Accuracy of field sobriety tests challenged

Many police officers across the country use the field sobriety test as a way to determine intoxication. However, these tests are not always accurate.

With the holiday season on its way, law enforcement agencies in Illinois may be making extra efforts to catch drunk drivers. One of the tools police officers use before a drunk driving arrest is the field sobriety test. This test is usually conducted during a traffic stop when an officer suspects the driver is intoxicated.

What is a field sobriety test?

The Standardized Field Sobriety Test, states the National Highway Traffic Safety Administration, consists of a battery of three different tests. After being pulled over by an officer, a driver may be asked to perform the following actions:

• Looking into a flashlight for the horizontal gaze nystagmus test, which gauges the movements of a driver's eyes

• Walking in a straight line, then turning back and walking in the opposite direction during the walk-and-turn test

• Standing on one foot and counting for 30 seconds without putting the other foot down during the one-leg stand

Certain actions, such as losing one's balance, holding the arms out to balance or failing to follow instructions may lead an officer to suspect the driver has been drinking.

How accurate are field sobriety tests?

According to NBC 29 News, each of these tests is far from accurate. The horizontal gaze nystagmus, for example, is reportedly only 77 percent accurate. Respectively, the walk-and-turn and one-leg stand tests are 68 percent and 65 percent accurate. This leaves a great deal of room for error when a passing or failing grade on a field sobriety test is left to the discretion of a police officer.

In an experiment involving three volunteers from a shopping mall who had not been drinking, each person reported having difficulty passing a field sobriety test. Two had difficulty balancing, and one said she didn't follow the directions accurately because she was sleep-deprived. They expressed concern that the test would be even more difficult during a real traffic stop when they felt nervous or under pressure.

How can a sober person fail a field sobriety test?

There is nothing to worry about for a driver who has had nothing to drink, right? Not according to ABC Action News. People who have balancing difficulties may find a field sobriety test challenging. Some may have physical impairments, cognitive disabilities or injuries that can affect walking or understanding instructions. Police officers may suspect that a driver's red eyes due to fatigue are a result of intoxication, or that a speech impediment means he or she has had too much to drink.

Many believe that field sobriety tests are designed to fail. After a drunk driving arrest, it is important to contact an Illinois DUI defense attorney.