The National Highway Traffic Safety Administration (NHTSA) developed standardized field tests to help police officers evaluate drivers who appear intoxicated or impaired. Field sobriety tests are often inaccurate, with many false-positive results.

Learn more about the underlying problems with field sobriety tests and your rights if asked to perform one.

Types of Field Sobriety Tests

An officer who pulls you over and suspects you’ve been drinking could ask you to step out of the car and perform a field sobriety test. The three standard NHTSA tests are:

  • The Horizontal Gaze Nystagmus Test: Informally known as “follow the object with your eyes,” this test allegedly determines intoxication based on eye movements.
  • The Walk and Turn Test: Officers give you directions to evaluate your ability to perform appropriate physical and mental tasks.
  • The One-Leg Stand Test: This test supposedly reveals if your balance has been affected by drugs or alcohol.

Non-Standard Sobriety Tests

Some officers include field sobriety tests in place of the standard NHTSA methods. These often include:

  • The Finger-to-Nose Test: Standing with your head back, eyes closed, and touching the nose tip with the index finger.
  • The Alphabet Test: Reciting all or part of the alphabet, forwards or backward.
  • The Finger Count Test: Counting while touching each finger on one hand and then the other.

Why Field Sobriety Tests Have Unreliable Results

Field sobriety tests are highly subjective. Police officers lack the medical training to fully understand that people have balance issues and different responses to visual tests.

There are no specific standards to administer these tests. Police officers usually fail to consider physical, medical, emotional, and environmental factors that cause unreliable or inaccurate results.

Medical Conditions

According to the Mayo Clinic, numerous medical conditions affect an individual’s balance. Being unable to perform a field sobriety test when you have Parkinson’s Disease, ear infection, or even a migraine does not mean you’re intoxicated.

An experienced DUI defense attorney can challenge a field sobriety test using medical documentation such as a written diagnosis, examination notes, or a doctor’s testimony.

Being Overweight

Significantly overweight individuals have difficulty standing on one leg. Morbidly obese individuals sometimes cannot walk even a very short distance.


Many people age 65 and older have issues maintaining their balance. They often use a cane or walker to keep themselves from falling.

Uneven Surface

Trying to stand on one leg on an uneven surface would be challenging. This task is more complicated if the ground is sandy or slippery. Women wearing high heels might find it impossible to walk and turn without losing their shoes, which could be interpreted as intoxication.

Weather & Lighting

Poor lighting, rain, extreme cold or warm temperatures contribute to the unreliability of these tests. Even the proximity to traffic rushing by affects the test’s outcome.

Stress & Anxiety

Being pulled over by the police is stressful, even for sober, law-abiding citizens. Many people find it difficult to concentrate on these tests under the glare of a suspicious police officer.

Presumption of Guilt

Despite your right to be presumed innocent until proven otherwise, some police officers have made up their minds that you’re a drunk driver, no matter how you perform on a field sobriety test.

You Can Refuse a Field Sobriety Test

There is no Pennsylvania law compelling you to submit to a field sobriety test. Officers cannot arrest you for refusing to take one, but they could use a failed test against you. It is riskier to agree to a field sobriety test than to refuse.

Probable Cause

Failing a field sobriety test opens the door to potential arrest on a DUI charge based on probable cause. Police do not have probable cause if you refuse a field sobriety test.

There are other influencing factors for probable cause, such as red eyes, the odor of alcohol, or belligerent behavior. However, these alone wouldn’t be enough to justify an arrest without a field sobriety test.

Chemical Test

Police officers have the right to ask you to take a chemical test. Pennsylvania law requires drivers to consent to a chemical DUI test. Refusing a breath, blood, or urine test usually leads to an arrest and an automatic suspension of your driving privileges for at least one year.

Get Help from a Pennsylvania DUI Attorney

Field sobriety tests aren’t legally required, but some officers try to scare motorists into complying with them. If a field sobriety test resulted in a DUI charge, you deserve a strong legal advocate on your side.

Award-winning attorney Michael J. Skinner aggressively fights for his clients and is ready to help you. Call the Skinner Law Firm at 610-436-1410 or reach out online to schedule a free, no-risk consultation.

Article Author

Michael J. Skinner, the founder of Skinner Law Firm LLC, is a former prosecutor with the Chester County District Attorney’s Office.

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