Standardized Field Sobriety Tests, or FSTs, are a battery of 3 tests performed during a traffic stop. Officers perform these tests to determine if a driver is impaired by drugs or alcohol.
The 3 tests were developed in the 1970s by the National Highway Traffic Safety Administration. The tests that make up the FSTs are the horizontal gaze nystagmus (HGN), the walk-and-turn, and the one-leg stand tests.
Horizontal Gaze Nystagmus Test (HGN)
HGN is an involuntary jerking of the eye. One of the many possible causes of HGN is alcohol. In the HGN test, the officer observes the your eyes as you follow a slowly moving object, like a pen or small flashlight. The officer looks for three clues of impairment in each eye:
- The eye cannot follow a moving object smoothly
- Jerking is distinct and sustained at maximum deviation,
- Jerking is distinct and sustained prior to 45 degrees of center.
Officer’s can estimate a BAC of 0.08 or greater if, between the two eyes, four or more clues appear.
Walk and Turn Test
In this test, you take nine steps, touching heel-to-toe, along a straight line. After taking the steps, you turn on one foot and return heel-to-toe in the opposite direction. There are several clues for impairment:
- Cannot keep balance while listening to the instructions
- Begin test before told to
- Stop while walking to regain balance
- Does not touch heel-to-toe
- Uses arms to balance
- Step off the line
- Takes an incorrect number of steps
- Makes an improper turn
One Leg Stand Test
Here, you stand with one foot approximately six inches off the ground. Then, you count aloud by ones beginning with one thousand (one thousand-one, one thousand-two, etc.) until told to put the foot down. The officer times you for 30 seconds. The officer looks for four clues of impairment:
- Swaying while balancing
- Using arms to balance
- Hopping to maintain balance
- Putting the foot down
Do You Have to Perform FSTs?
You do NOT have to perform these FSTs. Refusing will NOT result in an Implied Consent suspension.