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Police are arresting more and more motorists for driving while intoxicated by non-alcoholic substances. These substances primarily include illegal drugs and prescription medications that negatively affect one’s ability to drive.

The traditional way to test for a driver’s state of intoxication is through a Breathalyzer test, but such tests won’t reveal whether someone is intoxicated by drugs or medications, so officers must rely on other means to test for intoxication in the field. This is where the field sobriety test comes in. The field sobriety test is a general test of intoxication that may reveal a driver’s lack of muscle coordination and thinking ability.

The various parts of a field sobriety test

During a field sobriety test, officers in Tennessee may test a motorist by asking him or her to perform various tasks that test the driver’s motor skills, balance and cognitive abilities. Officers must administer the field sobriety test according to specific rules of procedure.

A typical field sobriety test will involve the following:

  • The walk and turn maneuver: Police will ask the driver to walk from heal-to-toe, usually nine steps in one direction in a straight line. Then the motorist will have to turn on one foot and return to the original position while walking heel-to-toe.
  • Horizontal gaze nystagmus: This test will reveal if a driver is intoxicated if the driver’s eyes involuntarily jerk while moving from side to size. In the case of alcoholic impairment, this jerking will be readily apparent while an officer asks the driver to follow an object from side to side with the eyes without moving the head.
  • The stand on one leg test: Police will ask the driver to stand on a single foot with the other foot approximately six inches above the ground, usually for 30 seconds.
  • The looking back test: Officers will ask the test subject to put his or her feet together while standing and looking up and back.
  • Saying the alphabet backward or counting backward: This is hard enough to do while sober. It’s nearly impossible for someone to do while intoxicated.
  • Counting fingers: A severely inebriated person may not be able to count the number of fingers an officer shows.
  • The finger-nose test: The officer will ask the test subject to touch the nose with an index finger.

Field sobriety tests are not always accurate

There are many reasons other than being intoxicated that a driver could fail a field sobriety test. Sometimes, drivers act strangely due to the stress of going through such a test with a police officer and they fail it for that reason. If you failed your field sobriety test, and it led to an intoxicated driving charge, make sure you investigate your legal rights and options. In some cases, the field sobriety test results won’t be admissible in court.