Field Sobriety Tests

Challenging Roadside Tests

The Standardized Field Sobriety Tests (SFST) is a combination of three specific tests which are administered roadside by a police officer. This battery of tests is used by law enforcement to give them probable cause to make a DUI arrest. These standardized tests were initially developed in response to research that was sponsored by the National Highway Traffic Safety Administration (NHTSA); the research itself was conducted by the Southern California Research Institute.

Subsequently, a formal training program was developed, and this training is available today through the NHTSA to assist law enforcement personnel in becoming more proficient at detecting DUI suspects, describing their intoxicated behavior, and presenting more reliable and effective testimony when they are in court. The International Chiefs of Police (IACP) is responsible for providing the formal administration and accreditation of the program.

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Horizontal Gaze Nystagmus (HGN)

Horizontal Gaze Nystagmus refers to the involuntary jerking of the eye that occurs normally as the eyes gaze to one side. When a person is not intoxicated, nystagmus occurs when the eyes are rotated at a high peripheral angle. When someone is impaired by alcohol, the nystagmus is more exaggerated and can occur more easily, even at lesser angles. Also, when someone is impaired by alcohol, they're known to have more difficulty tracking a moving object.

With the HGN test, the police officer asks the suspect to follow a moving object such as a pen or a flashlight. While doing this, the officer watches the suspect's eyes as they track the moving object. With this test, the officer will look to see if the eyes can follow the moving object smoothly and they will look at the jerking of the eyes. The HGN test may also indicate if the person has consumed inhalants, barbiturates, and other depressants.

Walk and Turn

The Walk-and-Turn test is a divided attention test. This test requires the suspect to both listen and follow instructions while performing physical movements. With the Walk-and-Turn test, the suspect is told to take nine steps, heel-to-toe, along a straight line.

After they have taken the nine steps, the suspect is directed to turn on one foot and walk back in the same manner, in the opposite direction. The police officer will be looking at the person's balance while listening to directions. The officer will be looking to see if the person loses their balance, or if they can't touch heel-to-toe, or if they step off the line, or if they have to use their arms to balance etc.

One Leg Stand

The One-Leg Stand test is also a divided attention test. With this test the suspect is told to stand on one foot approximately six inches raised from the ground and to count aloud (one thousand one, one thousand two and so on) until they are instructed to put their foot down. The police officer is supposed to time the suspect for a period of 30 seconds. The police officer will be looking to see if the suspect hops to maintain balance, or if they put their foot down, or if they sway, or if they have to use their arms for balance.

These tests are used by law enforcement to gain probable cause to make an arrest; therefore, any evidence collected on the police officer's dash cam can be used as evidence against you in order to secure a DUI conviction. These tests are frequently inaccurate and inconclusive and the officer's opinion about how you perform these tests is subjective.

Please note that while there is no penalty for "politely" refusing to perform the field sobriety tests, if you fail to submit to a chemical test in the form of a breath, blood or urine test, then under California's "Implied Consent" law, you will be subject to an automatic driver's license suspension.