SFST Evaluation Factors 1 — Questions and Answers

Question 1: Which of the following is NOT one of the three main components of SFST?

Horizontal Gaze Nystagmus (HGN)
Walk-and-Turn (WAT)
One-Leg Stand (OLS)
Breathalyzer test (Correct answer)

Correct answer: Breathalyzer test

The three main components of the Standardized Field Sobriety Tests (SFSTs) are the Horizontal Gaze Nystagmus (HGN), the Walk-and-Turn (WAT), and the One-Leg Stand (OLS). These are psychophysical tests designed to assess impairment through observable physical and mental faculties. A breathalyzer test, while often used in DUI investigations, is a chemical test that measures Blood Alcohol Content (BAC) and is separate from the SFST battery, which relies on behavioral observations.

Question 2: The Horizontal Gaze Nystagmus (HGN) test measures what?

Balance and coordination
Eye movements to detect impairment (Correct answer)
Walking ability
Ability to follow instructions

Correct answer: Eye movements to detect impairment

The Horizontal Gaze Nystagmus (HGN) test specifically measures involuntary jerking of the eyes as they gaze to the side. Alcohol and certain drugs impair the brain's ability to control eye movements smoothly, leading to more pronounced nystagmus. Observing these specific eye movements helps officers detect signs of central nervous system impairment, which is a key indicator of intoxication.

Question 3: What is the purpose of the Walk-and-Turn (WAT) test?

To check the subject's ability to remember instructions
To test the subject's balance and coordination while walking (Correct answer)
To measure the subject's reaction time
To assess eye movements

Correct answer: To test the subject's balance and coordination while walking

The Walk-and-Turn (WAT) test is a divided attention test designed to assess a subject's ability to follow instructions and maintain balance and coordination simultaneously. It requires the subject to walk a straight line, turn, and return, while officers observe for specific clues of impairment such as losing balance, stepping off the line, or using arms for balance. These actions directly test motor skills and cognitive functions affected by alcohol.

Question 4: What is a key sign of impairment observed during the One-Leg Stand (OLS) test?

Difficulty keeping the eyes open
Inability to balance on one foot (Correct answer)
Sweating excessively
Rapid speech

Correct answer: Inability to balance on one foot

The One-Leg Stand (OLS) test is a divided attention test that requires a subject to balance on one foot for a sustained period while counting. A key sign of impairment observed during this test is the inability to maintain balance, which can manifest as swaying, hopping, putting the foot down, or using arms for balance. These actions indicate impaired motor control and coordination due to alcohol or drug influence, making it a reliable indicator of intoxication.

Question 5: Which of the following factors can affect the accuracy of the SFST results?

The subject's gender
Environmental conditions like weather or lighting (Correct answer)
The color of the subject’s clothing
The time of day

Correct answer: Environmental conditions like weather or lighting

The accuracy and validity of SFST results can be significantly influenced by various environmental factors. Poor lighting can make it difficult for officers to observe subtle clues, while uneven surfaces, strong winds, or extreme temperatures can affect a subject's balance and performance, potentially leading to inaccurate interpretations of impairment. Officers are trained to consider and mitigate these conditions to ensure reliable test results.

SFST Evaluation Factors 1

Which of the following is NOT one of the three main components of SFST?