Walk and Turn Test

Police officers use certain voluntary cognitive and physical tests to determine if drivers are intoxicated. The tests varied in the past: a driver might be asked to touch a finger to the nose, recite part of the alphabet, or walk a straight line.

In 1982 the National Highway Traffic and Safety Administration (NHTSA) created standardized field sobriety tests that fairly reliably determine a driver’s intoxication level. These tests range from 65-80 percent reliable in establishing that a driver is under the influence of drugs or alcohol. Officers are trained to administer these tests safely and reliably.

These tests provide an officer with probable cause to arrest the driver on suspicion of DUI. After arrest, the driver can be given a breath test roadside or is taken to a detention facility to undergo urine or blood testing to determine the blood-alcohol content (BAC).

One of the standardized field sobriety tests is called ‘walk-and-turn.’ The driver walks heel-to-toe along a line for nine steps. Turning at the end and returning completes this simple test that any sober person should be able to perform. The driver is tested on the ability to understand simple directions (cognitive testing) and physically managing the test.

The police officer watches to see if the driver loses balance, overbalances, sways, or does not take the requested number of steps. As in the one-leg stand test, the test should be given in adequate lighting on level, dry ground. If these conditions cannot be met, the officer attempts to move to a better area for the test or uses the results of the horizontal gaze nystagmus (HGN) test alone, as the one-leg stand test requires the same optimal conditions as the walk-and-turn test. Officers are aware that the elderly and overweight might have difficulty with these when sober and take that into account.

The NHTSA studies indicated that 65 percent of those who fail two or more of these steps will have a BAC of .10 percent or greater or are under the influence of drugs. While a driver may politely refuse to take standardized field sobriety tests, this in itself permits the officer to arrest the driver for probable cause. In most states the driver’s license is immediately suspended or revoked for refusing to take this test. Repercussions can be more severe for refusing to take the test than if the driver took the test and failed.