Field Sobriety Tests: Introduction and History

For decades, police officers have used certain voluntary tests to determine possible intoxication of drivers stopped on suspicion. The tests varied widely: a driver might be asked to touch his or her finger to the nose, stand on one leg, or walk a straight line. No studies were available to determine the fairness of these tests.

The National Highway Traffic and Safety Administration (NHTSA) researched these tests in 1977 and 1981 and provided a sound battery of tests that could fairly reliably determine a driver’s intoxication level.

These simple tests are only to give an officer just cause – called ‘probable cause’ – to arrest the driver on suspicion of DUI. On average, these tests range from 65-80 percent reliable in establishing that a driver is in fact under the influence of drugs or alcohol.