Fairfax DUI Lawyer explains Field Sobriety Tests used for Fairfax County DUI charges

Criminal Defense Attorneys Serving Fairfax, Leesburg & Manassas, Virginia


The Field Sobriety Tests used for Fairfax County DUI charges

Virginia State Troopers and Fairfax County police officers use Field Sobriety Tests (FSTs) to test someone suspected of driving under the influence of alcohol or drugs in Fairfax.   The officers and troopers observe the driver perform the DUI field sobriety tests to determine if there is "probable cause" to arrest the driver for DUI.

If the driver performs the tests, in the eyes of the officer, satisfactorily, the officer should let the driver go without being arrested.  However, many times the law enforcement officer does find fault in the performance of the tests and makes a DUI arrest in Fairfax County.

This arrest still may not be legal.  Your DUI lawyer can challenge whether the officer made the right decision to make the arrest.  The lawyer can file a "Motion to Suppress, " based upon the officer's lack of "probable cause".  A Fairfax County judge will then evaluate whether the police officer made the correct decision.  If a judge finds that the Fairfax officer lacked "probable cause" to make a DUI arrest because the driver's performance of the field sobriety tests was adequate, the case may be dismissed.

Examples of common Fairfax Field Sobriety Tests (FSTs) include:

  • Horizontal gaze nystagmus (HGN)
  • Nine-step walk and turn
  • One-leg stand
  • Nose touch
  • Alphabet
  • A Field Breathalyzer Test

 officer can request that you take a field sobriety test (FST) and possibly more than one FST. FSTs are voluntary in Virginia, meaning that you have the right to refuse to take these tests. Refusal cannot be used against you in court. FSTs are used to establish probable cause for a DUI arrest.


FSTs that are administered improperly is not valid. Our DUI defense attorneys will ask you questions about your FST, including the instructions given to you by the officer and if the officer demonstrated how to perform the tests. Other factors, including medical conditions, can also invalidate the results of FSTs. Attorneys Alex Gordon and Carlos Wall have extensive experience cross-examining officers in court regarding FSTs and holding them accountable for any errors in administration.