Updated on October 12th, 2023 at 08:43 pm
There are several misconceptions regarding standardized field sobriety tests in Wisconsin. The media portrays a 
drunk driver having to walk a straight line, touch the tip of his nose, and say the alphabet backwards.
According to the National Highway Traffic Safety Administration, law enforcement agencies must perform three standardized field tests during the pre-screening process of detecting evidence of impairment by a drunk driver.
Some Non-Standardized Field Sobriety Tests may be used. The One-Leg Stand Test, the Walk-and-Turn Test, and the Horizontal Gaze Nystagmus test are three of the most accurate that law enforcement agencies use to reveal signs of intoxication.
Field sobriety testing
Horizontal gaze nystagmus test
The Horizontal Gaze Nystagmus (HGN) test is designed to check for involuntary jerking of the eyes in suspected impaired drivers. During this test, the officer will hold a stimulus like a pen about a foot away from the person and ask them to follow the stimulus with their eyes.
The following are the three signs an officer will look for as evidence of impairment:
- Lack of Smooth Pursuit – The officer will look to determine whether the eyes move smoothly or if the eyes are jerking when following the stimulus.
- Distinct and Sustained Nystagmus at Maximum Deviation – When a person’s eye reaches maximum deviation, the eye will jerk involuntarily, even in an unimpaired person. This slight jerkiness is slight and may not even be seen by the naked eye. However, a person who is impaired will have a more pronounced jerking in his/her eyes and will last for a longer duration.
- The onset of Natural Nystagmus Prior to 45 Degrees – A person whose eyes begin jerking prior to reaching a 45-degree angle is more likely to be impaired. The earlier the onset of nystagmus, the more impaired the driver likely is.
The police officer looks for these clues in each eye, for a total of six (6) clues. When an officer notes 4 of 6 clues, it is evident that a person is impaired.
Although the horizontal gaze nystagmus can be a result of being under the influence of alcohol or drugs, atmospheric and medical conditions can also affect performance on FSTs. These include:
- Barometric pressure
- Fluctuations in barometric pressure
- Bacterial or viral infections
- Eye disease
- Vitamin deficiencies
- Sunstroke
- Glaucoma
- Inner ear conditions
- Neurological disorders like epilepsy and multiple sclerosis
- Endocrine conditions, including diabetes mellitus and thyroid disease
- Cardiovascular disease
- Innocuous substances like aspirin, nicotine, and caffeine
- Some prescription medication
Walk and turn test
The Walk and Turn (WAT) Test is typically the second test an officer will administer when determining signs of alcohol impairment. It’s simply a divided attention task where law enforcement officers require drivers to concentrate on multiple things simultaneously, usually mental and physical activities.
This test is given in two phases. The first phase is the instruction stage. The police officer will ask the driver to stand in the starting position while giving verbal instructions and demonstrating.
The second phase is the walking stage, in which the driver must walk nine (9) steps on a line (real or imaginary), turn as instructed, and walk nine (9) steps back to the starting position. There are eight (8) indicators of impairment an officer will look for during both phases of this test:
- Whether the driver maintains balance during the instructions
- The driver begins the test before being instructed to instruction
- Stops while walking
- The steps are not heel-to-toe
- Steps off the line
- Uses arms for balance
- Does not turn properly
- Incorrect number of steps
The total number of cues law enforcement officers need to observe, to “prove” drug or alcohol impairment is 2 of 8.
One leg stand test
The One Leg Stand Test is typically the final standardized field sobriety test that an officer will administer to someone they suspect of being under the influence of alcohol.
I say typically because there are a variety of other exercises that an officer may have you perform, such as saying the ABCs or touching your finger to your nose. Other tests similar to these are not standardized and have little bearing on your arrest. An experienced Wisconsin DUI Attorney like Nathan J. Dineen will know how to defend against non-standardized tests.
The one-leg-stand test (OLS) has two phases:
- The instructional phase
- The performance phase
In order for the test to conform to NHTSA standards, it must be conducted on a surface that is reasonably level, dry, hard, and non-slippery.
The officer will instruct the driver to stand with their feet together and arms at their side. When the officer instructs the driver to begin the test, the driver will raise their foot 6 inches above the ground while keeping the leg straight and the foot parallel to the ground.
The driver is instructed to count aloud from 1-30 in a one-thousand format (i.e., one one-thousand, two one-thousand, etc.). The officer will look for four (4) signs of alcohol impairment:
- Swaying
- Using arms for balance
- Hopping
- Putting your foot on the ground
An officer needs 2 of 4 clues as evidence of intoxication.
Interpreting the results of the one-leg stand
An individual has a 65 percent chance of having a BAC of over 0.10 percent if he or she does any two of four things during the test. The first is using arms to balance. The second is hopping instead of standing still. The third is swaying back to front or side to side while balancing. The last is putting down the foot that is supposed to be held up.
Potential problems with the one-leg stand
People who have health problems that affect balance (such as back, leg, or middle ear issues), are 65 years of age or over, or who are obese or overweight by at least fifty pounds can have difficulty with this test regardless of alcohol impairment or lack thereof.
Additionally, test subjects wearing footwear with heels two or more inches in height should be offered the chance to remove them before the test.
How accurate is field sobriety testing?
The National Highway Traffic Safety Administration (NHTSA) claims that the three tests have standardized procedures and accurately predict Blood Alcohol levels of about 0.10+% 65-77% of the time. Specifically, they claim the accuracy of field sobriety tests to investigate evidence of intoxication as follows:
- HGN – 77%
- OLS – 54%
- WAT – 68%
Do officers usually administer field sobriety tests correctly?
No, and a driver’s performance on field sobriety tests is going to be a significant part of any DUI arrest. You must have an attorney that understands standardized field sobriety testing, how the tests are administered, and how they are evaluated.
Nate Dineen is certified in Standardized Field Sobriety Test Administration. He observes and evaluates field sobriety test administration every day.
If you are serious about fighting your Wisconsin DUI charge, you need knowledge and experience on your side. You need an attorney that focuses specifically on Wisconsin OWI Defense.
Can you refuse field sobriety tests in wisconsin?
You are not required by law to take a breathalyzer or perform field sobriety tests when you’re pulled over for an OWI investigation. However, if you refuse, you can still be arrested even if you pass the field sobriety tests, but the officer still suspects you are under the influence. Once arrested, you will be required to submit to chemical tests due to Wisconsin’s implied content law.
Experienced wisconsin field sobriety test attorney
Did you fail the Wisconsin field sobriety test?
Have you been arrested for Wisconsin DUI or OWI?
If so, contact Nathan J. Dineen. Nate focuses his practice on DUI Defense and has years of experience challenging OWI arrests based on standard field sobriety test results. You may not have passed the tests for multiple reasons, and we know how to challenge them for reasonable doubt.
We invite you to call our office for a free consultation to help determine your best course of action. You shouldn’t let a field sobriety test rob you of your right to drive in Wisconsin.