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What Are the Field Sobriety Tests?

When the police pull someone over for suspicion of DUI, the officer will ask the driver several questions, such as, “Have you been drinking” or “How much have you had to drink”? Even if you admit to drinking, the officer can only request that you perform field sobriety tests if there is evidence of intoxication, such as:

• A strong smell of alcohol on the person’s breath or clothing
• The person is slurring their words while speaking
• The driver cannot find his or her driver’s license, vehicle registration or proof of insurance
• Bloodshot or watery eyes
• Empty containers, such as beer cans or bottles of alcohol

The officer may ask the driver to complete several different field sobriety tests to determine the level of intoxication. Failing the field sobriety tests gives the officer probable cause to request a blood, breath or urine test.

Standardized Field Sobriety Tests
The National Highway Transportation Safety Administration (NHTSA) has issued a standardized model for field sobriety tests, which include:

• Horizontal Gaze Nystagmus Test (officer is looking for an involuntary jerking of the pupil)
• Walk and Turn Test (heel to toe, take nine steps in a straight line, make a military pivot and come back)
• One-Legged Stand Test (stand on one leg, arms at side for up to 30 seconds)

Accuracy of Standardized Field Sobriety Tests
According to the NHTSA, the laboratory test data determined that:

• The Horizontal Gaze Nystagmus test is 77 percent accurate
• The Walk and Turn Test is 68 percent accurate
• The One-Legged Stand Test is 65 percent accurate
• The Horizontal Gaze Nystagmus and Walk and Turn Test together are 80 percent accurate

Non-Standardized Field Sobriety Tests
Not all states or local law enforcement agencies follow the standardized model, and they may conduct alternative tests, which include:

• Rhomberg balance test (feet together, head back and eyes closed for 30 seconds)
• Finger-to-nose test
• Finger-to-thumb test
• Recite a portion of the alphabet
• Count backwards

A criminal defense attorney may call the validity of these non-standardized tests into question.