You may have wondered what really happens when a person who has been pulled over by police is suspected of drunk driving. One of the things officers generally do is request that the driver complete certain tasks. Known as field sobriety tests, these tasks are part of a standard drunk driving investigation. 

FieldSobrietyTests.org indicates that there are three such tests standardized for use by the National Highway Traffic Safety Administration. The goal of the tests is to provide support for arresting a person, not to conclusively prove that they are actually drunk. The test with the highest accuracy rate, which is still only 77 percent, measures an involuntary jerking of a person’s eyeball. The remaining two tests each evaluate a person’s ability to process more than one action at a time.

In the walk and turn test, a driver must balance, walk in a specific manner, count and follow directions. This test is said to be 68-percent accurate. The one leg stand test also evaluates balance while the person holds the other foot in the air in front of them and counts in thousands out loud. The accuracy rate of this test is 65 percent. Weight, muscle and joint problems are just some of the things that may interfere with a person’s ability to pass these tests. 

If you would like to learn more about the three tests used by law enforcement before making the decision to arrest someone for suspected drunk driving, please visit the standardized field sobriety testing page of our Illinois DUI and criminal defense website.