One Leg Stand Flashcards

In a DUI trial, an officer testifies that the defendant exhibited 3 of 4 OLS clues. According to NHTSA research, what does this suggest about the likelihood of impairment?

Answer: Two or more clues indicate a high probability of BAC at or above the legal limit

NHTSA research establishes that two or more OLS clues are associated with a high probability that the subject's BAC is at or above 0.10.

An officer administers OLS on a sloped roadway shoulder. How does this affect the test results?

Answer: It may produce false clues unrelated to impairment and should be noted

Uneven or sloped surfaces can cause balance difficulty independent of impairment, potentially generating invalid clues that must be documented.

When does the officer begin counting the 30-second OLS period?

Answer: When the subject raises their foot off the ground

The 30-second timing begins when the subject actually lifts their foot, marking the start of the balancing phase.

A defense attorney argues that OLS is not scientifically valid. What is the strongest counter-argument based on NHTSA history?

Answer: OLS was developed and validated through NHTSA-sponsored laboratory and field studies in the late 1970s

The OLS test was developed through systematic NHTSA-funded research in the late 1970s and has been repeatedly validated in subsequent studies.

If a subject refuses to perform the OLS test, what should the officer do?

Answer: Note the refusal, document observations, and consider other evidence of impairment

A refusal is documented and may itself be used as evidence of consciousness of guilt, but officers rely on all available observations.

Which of the following statements about OLS as part of the standardized SFST battery is most accurate?

Answer: OLS should be interpreted alongside HGN and WAT results for a holistic impairment assessment

NHTSA recommends using all three standardized tests — HGN, WAT, and OLS — together because the battery as a whole is more accurate than any single test.

During OLS, a subject keeps their foot raised for 30 seconds but exhibits continuous swaying throughout the test. How should this be scored?

Answer: One clue: swaying while balancing

Swaying is scored as a single clue regardless of duration or frequency; completing 30 seconds does not eliminate clues that occurred during the test.