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Field Sobriety Tests

When a person is suspicious of drunk driving, police officers will ask the individual to perform a series of tests. The tests are used to determine a person’s blood alcohol content.

The three most common field sobriety tests are:

The Horizontal Gaze Nystagmust test

The Walk and Turn Test

The One Legged Stand Test

Unfortunately, none of these three sobriety tests are 100% accurate. Sometimes officers use faulty equipment or untrained officers perform the tests incorrectly resulting in a bad test score. People who are disabled or experience heath problems tend to have more difficulty performing these routine sobriety tests.

Lets take a look at these three field sobriety tests.

The Horizontal Gaze Nystagmus Test

The Horizontal Gaze Nystagmus Test (HGN) is known to be the most reliable of the three tests at 77% accuracy.
Nystagmus is the involuntary eye movement that causes jerking or trembling. It is a lack of smooth pursuit. If the driver’s eyes tend to jerk before reaching 45 degrees, this tells the officer that the blood alcohol content is above 0.05%
The standard ways of conducting the Horizontal Gaze Nystagmus test is by holding an object, such as a light or a pen, 12-15 inches away from the driver’s face and slowly move the object from side to side.  A trained police officer will try to observe any slight signs of involuntary movement that can be categorized as Nystagmus.

But alcohol is not the only reason why a person might show signs of Nystagmus. Medications, drug prescriptions, neurological disorders, head trauma, and excessive amounts of nicotine or caffeine can cause signs of Nystagmus.

The Walk and Turn Test

The walk and turn test is also used by officers to determine if a person is above the alcohol legal limit.

This test must be conducted on a dry, flat, non slippery surface area that is in no danger to the person walking. The officer will advise the driver to complete nine heel-to-toe steps on a visible line or walk parallel to a curb. The officer will stand back and observe for any improper turning, walking offline, incorrect number of steps, heels and toes not touching, and non following directions.

The problem with this test is that many sober people have trouble completing this task. Physical disabilities, over weight and bad weather conditions can obscure the end results.

One Legged Stand Test

The One Legged Stand test is the least reliable of the three.

As well as the walk and turn test, this test must be conducted on a dry, level, non slippery surface. The officer instructs the driver to raise one foot while counting out loud for thirty seconds or less. From a few feet away, the officer observes for any clues of intoxication such as the swaying of the arms, balancing, unable to maintain posture, and hopping on one foot.

There are a few factors that can cause a sober person to fail this test. People with disabilities, old of age, and over weight cannot complete this test. Bad weather conditions can also have an impact in the results.

What can you do?

If you or someone you know is arrested for a DUI, immediately contact an experienced DUI attorney to help investigate your case and defend you.
At the Law Offices of James V. Bickford, IV, our team of expert DUI attorneys will meticulously investigate your case and aggressively fight to defend you in court. We will use our experience and skills to help you through your case.