are told to stand with one foot raised about six inches off the ground, keep that leg straight, point your toe, look down at your foot, hold your arms at your sides, and count out loud in a specific way ("one thousand one, one thousand two...") until the officer tells you to stop, usually around 30 seconds. It is a divided-attention test of balance, instruction-following, and your sense of time, all at once, in an unnatural position most people never practice.

The four clues

The officer is watching for just four clues: swaying while balancing, using your arms to balance, hopping to keep your balance, and putting your raised foot down. Exhibiting two of those four is scored as a failure. With only four possible clues over a full 30 seconds of standing on one leg, the margin for a sober person is almost nonexistent. Put your foot down once and raise your arms once, and you have "failed."

Why 30 seconds is longer than it sounds

Most people badly underestimate how hard it is to balance on one leg for half a minute, sober and at rest, let alone on a roadside. Try it right now on a flat floor in good light with no one watching. Many sober, healthy adults sway, raise an arm, or set the foot down at least once. Now add the real conditions of a DUI stop, where the officer is also requiring you to keep your leg straight, point your toe, stare at your foot, and count out loud in a prescribed cadence. Each of those extra demands pulls attention away from the one thing that is actually being graded, your balance. The test is engineered so that ordinary, innocent movements become "clues."

Why sober people fail

Balancing on one leg for half a minute is genuinely difficult for many sober adults, and it gets dramatically harder under the conditions of a DUI stop. NHTSA acknowledges that age, weight, and inner-ear or leg, knee, hip, and back conditions all impair performance regardless of alcohol. Add a sloped, gravelly, or wet surface, poor lighting, cold, wind, fatigue, anxiety, and the wrong footwear, and you have a recipe for a sober person to wobble. The test essentially asks people to perform like gymnasts on the shoulder of a highway at night. And because the foot only has to touch down once and the arms only have to come up once to score two of the four failing clues, the window between a "pass" and a "fail" can come down to a single, perfectly normal balance correction that any sober person would make.

Medical and physical conditions that mimic impairment

The one-leg stand punishes any condition that affects balance, and there are many. Inner-ear problems and vertigo make single-leg balance nearly impossible. Prior knee, hip, ankle, and back injuries, arthritis, neuropathy from diabetes, obesity, and simply being older than 65 all degrade performance. So does ordinary fatigue at the end of a long day. NHTSA's own guidance flags several of these groups as people who should not be expected to do the test normally even when sober. Officers rarely ask whether any of them apply before they start grading. I take a careful history of your physical condition, because it frequently explains the "clues" the officer wrote down. See medical conditions that can affect a DUI.

Officer administration and bias

As with every standardized test, the one-leg stand is only valid when administered correctly, and it frequently is not. Officers misstate the instructions, mis-time the 30 seconds, choose a poor surface, and score normal balance corrections as clues. And the officer almost always already suspects impairment before the test starts, which shapes how each small sway gets written down. The body-camera footage often tells a very different story than the report.

What the footage reveals

The video is usually the most important evidence in a one-leg stand case. Reports describe dramatic swaying and hopping; the footage often shows a person standing on one leg in the dark, on uneven ground, making the small corrections any sober person would make. The report may claim the officer counted a full 30 seconds when the video shows far less, or that the surface was level when it plainly was not. I obtain every available second of dash-cam and body-cam video and lay it next to the officer's written account. Those discrepancies are exactly what creates reasonable doubt at trial.

How I challenge the one-leg stand

I obtain the video and compare it against the report and the NHTSA protocol, then cross-examine the officer on the surface and lighting, the timing, your physical condition and footwear, and every departure from the standardized method. The objective is to show the "clues" reflect the test and the conditions rather than alcohol, which in turn undermines the probable cause for the arrest. It works best in combination with challenges to the walk-and-turn and HGN tests, and the overall unfair field sobriety test defense. It also supports the broader argument about the most common police mistakes at a DUI stop. See my top DUI defenses.

It was probably voluntary

For drivers 21 and over, the one-leg stand is generally optional, unlike the mandatory post-arrest chemical test. Most officers do not volunteer that distinction, and many people balance on one leg in the dark for a test they were free to decline.

Failed the one-leg stand? Let's look at the video.

A failed one-leg stand is not proof you were drunk, and the footage often proves it. Use the free case analysis on this page, or call me directly at (888) 271-6644. I answer my own phone, 24/7.