Field Sobriety Tests

DWI Lawyer Fairfax VA

Field Sobriety TestsField sobriety tests often include a couple of evaluations performed by a police officer to help determine whether a driver is under the influence. The actions of the driver are used to assess the level of coordination, balance, and attention. The tests commonly used in a field sobriety test include horizontal gaze nystagmus (HGN) and the walk-and-turn.

In the majority of circumstances, these tests have been scientifically proven to correctly determine whether a driver is under the influence or not. However, if an officer does not perform the test properly, this can skew the results and make a driver who is actually innocent look quite guilty.

The Fairfax VA DWI lawyers at May Law, LLP have been helping build defense cases for those accused of a crime for more than 20 years. Please read on for more information about field sobriety tests and reach out to a DWI lawyer for additional questions.


An officer who asks the driver to walk nine steps in a heel-to-toe fashion along a painted straight line and then turn on one foot to come back in the opposite direction is likely conducting a walk-and-turn test. During this evaluation, the officer is looking for:

  • Whether the driver cannot keep his or her balance while listening to the instructions being given
  • Whether the driver begins the test before the instructions are fully explained
  • Whether the driver is not able to walk with coordination and keeps trying to regain balance
  • Whether the driver does or does not touch heel-to-toe
  • Whether the driver uses his or her arms as balance

As a DWI lawyer at May Law, LLP understands, just because a driver does not take exactly nine steps or uses arms as balance, this does not necessarily mean he or she is intoxicated. Many people may use their arms as a natural response to maintaining balance, especially when asked to perform such a peculiar task. In a moment of panic after being pulled over by a cop, the driver may not complete the task to his or her true capacity out of nervousness.

Horizontal Gaze Nystagmus (HGN)

An officer who asks a driver to focus on a pen, while slowly waving it back and forth is likely performing a horizontal gaze nystagmus (HGN) test. This is when the officer looks for an involuntary jerking of the eye, to evaluate whether a person may have been drinking and driving. But, this type of movement can happen to anyone when the eyes are rotated at a higher peripheral angle. If the officer has not been trained properly in how to perform such a test, an incorrect assumption could be made. During this test, the officer is looking to determine whether:

  • The eye can or cannot follow the object in a smooth motion
  • The jerking is very apparent when the eye is at maximum deviation
  • The angle of the jerking movement is within a 45-degree angle

If you have been recently arrested and accused of a DUI, we highly recommend calling to book an appointment with a DWI lawyer Fairfax VA clients recommend from May Law, LLP immediately.

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