Procedure:
(1) The person stands on one leg with the other foot about 6 inches from the ground.
(2) The person counts aloud by one-thousands (one thousand one, one thousand two, one thousand three, etc.) which approximates seconds.
(3) The stance is maintained for 30 seconds while the observer times the subject (who should have counted up to one thousand 30).
Clues to possible intoxication:
(1) The person sways.
(2) The person uses his or her arms to try to balance self.
(3) The person starts to hop in an attempt to maintain balance.
(4) The person puts the other foot down before 30 seconds have passed.
where:
• I would think that the person being unable to count properly while balancing would also be an indicator.
If the person is unable to perform the test then the person is assumed to have all 4 clues.
Interpretation:
• minimum number of clues: 0
• maximum number of clues: 4
• The presence of 2 or more clues correlates with a blood alcohol concentration (BAC) >= 0.08 g/dL.
Performance:
• In an NHTSA study 83% of persons with >= 2 clues had a BAC >= 0.08 g/dL.
