What criteria is used to assess whether the subject has passed or failed the SFST?

The assessment of whether a subject has passed or failed the Standardized Field Sobriety Tests (SFST) relies primarily on the number of clues observed during the tests. This approach is based on standardized criteria that allow law enforcement officials to determine the level of impairment exhibited by a subject. Each SFST is designed to elicit specific physical and behavioral responses that indicate impairment when a suspect is under the influence of alcohol or drugs.

For instance, during the Horizontal Gaze Nystagmus (HGN) test, certain indicators such as the inability to follow a stimulus smoothly, angles of onset exceeding 45 degrees, and nystagmus at maximum deviation are clues used to evaluate impairment. Similarly, during other assessments like the Walk-and-Turn or One-Leg Stand, various movements, balance, and coordination issues serve as clues to determine the subject's condition.

The other criteria listed, such as verbal responses, time taken to complete the tests, and the subject's mood and demeanor, can provide context but do not form the basis of the decision to conclude whether a subject has passed or failed the SFST. The focus is on observable behavior and physical clues during the execution of the tasks rather than subjective measurements or interpretations.