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How do field sobriety tests work?

On Behalf of | Feb 20, 2019 | dui

When someone is pulled over by police in Atlantic City due to an officer suspecting the driver is under the influence of drugs or alcohol, there are certain steps the officer takes to determine the driver’s level of impairment. One of these steps is field sobriety testing. There are three individual sobriety tests that make up the Standard Field Sobriety Test. When properly administered, this assessment has been found to be quite accurate in determining one’s balance, coordination and other abilities.

The first part of the Standard Field Sobriety Test is the horizontal gaze nystagmus test. This assesses the involuntary jerking of one’s eyeball. The officer holds an item such as a pen about 12 inches in front of the person’s face and asks the individual to follow the movement of the pen with his or her eyes while the officer moves the pen left and right. The officer observes how distinct the jerking of the person’s eyeballs is and at what angle the jerking begins.

The second test is the walk-and-turn test. During this test the officer observes as the driver takes nine heel-to-toe steps, turns, and takes nine more heel-to-toe steps back the opposite direction. The officer observes if the driver walks in a straight line, places his or her feet correctly, takes the correct number of steps, has difficulty balancing and listens to the entire set of instructions. Failure to do any of these correctly can indicate impairment.

The final part of the Standard Field Sobriety Test is the one-leg stand test. During this test the driver is asked to stand with one foot raised about six inches off the ground while counting. The officer observes if the driver counts incorrectly or has difficulty balancing.

While these tests are considered reliable indicators of impairment by Atlantic City police, they are not always accurate. There are a number of reasons someone who is not under the influence of drugs or alcohol may fail one or more of these sobriety tests. These include medical conditions, injuries and disabilities, among others. Also, the tests are only considered accurate when properly administered, so incorrect instruction can yield a false result.  A knowledgeable defense attorney can help a driver determine why he or she may have failed a sobriety test when not actually impaired.