The Controversy Over Roadside Field Sobriety Tests

Copyright 2006 Lance Knowlton

Roadside field sobriety tests (FSTs), developed at the behest of the National Highway Traffic Safety Administration (NHTSA), are commonly employed by police officers during DUI stops to determine whether a driver is under the influence of alcohol.

FSTs generally consist of a battery of three to five exercises, such as walking and turning in a different direction, standing on one leg, nystagmus (using the eyes to track an object), touching the finger to the nose and reciting the alphabet.

The officer may subjectively decide whether the individual failed the test, or he may decide after applying recently-promulgated federal scoring standards. The NHTSA thinks these tests are a reliable way to gauge sobriety; however, there is mounting evidence that they are anything but.

Many FSTs are based on the concept of divided attention, which occurs when an individual must concentrate on more than one thing at the same time. A driver must divide her attention among various physical and mental activities to safely operate a vehicle, and her ability to do so is significantly reduced by the consumption of alcohol.

Ideally, FSTs evaluate the same mental and physical capabilities that a person needs to drive: information processing; short-term memory; judgment and decision making; steadiness, sure reactions; clear vision; small muscle control; and coordination of the limbs.

The most recently developed of the FSTs is the horizontal gaze nystagmus (HGN) test. HGN does not test a driver