Field Sobriety Tests

An experienced lawyer is your best defense.

If a police officer suspects you are driving under the influence of alcohol or drugs and pulls you over, he or she may decide to administer a Standardized Field Sobriety Test (SFST). The SFST is a series of three tests developed based on research conducted by the National Highway Traffic Safety Administration (NHTSA) and the Southern California Research Institute. Police receive formal training in administering these tests. These tests are administered systematically and evaluated according to measured responses of the suspect. The three tests of the SFST are:

• the horizontal gaze nystagmus (HGN)
• the walk-and-turn
• the one-leg stand

Your Rights and the Field Sobriety Test
Under Michigan law you have the right to refuse the SFST, which can be difficult to pass even for some nondrinking drivers. Also, depending on the police officer’s level of training, the test results may be skewed. There is no penalty for refusing to take these roadside tests. By refusing the SFST, you are denying the prosecution possible evidence if you subsequently are charged.

If you do take the SFST and are concerned about the results, it is important you have a DUI attorney with Edward Duke’s skill and experience review every aspect of how the test was administered and its results. His more than 30 years of experience successfully defending against DUI / OWI charges make him one of the most knowledgeable DUI attorneys in Michigan.

HGN Testing
Horizontal gaze nystagmus is an involuntary jerking of the eyeball which occurs naturally as the eyes gaze to the side. However, when a person is impaired by alcohol, nystagmus is exaggerated and will often have difficulty smoothly tracking a moving object. In the HGN test, the officer observes the eyes of a suspect as they follow a slowly moving object such as a pen. The examiner looks for three indicators of impairment in each eye:

• if the eye cannot follow a moving object smoothly
• if jerking is distinct when the eye is at maximum deviation
• if the angle of onset of jerking is within 45 degrees of center

It should be noted, HGN may also indicate consumption of seizure medications, phencyclidine, a variety of inhalants, barbiturates and other depressants.

Walk-and-Turn Testing
In both the walk-and-turn test and the one-leg stand test, the examiner is attempting to determine how well the subject can listen to and follow instructions while performing simple physical movements. These tests are referred to as “divided attention” tests because impaired persons often have difficulty with tasks that require their attention to be split between simple mental and physical exercises.

In the walk-and-turn test, the subject is instructed to take nine steps, heel-to-toe, along a straight line. After taking the steps, the suspect must turn on one foot and return in the same manner in the opposite direction. The examiner looks for seven indicators of impairment:
If the subject...

• cannot keep balance while listening to the instructions
• begins before the instructions are finished
• stops while walking to regain balance
• does not touch heel-to-toe
• uses arms to balance
• loses balance while turning
• takes an incorrect number of steps

One-Leg Stand Testing
In the one-leg stand test, the suspect is instructed to stand with one foot approximately six inches off the ground and count aloud by thousands (One thousand-one, one thousand-two, etc.) until told to put the foot down. The officer times the subject for a 30 seconds. The officer looks for four indicators of impairment:

• swaying while balancing
• using arms to balance
• hopping to maintain balance
• putting the foot down