California law enforcement officers have many tools to use in identifying drunk drivers. One of the first things an officer usually asks of a suspect is a field sobriety test. The test results are often used as evidence in court. What exactly are these tests?

The National Highway Traffic Safety Administration examines standardized field sobriety tests. All field sobriety tests check certain things that alcohol could affect. They include balance, clarity of thought, speech and ability to process directions. Law enforcement officers often use the tests to see if further testing is needed.

Because standardized field sobriety tests have set standards, officers are more likely to use these tests.  That does not mean that such tests are foolproof.

Standardized field sobriety tests include:

  • The horizontal gaze nystagmus
  • The walk-and-turn
  • The one-legged stand

The first test checks your vision for shakiness. An officer will ask you to follow an object’s movement with only your eyes. People under the influence often have a shake to their eye movement and cannot follow light without their eyes jerking.

The second and third tests both check your balance. The walk-and-turn requires you to walk heel to toe in one direction, turn and walk the same way back. The one-legged stand requires you to stand with one foot about 6 inches above the ground and hold the position for a time. After considering the results, an officer may decide whether to let you go or to continue testing.

There are many reasons that a person might fail a standardized test even if he or she has not been drinking. The results of such test are not foolproof and officers do make mistakes.