The one-leg stand test is one of three standardized field sobriety tests (FST) that police use to determine whether a motorist was driving while impaired. Generally, police consider it useful a tool to detect intoxication, but less reliable than the horizontal gaze nystagmus field sobriety test.
(According to the National Highway Traffic Safety Administration (NHTSA), the three standardized FSTs are reliable tools for investigating whether a driver has a blood alcohol concentration (BAC) of .1% or more.)
Like the walk-and-turn test (another standardized FST), the one-leg stand is intended to test a driver's ability to complete a task requiring divided attention. The theory is that someone who’s drunk will be less coordinated and able to focus on directions—and perform more poorly—than someone who's not.
How is the One-Leg-Stand Test Administered?
First, the officer should test the driver on a reasonably dry, hard, level, and non-slippery surface. If the driver is wearing shoes with heels more than two inches high, the officer is supposed to ask the driver to remove them.
Next, the officer gives the instructions. The instructions are usually something like:
- "Stand with your feet together and arms down to your sides."
- "Don't start the test until I instruct you to do so."
- "When I say to start, raise one leg approximately six inches off the ground, foot pointed out."
- "Keep both legs straight with your arms at your side."
- "While staying in that position, count out loud in the following manner: ‘one thousand and one, one thousand and two, one thousand and three,’ until I tell you to stop."
- "Keep your arms by your sides at all times and keep watching your raised foot."
When giving these instructions, the officer is supposed to demonstrate each part and ask if the driver understands. And while the driver performs the test, the officer should avoid making movements that could distract the driver.
What are the One-Leg Stand Clues?
The officer looks for several "clues" of intoxication while giving the instructions and observing the driver balance on one foot. There are a total of four clues. Under the NHTSA guidelines, if the officer observes two or more clues, the driver most likely has a BAC of .1% or higher.
Any of the following counts as a clue:
- swaying while balancing
- moving an arm more than six inches from the side of the body to maintain balance
- hopping to maintain balance, and
- putting a foot down at least once.
If the officer observes the same clue more than once, it should count only as one clue. If the motorist can't do the test at all or puts a foot down more than three times, the officer is supposed to record it as four clues.
Get in Touch with an Experienced Attorney
DUI law is complicated and differs by state. If you’ve been arrested, talk to a DUI attorney in your area. An experienced local DUI attorney can tell you what the law is in your state and, in consideration of the facts of your case, if you have any defenses.