Pennsylvania drivers stopped by law enforcement officers and eventually suspected of driving under the influence of alcohol may commonly be asked to participate in a series of tests before their blood alcohol content is measured via any chemical means. These initial activities, field sobriety tests, theoretically provide support to officers that a person may be impaired. This information allows them to legally place a person under arrest and charge them with a drunk driving offense.

As explained by AAA, the results of any field sobriety test cannot be considered completely accurate in all cases. One of the tests, the horizontal gaze nystagmus test, evaluates an involuntary jerking motion of the eyeball. This motion becomes more pronounced in people who have consumed alcohol. However, some medical eye or neurological conditions may also produce an exacerbated action similar to that in a person who has had an alcoholic beverage.

The other tests evaluate a driver’s ability to balance perfectly, and to follow and execute multiple instructions simultaneously. Hearing loss may prevent a driver from fully understanding the instructions. Physical problems with knees, feet or hips may impede a person’s ability to balance while still or while walking along a straight line. Officers should ask drivers if they have any such conditions and notate the information in their reports.

This information is not intended to provide legal advice but is instead meant to help Pennsylvania residents better understand what field sobriety tests are used for and what factors may prevent a person from being able to pass one or more of these tests.