t What is the Field Sobriety Test?


Field sobriety tests (FST) are agility tests that are used by police officers to determine if a person is impaired by drugs and/or alcohol. If a person is believed to have been driving while under the influence, the officer may request that the person perform a series of field sobriety tests before deciding to make a DUI arrest.  Note that there is no requirement to take the field sobriety test.  If you refuse, you will not face any consequences.  The National Highway Safety and Traffic Administration (NHSTA) has closely regulated field sobriety tests throughout the years. Currently, only three field sobriety tests are considered standardized by the NHSTA. The three standardized field sobriety tests are: the Horizontal Gaze Nystagmus, the Walk-and-Turn, and the One-Leg Stand. 


Horizontal Gaze Nystagmus – An involuntary jerking of the eyeball that occurs naturally as the eyes gaze to the side. Under normal circumstances, nystagmus occurs when the eyes rotate at high peripheral angles. When a person is impaired by alcohol, nystagmus is exaggerated and may occur at lesser angles. An alcohol-impaired person will also often have difficulty smoothly tracking a moving object. In the HGN test, the officer observes the eyes of a suspect as they follow a slowly moving object, often a pen or small flashlight, horizontally with his or her eyes. The officer looks for three indicators of impairment in each eye:


  • If the eye cannot follow a moving object smoothly

  • If jerking is distinct when the eye is at maximum deviation

  • If the angle of onset of jerking is within 45 degrees of center


HGN may also indicate consumption of seizure medications, phencyclidine (PCP), a variety of inhalants, barbiturates, and other depressants.


Divided Attention Testing – The walk-and-turn test and one-leg stand test are both “divided attention” tests. They require a suspect to listen to and follow instructions while performing simple physical movements. Impaired persons typically have difficulty with tasks requiring their attention to be divided between simple mental and physical exercises.


In the walk-and-turn test, the subject is directed to take nine steps, heel-to-toe, along a straight line. After taking the steps, the suspect must turn on one foot and return in the same manner in the opposite direction. The officer looks for seven indicators of impairment:


  • Suspect cannot keep balance while listening to the instructions

  • Begins before the instructions are finished

  • Stops while walking to regain balance

  • Does not touch heel-to-toe

  • Uses arms to balance

  • Loses balance while turning

  • Takes an incorrect number of steps.


Challenging the Field Sobriety Tests


Most people are under the impression that field sobriety tests can determine if a person is impaired by drugs and/or alcohol, but this is not true. In many cases, it has been discovered that people have performed poorly during field sobriety tests for reasons other than intoxication. A person can perform poorly during the field sobriety tests for many reasons, including: slippery road conditions, poor lighting, poor instructions, and medical conditions that impair the person’s coordination.


According to the NHTSA manual,  if the FST tests are not performed properly, or if conducted without adhering to the training protocols, such actions “compromise” the validity of these evaluations. The attorneys at Rollins & Chan usually challenge the subjective nature of FSTs, the accuracy of the principles behind the tests, the accuracy of the administration of the tests, the credibility of the officer who “requested” the tests, and challenge all circumstances connected with the evaluations. An attorney representing you must attack the factual and legal issues that may arise regarding the officer’s scoring and evaluation of the field tests. The reason that most credible scientists across America and in other countries are unwilling to categorize field tests-even NHTSA’s tests-as being scientific is that too many variables are involved in roadside testing to ever eliminate pure chance and non-controlled circumstances from the equation, for example environmental conditions such as lighting and roadway slope.


To have the greatest opportunity of avoiding the many penalties and negative consequences of Washington, D.C. DUI conviction, be sure to contact an attorneyas soon as possible. As an experienced D.C.  DUI lawyers,Rollins & Chan we are here to offer you the aggressive and dedicated representation you deserve. Contact DUI attorney Mark Rollins or Ada Chan today to learn more about how you can avoid serious DUI penalties. 202-455-5610