Divided Attention Testing
The walk-and-turn test and one-leg stand test are "divided attention" tests that are easily performed by most sober people. They require a suspect to listen to and follow instructions while performing simple physical movements. Impaired persons have difficulty with tasks requiring their attention to be divided between simple mental and physical exercises.
Walk-and-Turn
In the walk-and-turn test, the subject is directed to take nine steps, heel-to-toe, along a straight line. After taking the steps, the suspect must turn on one foot and return in the same manner in the opposite direction. The examiner looks for seven indicators of impairment:
- Suspect Cannot Keep Balance While Listening to the Instructions
- Beginning Before the Instructions are Finished
- Stops While Walking to Regain Balance
- Does Not Touch Heel-to-Toe
- Uses Arms to Balance
- Loses Balance While Turning
- Takes an incorrect Number of Steps
NHTSA research indicates that 68 percent of individuals who exhibit two or more indicators in the performance of the test will have a BAC of .08 or greater.
One-Leg Stand
In the one-leg stand test, the suspect 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
- Putting the Foot Down
NHTSA research indicates that 65 percent of individuals who exhibit two or more such indicators in the performance of the test will have a BAC of .08 of greater.
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Horizontal Gaze Nystagmus
