SFST Court Testimony 2 — Questions and Answers
Question 1: When cross-examined about HGN testing, which foundational point should an SFST officer be prepared to establish first?
- The defendant's prior DUI history
- Scientific validity of HGN as an impairment indicator (Correct answer)
- The officer's opinion of the defendant's guilt
- The weather conditions at the time of the stop
Correct answer: Scientific validity of HGN as an impairment indicator
Before HGN evidence is admitted, the officer must establish that the test is based on sound scientific principles linking nystagmus to alcohol impairment.
Question 2: An officer is asked on the stand: 'Did you record the exact angle of onset of nystagmus?' The best response if no angle was measured is:
- Claim an angle was measured to appear thorough
- Admit no angle measurement was taken and explain it is not required by NHTSA protocol (Correct answer)
- Refuse to answer the question
- State the angle was approximately 45 degrees
Correct answer: Admit no angle measurement was taken and explain it is not required by NHTSA protocol
NHTSA SFST protocol does not require officers to measure precise angles; honest acknowledgment of this avoids impeachment.
Question 3: During direct examination, the prosecutor asks the officer to describe the Walk-and-Turn test. The officer should emphasize:
- Their personal belief that the defendant was drunk
- The specific observed clues and how each correlates to impairment (Correct answer)
- That the test is infallible
- The defendant's rude behavior during the stop
Correct answer: The specific observed clues and how each correlates to impairment
Testimony should focus on observable, documented clues and their validated correlation to BAC of 0.08 or higher.
Question 4: Defense counsel asks: 'Isn't it true that innocent medical conditions can cause HGN?' The officer's most accurate response is:
- No, HGN is always caused by alcohol
- Yes, certain medical conditions can cause nystagmus, which is why officers are trained to screen for them (Correct answer)
- The question is irrelevant to the case
- Only DUI suspects have nystagmus
Correct answer: Yes, certain medical conditions can cause nystagmus, which is why officers are trained to screen for them
Officers are trained to identify medical or other non-alcohol causes of nystagmus, and acknowledging this demonstrates thorough training.
Question 5: What is the evidentiary purpose of an officer referencing NHTSA training materials during court testimony?
- To show the officer personally invented the tests
- To establish that the tests were administered according to validated, standardized procedures (Correct answer)
- To impress the jury with technical jargon
- To introduce evidence that was not part of the original report
Correct answer: To establish that the tests were administered according to validated, standardized procedures
Referencing NHTSA standards confirms the officer followed validated protocols, supporting admissibility and weight of SFST evidence.
Question 6: If an officer cannot remember a specific detail from the field sobriety test during testimony, the best practice is to:
- Fabricate a plausible detail
- State the detail from memory even if uncertain
- Ask to review the arrest report or notes taken at the time (Correct answer)
- Decline to answer entirely
Correct answer: Ask to review the arrest report or notes taken at the time
Officers may refresh their recollection by reviewing contemporaneous reports or notes, which is legally permissible during testimony.
Question 7: When testifying about the One-Leg Stand, an officer states the suspect 'almost fell.' The defense objects that this is speculative. The officer should clarify by:
- Arguing with defense counsel
- Describing the exact observable behavior, such as 'the suspect raised their arms and hopped to maintain balance' (Correct answer)
- Withdrawing the statement entirely
- Asking the judge to overrule the objection
Correct answer: Describing the exact observable behavior, such as 'the suspect raised their arms and hopped to maintain balance'
Replacing vague characterizations with specific, observable behaviors makes testimony factual rather than speculative.
SFST Court Testimony 2
When cross-examined about HGN testing, which foundational point should an SFST officer be prepared to establish first?