One Leg Stand (OLS) DWI Field Sobriety Test
The One-Leg Stand field test is a “divided attention” test that requires a DWI suspect to listen to and follow instructions while simultaneously performing physical movements. Impaired persons have difficulty with tasks requiring their attention to be divided between simple mental and physical exercises.
To perform the One-Leg Stand test, the subject is instructed to stand with one foot approximately six inches off the ground and count aloud by thousands (One thousand-one, one thousand-two, etc.) until told to put the foot down. The officer times the subject for 30 seconds. The officer looks for four indicators of impairment, including swaying while balancing, using arms to balance, hopping to maintain balance, and putting the foot down. NHTSA research indicates that 83 percent of individuals who exhibit two or more such indicators in the performance of the test will have a BAC of 0.08 of greater (Stuster and Burns, 1998).