The one-leg stand test is a test used to investigate potential DUI suspects. The officer asks the suspect to hold one foot off the ground about six inches, while counting slowly to 30. If the suspect sways, hops, uses their arms to balance or cannot keep their foot up, they may be considered intoxicated.
Law enforcement officers use many field sobriety tests (FSTs) to try to tell whether a driver is impaired or not. One of the three “standardized” FSTs is the one-leg stand test. This test is considered reliable because it has been tested repeatedly both in labs and in the field. When properly administered, it has a 65% accuracy rate and can help officers make a decision on whether to arrest you for DUI.
The other two “standardized” FSTs are:
- The horizontal gaze nystagmus test (HGN), and
- The walk and turn test
All three of these tests are admissible as evidence in court, but the one-leg stand test is the least reliable of the three.
Why is the one-leg stand test used?
The one-leg stand test is more than a test of balance. It is meant to measure how well you can divide your attention on two simple things at once (the physical act of balancing, and the process of counting off thirty seconds). It also shows officers whether you can follow instructions. An intoxicated person has trouble with all three of these things.
How is the one-leg stand test done?
To do the one-leg stand test the officer will first find a level, clear, dry patch of ground for you to stand on. They will then demonstrate the position and explain what they want you to do. The starting position for the test is to stand with the feet together and the hands at the side. The officer will then give you the instructions:
- When the officer tells you to, you will lift one foot off the ground about six inches
- You should look down at that foot the whole time, which makes balancing easier
- You will keep your arms at your sides and not use them to balance
- Once in this position, you should count quickly from 1,001 to 1,030: “One thousand one, one thousand two, one thousand three…” etc. This will approximate 30 seconds.
If you count slowly, the officer may ask you to stop after 30 seconds has passed, regardless of what number you’re on.
How do officers decide whether I passed or failed the test?
During the test, the officer will then look for four things:
- Are you able to stand without swaying from side to side?
- Are you able to balance without moving your hands more than 6 inches from your sides to help you?
- Are you able to stay on one leg without hopping?
- Are you able to complete the entire 30 seconds without putting your foot down even once?
If you cannot do any one of these four things, it counts as a “point,” and each point on the test counts against you. This means you could end up with as many as 4 points total, but it only takes 2 points to fail the test. You can also fail if you have to set your foot down three or more times during the test, regardless of your actual point total.
If you fail, officers will assume you have a blood alcohol concentration (BAC) of .10% or more, which is higher than the legal limit for driving in California.
Is failing the one-leg stand test enough to convict me of DUI?
Not really. The court does consider the one-leg stand scientific, and allows it to be used as evidence against you. But it’s hardly full proof. There are many reasons why a sober person might fail a one-leg stand test, and it is very rare for this test to be the main evidence in the prosecution’s case. Generally, they will use a breath test or blood test as their key piece of evidence. But if officers are claiming you failed a one-leg stand test, it’s important to attack its validity.
How do I attack the one-leg stand test as evidence in my DUI case?
One-leg stand tests have two major weaknesses:
- Even if police administer the test correctly, it’s only about 65% accurate. That means that more than a third of people who fail the test are actually sober.
- There are many ways for law enforcement to do the test incorrectly, whether because of poor training, not following procedures, or not having ideal testing conditions on the side of the road.
Either or both of these weaknesses could affect the validity of the one-leg stand test in your case, and you can challenge it. Some of the grounds for challenging the one-leg stand test include:
- You are over 60 years of age. Balance declines as people grow older.
- You are more than 50 pounds overweight, which affects physical performance on this kind of test.
- You have any physical condition that might affect your ability to stand on one leg, such as arthritis; leg, back or foot problems; or inner ear problems.
- You suffer from brain damage, or may have had a brain injury in the accident.
- You have a mental disorder that affects your ability to concentrate or follow instructions.
- The surface where the officer conducted the test was sloped, cracked, uneven, had gravel or litter, was wet or was slippery.
- It was too dark for you to easily see your foot when you looked down.
- You were wearing unsuitable footwear, such as heels, and/or were not given the chance to remove your shoes for the test.
- You had tight pants, very baggy pants, or other clothing that interfered with your test.
- The officer had his weapon toward you or was otherwise making you nervous during the test.
- The officer did not demonstrate the position or give clear instructions.
- The officer moved around or distracted you during the test, or other distractions were present.
- The officer did not time the test to make sure that it was really 30 seconds.
Any of these factors can invalidate the one-leg stand test in your case. A good lawyer can often fight a DUI successfully regardless of the field sobriety test results.
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