Legal Dictionary


Field Sobriety Tests

Field Sobriety Tests (also known as FSTs) are tests given by police officers in the field—that is, at the scene of the arrest. They are given by police officers to determine whether there is probable cause to arrest the individual for driving under the influence of alcohol or drugs. Some of the Field Sobriety Tests that can be administered by a police officer include:

  • Walk-the-line test — This test is also called the walk and turn test. The officer has the driver walk along a line on the ground, heel-to-toe. At the end of the line he is told to pivot and return. Any inability to walk heel-to-toe smoothly is considered a sign of intoxication by the officer.
  • The one-leg stand — This test requires the driver to stand on one leg for 30 seconds, with the other leg held out at a 45-degree angle. The driver is told place the leg down after 30 seconds have elapsed. Alternatively, the officer could ask the driver to count backwards or to recite the alphabet. Failures to maintain balance, an inability to estimate time correctly, or reciting the alphabet incorrectly are all signs of intoxication.
  • The modified position of attention — Here the driver is directed to stand and tilt his head back with his eyes closed for 30 seconds. This is supposed to be done without any swaying. Any swaying during the 30 seconds is considered a sign of intoxication.
  • Finger-to-nose test — Here the driver is asked to assume a position of attention, tilt the head back and touch the tip of his right index finger to the tip of his nose. He is asked to repeat this with his left index finger. If the driver fails to touch the tip of his finger to the tip of his nose (tip-to-tip) and instead touches the bridge of his nose, it is considered a sign of intoxication by the officer. This may be in part due to the officer's imprecise instructions on the finger-to-nose test.
  • The hand-pat test — The driver is asked to hold one hand palm up, then pat the palm alternately with the back and palm of the other hand in a rapid motion. The officer looks for any chopping, slapping, or going too slowly as indications of intoxications.
  • Reverse counting — The driver is told to count in reverse order. The officer will suggest starting to count at 1000 and counting in reverse until told to stop. Any hesitation or flubs in the reverse sequence is deemed to be a sign of intoxication.
  • Recite alphabet backwards — Here the driver is told to recite the alphabet quickly. If any letters are skipped over, that could be a sign of intoxication.
  • Written alphabet — The driver is asked to write the alphabet on a piece of paper and then put his signature on it. The officer is looking at the correctness of the alphabet or the handwriting itself as a possible sign of intoxication.
  • Nystagmus Tests — This includes the horizontal gaze and vertical gaze nystagmus tests. These tests involve the officer observing the movement of the driver's eyeball on a lateral plane. If there is any eye jerking (nystagmus) and lack of smooth pursuit then the officer may interpret this as signs of intoxication.