DUI/DWI Field Sobriety Tests: How to Challenge Them

How you do on a field sobriety test (FST) is a key part of evidence when you’re pulled over for DUI/DWI. The police use this roadside testing to determine if a driver is under the influence of alcohol or drugs. While the prosecution may want to use an FST to prove guilt, a DUI defense attorney can challenge the evidence to seek a more favorable resolution to your DUI case.

Schedule a Free Initial Consultation Today!

What Is Field Sobriety Testing?

Police officials use both standardized and non-standardized field sobriety tests to assess a driver’s level of intoxication. They are taught to look for clues, such as poor focus, problems completing tasks, and poor coordination when giving the tests.

A DUI defense lawyer reviews the accuracy, validity, and dependability of the testing.

Types of Standard Field Sobriety Tests (SFSTs)

The National Highway Traffic Safety Administration (NHTSA) validates the three standard field sobriety tests that are given to determine DUI/DWI.

These tests include:

1. Horizontal Gaze Nystagmus (HGN): During this test, the police officer looks at the suspect’s eyes while they follow an object moving horizontally across their field of vision. The object is either a flashlight or a pen. Alcohol may cause an involuntary jerking of the eyes, also called nystagmus.
2. Walk-and-Turn (WAT): Suspects are told to take nine steps, walking heel-to-toe, moving forward in a straight line. The suspect turns on one foot and returns in the same manner.
3. One-Leg Stand (OLS): During this test, the suspect stands on one leg, lifting the leg about six inches from the ground to a 30-second count.

Dependability of the Testing

The SFSTs are considered the most dependable because they have been scientifically validated. According to NHTSA studies:

• HGN is 77 percent accurate in detecting BAC (Blood Alcohol Content) of over or less than  0.10 percent.
• WAT is 68 percent accurate.
• OLS is 65 percent accurate.

When all three tests are combined, their accuracy in identifying a BAC of 0.08 percent or higher (the legal limit in most U.S. states) is around 91 percent.

Non-Standard Field Sobriety Tests

The following tests may be used when a suspect is stopped for DUI/DWI. 

However, the assessments are not validated by the NHTSA.

• Finger-to-Nose: Touch the tip of the nose with the index finger.
• Alphabet Test: Recite the alphabet or a portion of it.
• Counting Test: Count backward from a given number.
• Romberg Balance Test: Stand with feet together, head back, and eyes closed.
• Finger Count: Touch each finger to the thumb while counting.
• Hand Pat: Alternately pat the back of one hand with the palm of the other.

Non-standard tests are less reliable because they haven’t undergone the same rigorous scientific validation as the standard tests. They may be influenced by factors like nervousness, physical condition, or language barriers the suspect may have.

Because field sobriety testing is not infallible, other evidence should also be considered in DUI/DWI cases. That’s why it’s important to contact a DUI defense lawyer. They can review all the factors of your case and how the test administration may lead to different results – or a reduced charge or dismissal.

Reasonable Suspicion: Why Did Police Ask for an FST?

A police officer must have a reasonable suspicion of impairment to pull over a driver for DUI/DWI. This suspicion might include erratic driving, slurred speech, watery and red eyes, or the odor of alcohol.

If a DUI defense lawyer can argue that the officer did not have probable cause, they can file a motion to suppress the evidence. The motion can be used to dismiss or reduce the DUI charge.

Medical Conditions that Can Affect FST Results

Some common medical issues that can influence how you do on an FST include:

• High or low blood sugar
• Drowsiness
• Diabetes
• A general illness
• Problems with balance or vertigo
• Back pain
• Knee pain
• A physical injury

Reviewing the Testing Conditions and the Suspect’s Condition

A DUI defense lawyer may challenge an FST by asking the following questions about the environment and the physical condition or coordination of the suspect:

• Was the road level or sloped?
• Was it slick or windy at the time?
• Does the suspect naturally have poor coordination or ataxia?
• Was the suspect limping – maybe due to a physical injury or pain?
• Was the lighting sufficient?
• Does the suspect have vision problems, or do they wear contact lenses?
• Did the suspects’ age, weight, or physical or mental condition affect their test results?
• Was the suspect over-anxious or nervous?
• Was the driver overly tired?
• Was the driver taking prescription medicine at the time of the test?

Some people naturally have nystagmus.

Challenging the Administration of the FST

Your attorney might argue that the police officer did not explain the test clearly enough. They may also question the officer’s qualifications concerning training and certification. For example, an attorney may check to see if the officer’s certification is current.

In addition, a lawyer may challenge the test interpretation. They might ask if the officer properly scored and interpreted the results.

As you can see, your attorney can review the evidence gathered from an FST and challenge the results in one of various ways.

If you’re asked to perform an FST, stay calm and cooperative. Doing so will help your attorney better prove inconsistencies at a later date. They can do this by examining video evidence as well as reviewing your age, medical history, and overall physical condition.

Contact a DUI Defense Attorney Today

Did the police arrest you for DUI/DWI? Do you want to know the next step? If so, it’s best to contact a DUI defense lawyer to discuss your case. They can navigate the legal process and defend you with the confidence their experience brings. Call and set up a legal consultation ASAP. Call a New York State criminal defense lawyer today.