If you or someone that you know has been arrested and charged with a drunk driving offense, field sobriety tests may have been used during the arrest process. It is important that defendants understand the purpose of these tests and just how accurate – or not – they really are.

Many people incorrectly assume that field sobriety tests are one way that an officer can tell if a person is intoxicated. As explained by FieldSobrietyTests.org, these roadside tests are in no way able to or even designed to do this. Instead, their purpose is to give just enough support to the theory that a person might be drunk so that a police officer may legally place the driver under arrest.

There are three tests used at the location of a drunk driving stop but none of them are completely accurate. Their individual accuracy rates range from 65 percent for the walk and turn test to 77 percent for the eye gaze test. The one-leg stand test is 68-percent accurate. The combined accuracy rate if all three tests are administered is slightly higher at 82 percent but still leaves quite a margin for error. This may be one area of opportunity for drivers when it comes time to defend themselves against a drunk driving charge. 

This information is not intended to provide legal advice but is instead meant to give residents in North Carolina an overview of what field sobriety tests are able to evaluate, why they are used and what their true accuracy rates are.