What are the ways a sober person can fail a field sobriety test?

Police officers rely on their judgment in a field sobriety test to determine if a driver is intoxicated. These tests, however, are not always accurate.

During the upcoming holiday season, it would not be unusual for Minnesota residents to see an increase in law enforcement officers on the patrol for drunk drivers. Field sobriety tests are one of the most common tools officers use when trying to get intoxicated drivers off the road. Just how accurate are field sobriety tests? Some studies have shown that they may not be as reliable as people might think.

Defining a typical field sobriety test

According to the National Highway Traffic Safety Administration, police officers conduct a battery of standardized tests in a roadside field sobriety test. A driver may be evaluated on the following:

  • How well he or she performs in the walk-and-turn test, which consists of the person walking in a straight line and turning on foot to walk back in the same direction
  • Whether he or she is able to balance on one foot in the one-leg stand and count out loud for up to 30 seconds
  • If the eyes show a pronounced jerking movement during the horizontal gaze nystagmus test, which is common among those who are intoxicated

A police officer may consider other factors, such as the smell of the driver's breath, the redness of the eyes and his or her speech and behavior. Field sobriety tests do not rely on the chemical composition of a driver's blood or breath, but rather on an officer's individual judgment. Therefore, a person who has not had anything to drink may end up facing false intoxication charges after "failing" a field sobriety test.

How is it possible for a sober person to fail the test?

Completely sober people, states ABC Action News, may find the standard field sobriety test difficult to pass under numerous conditions. They may have an injury or medical condition that affects walking and movement. They could have an inner ear condition or a cognitive impairment that affects balance. They might have a speech impediment, red eyes due to fatigue or stress or another condition that mimics the signs of intoxication. They might, in fact, be merely nervous or afraid and fail the test on those conditions alone.

NBC 29 News reported on the results of an experiment given to three sober volunteers at a shopping center. Each person performed a field sobriety test. They each passed, but all said they found parts of the test difficult. Two subjects had difficulty balancing and the third said she had trouble following directions because she was sleep-deprived. They all agreed that the test would be harder to pass during a real traffic stop.

The National Highway Traffic Safety Administration claims that the horizontal gaze nystagmus test is only 77 percent accurate, the walk-and-turn only 68 percent and the one-leg stand only 65 percent accurate. These scores would result in the officers getting a "D" or an "F" on any test they took in high school! These figures may show how it can be difficult to "pass" a field sobriety test, and how easy it is to get accused of drunk driving. They also illustrate why it is best to refuse to participate in these so-called "tests" at all. Those facing DUI charges after failing a field sobriety test should get in touch with a Minnesota drunk driving defense attorney to protect their rights.