Field sobriety test inaccuracy rates

Like most people in Missouri, you have probably heard people talk about the field sobriety tests that may be used when a driver is suspected of being impaired. However, you may not fully understand what these tests are or how inaccurate they may really be. This can be important to anyone who has been charged with driving while intoxicated as they need to learn their defense options.

As explained by, the National Highway Traffic Safety Administration has standardized and authorized three different tests for use by law enforcement officers. Each of these tests has a known inaccuracy rate. The least accurate of all three tests requires a person to balance on one leg while counting aloud at an officer’s direction. The mere use of the arms to assist with balance may contribute to a failure of this test. The accuracy rate of this test is 65 percent.

The walk-and-turn test requires a person to walk in a specific manner and take a certain number of steps without deviating from the designated path. This test has an accuracy rate of 68 percent. The final test evaluates a normal and involuntary jerking motion in the eye. This is the most accurate of all three tests with a rating of 77 percent. 

If you would like to learn more about the types of tests administered during a drunk driving investigation and how the results of these tests may be used against you, please feel free to visit the field sobriety test page of our Missouri drunk driving defense website.


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