The 3 Most Common Field Sobriety Tests in Virginia

Field sobriety tests results are the most common evidence used to prove a charge of driving under the influence, or DUI in Virginia.

The field sobriety tests in Virginia that are used during DUI investigations were developed by the National Highway and Traffic Safety Administration (NHTSA).  They are designed to determine if an individual is impaired for probable cause to arrest for a DUI.

Field sobriety tests in Virginia are divided attention tests.  There are 2 reasons that an officer conducts these tests.  The first is to test if the individual can understand directions.  The second is to test if the individual can perform certain physical dexterity tests.  It is called a divided attention test because the police officer is trying to test whether the individual can pay attention and perform a task at the same time.  Put another way, the test is to determine if the person can follow directions while performing another task.

There are three common field sobriety tests in Virginia that officers use to determine if an individual is impaired under Virginia’s DUI statute.  These are the nine step walk and turn, the one leg lift, and the HGN test.

These tests are instructed by the officer on the scene.

Apparently, individuals who are impaired by alcohol have difficulty dividing their attention between listening to instructions and performing physical acts.

Walk and Turn

The nine step walk and turn requires the accused to walk nine steps in a straight line, heel to toe.  The individual then must turn around and walk nine steps back, heel to toe.  While performing this test, the officer is trained to look for “cues,” or indicators, that one is impaired.  There are eight indicators of impairment:

• If the individual loss balance while listening to the instructions
• Starts to early
• Stops during the walking to fix his balnce
• Fails to touch heel to toe
• Walks off the line
• Uses his or her arm for balance
• Turns improperly
• Does not walk the correct number of steps

Exhibiting 2 of the above cues indicates a blood alcohol concentration over .08%, which is the legal limit in Virginia.

One Leg Stand

The one leg stand requires the accused to lift one leg 6 inches off of the ground.  He must hold it there until the officer tells him that he can put his foot down.  He also must count out loud the whole time as instructed by the officer.

The officer is looking for the following cues:

• Swaying
• Using arms for balance
• Hopping
• Putting his or her foot down
• Two or more indicators indicate a BAC over .08%.

Horizontal Gaze Nystygmus (HGN)

The HGN test is designed to look for an involuntary jerking in the eye as it moves from side to side.   The officer has the individual follow an object from side to side.  The individual is instructed to only move his eyes.  If the individual exhibits 4 “cues”, this indicates that the person is likely impaired.  This involuntary jerking of the eye can indicate impairment because people under the influence of alcohol will exhibit the eye jerking at less extreme angles than people who are not impaired from alcohol.

The indicators that the officer is trained to look for in each eye:

• The eye cannot follow a moving object smoothly
• Jerking is distinct at maximum deviation
• If the angle of onset of jerking is within 45 degrees of the center.

The test allegedly can determine that if the individual exhibits 4 of these clues in each eye, he has a blood alcohol level of .08 or more.

The NHTSA manual itself states that there are other causes for nystigmaus, iuncluding valid medical conditions.  As such, this field sobriety tests should always be challenged by an experienced Fairfax DUI lawyer.