What are the 3 field sobriety tests sanctioned by the NHTSA?

Police or patrol officers often use formal and informal field sobriety tests to help them determine if the driver of a motor vehicle is impaired. The Breathalyzer is a formal test that measures the amount of alcohol in a driver’s breath. In Maryland, a person who registers over the legal limit of .08 blood alcohol content can be arrested for drunk driving.

Even when someone registers below a .08 BAC, a police officer can still make an arrest if her or she has probable cause to believe that the driver was impaired at the time. The National Highway Traffic Safety Administration (NHTSA) developed and trains officers across the country on three Standardized Field Sobriety Tests. What are they and what do they test?

The three Standardized Field Sobriety Tests sanctioned by the NHTSA are:

  • Horizonal Gaze Nystagmus: This tests a driver’s nystagmus or ability to track a moving object smoothly, without jerking their eyes. Some seizure medications and other prescription medications can also cause this reaction.
  • Walk and Turn: This tests the drivers ability to focus on both physical and mental exercises. An officer will ask the driver to walk precisely on a straight line, turn on the line and walk back again. If the person sways, uses his or her arms to balance or steps off the line, it is an indication of impairment.
  • One Leg Stand: This is very similar to the walk and turn, testing “divided attention.” The driver must stand on one leg and hold the other about six inches off the ground. They have to hold this position for 30 seconds while counting aloud “one-thousand-one, one-thousand-two.” If the driver loses balance or puts his or her foot down, it is an indication of impairment.

The reality is that these tests are not as reliable as the NHTSA may think or data may show. While they might indicate impairment for some people, other people may be unable to pass the test sober. Try the one-leg-stand test; can you hold the pose for 30 seconds? Even Breathalyzers are notoriously prone to device and human error.

Anyone who is arrested for DUI after failing any combination of these field sobriety tests should know that their situation is not hopeless. They should always invoke their right to an attorney and get individualized legal advice.

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