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Attorneys Jeffrey bullard and Sarah Powell
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What are Standardized Field Sobriety Tests and Do I have to Participate in them?

Posted by on in DUI Defense
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Standardized Field Sobriety Tests (“SFTS”) were developed by the National Highway Traffic Safety Administration or “NHTSA” to assist in the investigation of impaired drivers. Below is a brief description of each test and what “clues” or “cues” of impairment an officer is looking for to determine impairment.

1. Nystagmus Test

            A. Horizontal Gaze Nystagmus Test

The Horizontal Gaze Nystagmus or HGN test is considered the most reliable of the Standardized Field Sobriety Tests. The HGN test is looking for the involuntary jerking of the eyes, occurring as the eyes gaze to the side. When a person is impaired by alcohol or certain drugs, some jerking will be seen if the eyes are moved far enough to the side. If administered correctly, it is considered to be 88% effective in detecting alcohol impairment in a subject.

            i. Administration of Test

           1. Ask the subject to stand with feet together, arms at sides.

           2. Position stimulus, such as pen or finger, 12-15 inches in front of subject and slightly above eye level.

           3. Check for pupil size and resting nystagmus.

           4. Check for equal tracking.

           5. Check for smooth pursuit.

           6. Check for distinct and sustained nystagmus prior to 45 degrees.

           7. Total clues.

           8. Check for vertical nystagmus.

           ii. Clues of Impairment

           1. Lack of Smooth Pursuit - The eyes jerk or bounce as they follow a smoothly moving stimulus, such as a pencil or penlight.

           2. Distinct and Sustained Nystagmus at Maximum Deviation - Distinct and sustained nystagmus is evident when they eye is held at maximum deviation for a minimum of four (4) seconds and continues to jerk toward the side.

          3. Onset of Nystagmus Prior to 45 Degrees - The point at which the eye is first seen jerking. If seen prior to 45 degrees, it indicative of alcohol impairment.

          B. Vertical Gaze Nystagmus Test
Vertical Gaze Nystagmus is an involuntary jerking of the eyes (up and down) which occurs when the eyes gaze upward at maximum elevation for a minimum of four (4) seconds. The presence of this type of nystagmus is associated with high doses of alcohol for that individual and certain other drugs.

2. Walk and Turn Test

The Walk and Turn test is designed as a divided attention test and broken down into two separate components, the instruction phase and the walking stage. Whenever possible, the Walk and Turn test is to be conducted on a reasonably dry, hard, level, non-slippery surface, with sufficient room for a subject to complete nine (9) heel-to-toe steps. If administered correctly, it is considered to be 79% effective in detecting alcohol impairment in a subject.

        A. Instruction Stage

       During this stage of the test, a subject is instructed to do the following:

       1. Place your left foot on the line (real or imaginary).

       2. Place your right foot on the line ahead of the left foot, with the heel of your right foot against the toe of the left foot.

       3. Maintain this position until I have completed the instructions.

       4. Do you understand the instructions thus far?

       B. Walking Stage

During this stage of the test, a subject is instructed to do the following:

       1. When I tell you to start, take nine (9) heel to toe steps on the line, turn and take nine heel to toe steps down the line.

       2. When you turn, keep the front (lead) foot on the line and turn by taking a series of small steps with the other foot, like this.

       3. While you are walking, keep your arms at your sides, watch your feet at all times, and count your steps out loud.

       4. Once you start walking, do not stop until you have completed the test.

       5. You may begin.

       C. Clues of Impairment

       1. Cannot keep balance while listening to instructions.

       2. Starts too soon.

       3. Stops While Walking.

       4. Does not touch heel to toe (more than ½").

       5. Steps off line.

       6. Uses arms to balance (more than 6 in. from side).

       7. Improper turn.

       8. Incorrect number of steps.

If a subject exhibits two (2) of the eight (8) clues listed above, the person is considered to be impaired.

3. One Leg Stand

The One Leg Stand test is designed as a divided attention test and broken down into two separate components, the instruction phase and the balance and counting stage. If administered correctly, it is considered to be 83% effective in detecting alcohol impairment in a subject.

       A. Instruction Phase

During this stage of the test, a subject is instructed to do the following:

      1. Please stand with your feet together and your arms down at your sides.

      2. Do not start to perform the test until I tell you to do so.

      3. Do you understand the instructions, thus far.

B. Balance and Counting Stage

During this stage of the test, a subject is instructed to do the following:

     1. When I tell you to start, raise either leg with the foot approximately six (6) inches off the ground, keeping your foot parallel to the ground.

     2. Keep both legs straight and your arms at your side.

     3. While holding that position, count out loud in the following manner, “one thousand one, one thousand two, one thousand three,” and so on until told to stop.

     4. Keep your arms at your sides at all times and keep watching the raised foot.

     5. Do you understand?

     6. You may begin.

     C. Clues of Impairment

    1. Sways while Balancing.

    2. Uses Arms to Balance.

    3. Hopping.

    4. Puts foot down.

If a subject exhibits two (2) of the four (4) clues listed above, the person is considered to be impaired.

4. Preliminary Alcohol Screening Test

The Preliminary Alcohol Screening Tests is a breath test that is typically administered by the investigating officer at the scene of the DUI investigation. Preliminary breath testing is a stage of the pre-arrest screening of a DUI subject where the subject is not yet under arrest. The purpose of the test is to provide evidence that alcohol is the chemical basis of the impairment of the subject.

CAUTION
ALL FIELD SOBRIETY TESTS IN CALIFORNIA ARE CONSIDERED VOLUNTARY, MEANING YOU DO NOT HAVE TO PARTICIPATE IN THE TESTS