Understanding Standard Field Sobriety Tests

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    The Standardized Field Sobriety Test (SFST) includes three separate tests. They are typically administered after a person has been pulled over on suspicion of driving under the influence of alcohol (DUI). The purpose of the tests is to reveal clues that a police officer can use to determine whether the driver of the vehicle is in fact intoxicated.

    The tests were developed by the National Highway Traffic Safety Administration (NHTSA) and the Southern California Research Institute.

    The three separate tests that make up the SFST are:

    • The Horizontal Gaze Nystagmus (HGN) test. This measures nystagmus, an involuntary movement of the eye that is exaggerated under the influence of alcohol. During the test, the officer slowly moves an object like a pen or flashlight, which the test subject must follow with his or her eyes.
    • The Walk and Turn (WAT) test. This creates “divided attention” by asking the subject to listen to and follow directions while taking nine steps, heel to toe, along a straight line. Then the subject is asked to turn and walk back the same way. The officer looks for indicators like losing balance, using arms to balance, stepping off the line, or failing to walk heel-to-toe.
    • The One-Leg Stand (OLS) test. In this test, the officer instructs the test subject to stand with one foot raised about six inches off the ground. The subject may also be asked to do another task, like counting aloud, while standing on one foot. The officer times the subject for 30 seconds while looking for indicators that the suspect is intoxicated.

    At Mushkatel, Gobbato, & Kile, P.L.L.C., our experienced Surprise, Scottsdale, Sun City, Peoria, and Glendale, Arizona DUI defense attorneys strive to provide outstanding representation to every client we defend. To learn more, contact us today at (480) 467-3434 for a free and confidential case evaluation.

    Visit Our Sun City Drunk Driving Offense Law Offices

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    About the Author

    Zachary Mushkatel

    Zachary Mushkatel discovered his affinity for the law by chance. As a political science major at the University of Arizona, he first aspired to become a professor. But an unexpected invitation to participate on a mock trial team at the university encouraged him to turn his competitive spirit and drive…