OPA SFST STUDY GUIDE QUESTIONS WITH CORRECT ANSWERS LATEST UPDATE 2026
What % BAC does your body process alcohol at? - Answers .015 per hour
What was the study that determined the numbers for accuracy? - Answers San Diego Study
What are you trying to determine during phase 1 of OWI? - Answers Whether or not you can stop a
vehicle. Initial observation of vehicle in motion
What are you trying to determine during phase 2 of OWI? - Answers Whether or not you can ask the
driver to step out of the vehicle to complete field sobriety tests. Face-to-face observation and
interview
What are you trying to determine during phase 3 of OWI? - Answers Whether or not you can arrest
the driver for OWI. Pre-arrest screening SFSTs and PBTs
What is the accuracy for horizontal gaze nystagmus (HGN) and vertical gaze nystagmus (VGN)? -
Answers 88% accurate at a BAC of .08
How many clues are there for HGN? - Answers 6 total clues, 3 clues per eye (lack of smooth pursuit,
distinct and sustained nystagmus at maximum deviation, and onset of nystagmus prior to 45 degrees)
How many clues do you need for HGN for a good case? - Answers 4+ clues
What are the stages for HGN? - Answers Medical stage (making sure there's no resting nystagmus,
equal pupil sizes), testing stage (lack of smooth pursuit, distinct and sustained nystagmus at maximum
deviation, and onset of nystagmus prior to 45 degrees)
What is the accuracy for walk and turn (WAT)? - Answers 79% accurate at a BAC of .08
How many clues are there for WAT? - Answers 8 clues (BS SO WHAT) (Balance, Starts too early, Stops,
Off line, Wrong number of steps, Heel-to-toe, Arms, Turn)
How many clues do you need for WAT for a good case? - Answers 2+ clues
What are the stages for WAT? - Answers Instruction stage, walking stage
What is the accuracy for one leg stand (OLS)? - Answers 83% accurate at a BAC of .08
How many clues are there for OLS? - Answers 4 clues (PUSH) (Puts foot down, Uses arms to balance,
Sways while balancing, Hopping)
How many clues do you need for OLS for a good case? - Answers 2+ clues
What are the stages for OLS? - Answers Instruction stage, balance and counting stage
If you notice resting nystagmus or unequal pupils, what should you do? - Answers Contact EMS for a
possible head injury
Things to observe when interviewing a potentially drunk subject operating a motor vehicle - Answers
Bloodshot eyes, soiled clothing, fumbling fingers, alcohol containers, drugs/paraphernalia, bruises,
bumps, scratches, unusual actions, slurred speech, admission of drinking, inconsistent responses,
unusual statements, abusive language, smells of alcoholic beverage, marijuana, coverup odors
Before administering HGN, what should you ask the subject about? - Answers Whether they wear
contacts or glasses, and if they wear contacts, whether they're colored, soft, or hard contacts
Before administering SFST's, what should you do? - Answers Ask the subject medical questions
When administering HGN, how should you have the subject faced? - Answers Away from your patrol
car lights
Is a preliminary breath test (PBT) admissible in court? - Answers No
When administering HGN/VGN, how far away should the stimulus be away from the person's face? -
Answers 12-15 inches away, and slightly above eye level
Can the same clue be used against a subject numerous times? - Answers No
What % BAC does your body process alcohol at? - Answers .015 per hour
What was the study that determined the numbers for accuracy? - Answers San Diego Study
What are you trying to determine during phase 1 of OWI? - Answers Whether or not you can stop a
vehicle. Initial observation of vehicle in motion
What are you trying to determine during phase 2 of OWI? - Answers Whether or not you can ask the
driver to step out of the vehicle to complete field sobriety tests. Face-to-face observation and
interview
What are you trying to determine during phase 3 of OWI? - Answers Whether or not you can arrest
the driver for OWI. Pre-arrest screening SFSTs and PBTs
What is the accuracy for horizontal gaze nystagmus (HGN) and vertical gaze nystagmus (VGN)? -
Answers 88% accurate at a BAC of .08
How many clues are there for HGN? - Answers 6 total clues, 3 clues per eye (lack of smooth pursuit,
distinct and sustained nystagmus at maximum deviation, and onset of nystagmus prior to 45 degrees)
How many clues do you need for HGN for a good case? - Answers 4+ clues
What are the stages for HGN? - Answers Medical stage (making sure there's no resting nystagmus,
equal pupil sizes), testing stage (lack of smooth pursuit, distinct and sustained nystagmus at maximum
deviation, and onset of nystagmus prior to 45 degrees)
What is the accuracy for walk and turn (WAT)? - Answers 79% accurate at a BAC of .08
How many clues are there for WAT? - Answers 8 clues (BS SO WHAT) (Balance, Starts too early, Stops,
Off line, Wrong number of steps, Heel-to-toe, Arms, Turn)
How many clues do you need for WAT for a good case? - Answers 2+ clues
What are the stages for WAT? - Answers Instruction stage, walking stage
What is the accuracy for one leg stand (OLS)? - Answers 83% accurate at a BAC of .08
How many clues are there for OLS? - Answers 4 clues (PUSH) (Puts foot down, Uses arms to balance,
Sways while balancing, Hopping)
How many clues do you need for OLS for a good case? - Answers 2+ clues
What are the stages for OLS? - Answers Instruction stage, balance and counting stage
If you notice resting nystagmus or unequal pupils, what should you do? - Answers Contact EMS for a
possible head injury
Things to observe when interviewing a potentially drunk subject operating a motor vehicle - Answers
Bloodshot eyes, soiled clothing, fumbling fingers, alcohol containers, drugs/paraphernalia, bruises,
bumps, scratches, unusual actions, slurred speech, admission of drinking, inconsistent responses,
unusual statements, abusive language, smells of alcoholic beverage, marijuana, coverup odors
Before administering HGN, what should you ask the subject about? - Answers Whether they wear
contacts or glasses, and if they wear contacts, whether they're colored, soft, or hard contacts
Before administering SFST's, what should you do? - Answers Ask the subject medical questions
When administering HGN, how should you have the subject faced? - Answers Away from your patrol
car lights
Is a preliminary breath test (PBT) admissible in court? - Answers No
When administering HGN/VGN, how far away should the stimulus be away from the person's face? -
Answers 12-15 inches away, and slightly above eye level
Can the same clue be used against a subject numerous times? - Answers No
