Accuracy level of field sobriety tests not encouraging

Field sobriety tests are not 100 percent accurate, and may result in false positives for sober drivers.

With the holiday season approaching, law enforcement in California is likely to take extra measures to catch drunk drivers before they get into accidents. One of the most common ways for police officers to screen for drunk driving is the field sobriety test. Rather than the proof of intoxication that may be provided by a breath test device or a chemical test, field sobriety tests rely on a police officer's judgment as to whether or not the driver has been drinking. Naturally, one may question the reliability of such a test.

What is a field sobriety test?

The Standardized Field Sobriety Test, according to the National Highway Traffic Safety Administration, involves a battery of three different roadside tests that law enforcement gives a suspected drunk driver. They are meant to help a police officer recognize certain telltale signs of intoxication. These tests include the following:

• The horizontal gaze nystagmus test, in which an officer looks at the involuntary jerking of a subject's eyes, which may be pronounced after drinking.

• The walk-and-turn, during which the driver is asked to walk in a straight line and then turn around and walk back without losing his or her balance.

• The one-leg stand, during which the driver is supposed to stand on one foot and count for 30 seconds.

These tests measure a subject's balance, coordination and ability to follow directions, as well as other factors. However, some claim that field sobriety tests are set up to make people fail, sober or otherwise. A false positive during a field sobriety test may result in a sober person being charged with a crime.

Experiment suggests common inaccuracies

In an experiment given to three volunteers outside a shopping center, the sober people were asked to perform field sobriety tests. NBC 29 News reported that one woman failed to properly follow instructions during the walk-and-turn because she claimed she was sleep-deprived. Another had difficulty balancing during the one-leg stand despite saying he had good balance. The third volunteer also had trouble with balancing during the tests. They reported concern about whether they would be able to pass a field sobriety test during a traffic stop in which they were nervous or stressed out.

Field sobriety tests may be less accurate if a person has a condition that makes the test more difficult, states ABC Action News. For example, if a person has a medical condition that causes slurred speech, has red eyes from allergies or an injury or illness that affects walking or balancing, an officer may suspect intoxication.

The accuracy of field sobriety tests may also be concerning to California residents. The horizontal gaze nystagmus test is said to be just 77 percent accurate, while the walk-and-turn and one-leg stand tests are only 68 percent and 65 percent accurate, respectively. An experienced drunk driving defense attorney may be able to help after an arrest based on failing a field sobriety test.