n California, field sobriety tests are completely voluntary for drivers 21 years of age or older. It is strongly advised that you politely decline performance of these exercises.
Horizontal Gaze: Nystagmus
The Police Officer positions an object such as pen or penlight approximately 1 foot in front of the subject's face driver's face while instructing the subject to focus and follow the object with their eyes without moving their head, while the officer moves the object from side to side while watching the subject's eyes and trying to detect trembling of the eye or involuntary jerking as an indication of impairment.
Walk and Turn Test
Walk and Turn: The subject takes nine heel-to-toe steps along a line, turns, and takes nine heel-to-toe steps back. The police officer is trying to detect if accused can keep their balance, take direction, start too soon, pause and resume during the test, leave space between heel and toe, overstep the line, or lose balance while turning.
One Leg Stand
The police officer instructs the subject to stand steadily with arms at their side and heels and feet together. Next, he instructs the subject to raise one leg only six inches above the ground until instructed to release the raised leg. The Police Officer is trying to detect swaying, hopping, loss of balance, raised arms, muscular tension, and coordination.
Rhomberg Balance Test
The subject is told to stand at attention, tilt head back while closing eyes, and estimate what they believe to be a thirty second time span. The police officer is observing shiftiness, unsteadiness, tremors, muscular tension, perception of time, coherence, balance and coordination.
Touch Nose with Finger Test
The Police Officer instructs the subject to stand with feet together and eyes closed. Subject is then instructed to touch their nose with their index finger without swaying or losing balance.