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Field Sobriety Tests

Philadelphia Field Sobriety Tests

Field Sobriety Tests (Fsts) are psychophysical tests used by police officers to make a preliminary determination as to whether an individual is under the influence of alcohol. These tests are designed to divide the individual's attention amongst multiple activities which are difficult to perform if intoxicated. In theory, an officer using these tests will be able to observe certain behaviors and visual cues of intoxication if the individual is in fact intoxicated.

These tests are not highly effective, though. And through careful video observation of the tests, a knowledgeable attorney may be able to call the Fsts into question in order to either contest a DUI or use as leverage in dealing with a prosecutor.

Understanding the Tests

Among the field sobriety tests used by officers in Pennsylvania, there are three which are typically used by police officers: The One-Legged Stand (OLS), The Walk and Turn (WAT), and The Horizontal Gaze Nystagmus (HGN). These tests are designed to allow the officer to observe an individual's movements, balance, coordination, and listening comprehension in order to make a determination as to potential intoxication.

The Horizontal Gaze Nystagmus: The individual is instructed to observe the motion of either a pen or penlight, without moving their head, as they move it from side to side and up and down slightly above eye level and 12 to 15 inches from the individual's face.

What HGN tests: Whether there is a nystagmus within the eyes. The nystagmus is the involuntary jump of the eye which often occurs within intoxicated individuals. It is a result of diminished reflexes causing the individual to lack smooth pursuit.

The Walk and Turn: The individual is required to take nine steps, heel to toe, arms at their side, walking in a straight line, and pivot, returning the way they came while counting their steps aloud throughout the test.

What WAT tests: This test is used primarily to observe balance. The heel to toe aspect with arms at the side measures an individual's balance as they either sway or raise their arms if intoxicated.

The One-Legged Stand: The individual is instructed by the officer to stand on one leg of their choice, lift the other foot approximately six inches off the ground, and count until the officer tells them to stop.

What OLS tests: Like the WAT, this test checks the individual's balance. The idea is that in the normal 30 second test period that an intoxicated individual will lose balance in their arms or legs, causing them to sway, hop, or place their raised foot on the ground.

Problems With Field Sobriety Tests

There are a number of problems with these tests:

Accuracy - The accuracy of these tests, even under perfect conditions, is suspect. Some studies have found them reasonably reliable while other studies have found HGN to be only 77% effective, while the OLS is only 65% effective. And this is assuming perfect conditions!

Conditions - The conditions in which the tests are performed are almost never perfect. These tests are designed to be performed on flat surfaces, without environmental factors, and with people of average condition. This is a problem because sides of roads and streets are typically at some angle and paved with rocky surfaces. Additionally, those wearing boots or heels will naturally have difficulty performing these tests and though afforded the option of removing their foot-wear they will then often be stepping on rocky surfaces or debris, hindering their abilities. Weather is an uncontrollable factor in that rain, wind, cold, etc. will all affect an individual's ability to be attentive and perform the tests. Finally, people who have physical ailments, are overweight, or are older may simply be unable to perform these tests under any circumstances.

Officers - Another variable is officer instruction. Does the officer give appropriate and clear instructions? Is the officer loud enough for the individual to hear? Officer instruction is very important as incorrect instructions can cause a person to fail the test no matter other circumstances and unintelligible instructions will have the same effect.

Why Do I Need a Lawyer?

You need somebody who understands these tests and their application who can review the facts of your case and make the appropriate arguments to a prosecutor or, if necessary, a judge. Usually a completely sober individual will not be charged with a DUI, so it is likely that many of the facts will not be in your favor. In this case it is essential you retain a knowledgeable DUI attorney to review these field sobriety tests and fight on your behalf.

This content was written on behalf of Greg Prosmushkin.

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