In administering the HGN test, the officer has the suspect follow the motion of a small stimulus (approximately 12-15 inches from the subject’s face) with the eyes only. The stimulus may be the tip of a pen, finger or penlight. When the HGN test is administered, the officer always begins with the subject’s left eye. Each eye is examined for three specific clues. As the eye moves from side to side, does it move smoothly, or does it jerk noticeably? When the eye moves as far to the side as possible and is kept at that position for several seconds (minimum of four seconds), does it jerk distinctly? As the eye moves slowly towards the side, does it start to jerk prior to a 45-degree angle? The maximum number of clues that appear in one eye is three. The maximum total number for any subject is six. Research shows that if four or more clues are evident, the test is 88% percent reliable at indicating a person’s BAC is .08 or higher. Walk and Turn (WAT): A divided-attention test consisting of two stages: (1) Instruction Stage and (2) Walking Stage. Research shows that if a subject exhibits two or more clues, the test is 79% reliable at indicating a person’s BAC is .08 or higher. One-Leg Stand (OLS): It is a divided-attention test consisting of two stages: (1) Instruction Stage and (2) Balance and Counting Stage. Research shows that, when the suspect produces two or more clues, the test is 83% reliable at indicating a person’s BAC is .08 or higher. Preliminary Breath Test (PBT): The basic purpose of a PBT is to demonstrate the association of alcohol with the observable evidence of the subject’s impairment. The PBT result is only one of many factors the officer considers in determining whether the subject should be arrested. It should never be the sole basis for an arrest. The Arrest Decision: Your arrest/no arrest decision is “based on the totality of the circumstances” of the three phases of an impaired driving investigation. If all the evidence, taken together, establishes probable cause to believe a crime has been committed, you should arrest the subject for impaired driving. Three Phases of an Impaired Driving Investigation are Essential for a Proper Police Report
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Walk & Turn Test 8 Clues:
1. Cannot balance during instructions 2.Starts too soon 3.Stops while walking 4. Does not touch heel- to-toe 5.Steps off the line 6.Uses arms to balance 7. Loses balance on turn or turns incorrectly 8. Takes the wrong number of steps
One-Leg Stand Test 4 Clues:
1.Sways while balancing 2.Uses arms to balance 3. Hops 4.Puts foot down
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Mothers Against Drunk Driving ®
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