Can Field Sobriety Test Results Be Used Against You?

When a police officer pulls someone over on suspicion of driving while impaired (DWI) in North Carolina, he or she will typically ask the suspect to perform a number of different field sobriety tests (FSTs). The police use these FSTs to look for signs of impairment in order to justify an arrest. You are not required to submit to FSTs in North Carolina. But, if you do, the results will only be used against you.

Types of Field Sobriety Tests Used in North Carolina

In the 1970s, the National Highway Traffic Safety Administration (NHTSA), a division of the U.S. Department of Transportation, began developing a series of three standardized field sobriety tests for assessing whether an individual’s driving abilities may be impaired. These tests have since been scientifically validated for evaluating alcohol impairment, and today they are used by law enforcement offices in North Carolina and nationwide. The NHTSA’s standardized FSTs are:

  • Horizontal Gaze Nystagmus (HGN) Test
  • One-Leg Stand Test
  • Walk-and-Turn Test

However, while these are the ­only scientifically-validated FSTs, police officers continue to use a number of other non-scientific tests as well.

So, What Can the Police Use Against Me?

The police and prosecutors can potentially use your performance on any field sobriety test in order to seek a conviction for DWI. With the NHTSA’s standardized FSTs, the police can testify as to certain specific indicators of impairment:

Horizontal Gaze Nystagmus Test

With the HGN test, the arresting officer may testify as to six signs of impairment (three in each eye):

  • Jerky eye movements while attempting to track a moving object
  • Sustained nystagmus (jerking) when the eyes are all the way to one side
  • Nystagmus beginning before the eyes reach a 45-degree angle

The One-Leg Stand Test

The one-leg stand test involves counting out loud while standing on one foot and focuses on four signs of impairment:

  • Swaying while attempting to maintain balance
  • Using the arms to balance
  • Hopping to stay upright
  • Putting the foot down

The Walk-and-Turn Test

The indicators of impairment on the walk-and-turn test are:

  • Lack of balance while receiving instructions
  • Beginning the test before the officer finishes the instructions
  • Stopping to regain balance while walking
  • Using the arms for balance
  • Stepping off of the line
  • Failing to touch heel-to-toe
  • Making an improper turn
  • Taking too many or too few steps

With each standardized FST, if the police officer observes a certain number of signs, this can be used as evidence of impairment. With the HGN test, the arresting officer must observe four of the six signs. With the one-leg stand and walk-and-turn tests, any two signs are sufficient to justify an arrest for DWI.

While only the NHTSA’s tests have been proven to be scientific, officers may attempt to testify about other methods they used to assess your level of impairment as well. In any event, there are numerous potential defenses to poor performance on an FST – from improper test administration to poor weather conditions. An experienced defense lawyer will be able to spot the issues that can be used to help fight your DWI.

Cheshire Parker Schneider & Bryan, PLLC | Raleigh DUI Lawyers

At Cheshire Parker Schneider & Bryan, PLLC, we have years of experience defending against DWI charges in the Raleigh area, and attorney Collin Cook has been recognized as one of the top DWI lawyers in North Carolina by National Advocacy for DUI Defense. To discuss your case in confidence, call (919) 833-3114 or contact us online today.