Most DUI charges involve a field sobriety test at one point or another. In those cases it is especially important to have an attorney with years of experience in defending against such tests. Understanding the kinds of tests, circumstances and rules surrounding the tests, and what officers are and are not allowed to do in such cases can be crucial to building a solid defense. Such knowledge makes a qualified lawyer indispensable.
Field sobriety tests are classified into two different groups:
- Non-standard field sobriety tests or NSFST
- Standard field sobriety tests or SFST
Standard field sobriety tests are three evaluations that were developed for use by the National Highway Traffic Safety Administration, or NHTSA. These three tests include:
- One-leg stand (OLS)
- Horizontal Gaze Nystagmus (HGN)
- Walk and turn (WAT)
Horizontal Gaze Nystagmus (HGN)
HGN involves the involuntary jerking that the eyes naturally make when moving to the side. This test is frequently administered by asking a person to follow a moving object, such as a finger or pen as it is moved from one side to another in front of the person's face. The person follows the object with their eyes while their head remains stationary. Three indicators that the examiner will look for that indicate impairment include:
- If the eyes are not able to smoothly follow the moving object
- If jerking starts within 45 degrees of center
- If there is distinct jerking when the eyes are at maximum deviation
Walk and Turn (WAT)
The administration of the walk and turn test involves having the person take nine heel-to-toe steps in a straight line. This is followed by a one foot turn and an additional nine steps back. There are 8 indicators of impairment that the examiner will watch for. If the subject:
- Starts the test before the instructions are finished
- Does not touch their feet heel-to-toe
- Cannot maintain balance while standing listening to instructions
- Steps off the line
- Stops during the test in order to regain their balance
- Uses their arms to maintain balance
- Takes the wrong number of steps
- Makes the turn wrong
One-leg stand (OLS)
Conducting the one leg stand requires the person to stand with their foot about 6 inches off the ground while they count out loud to a given number; or, until they are told to stop. There are four indicators the examiner will look for that will indicate impairment:
- Using arms to maintain balance
- Putting a foot down
- Swaying while trying to balance
- Hopping in order to maintain balance
Non-Standard Field Sobriety Tests
Additional mental or coordination test are part of the NSFSTs that an officer can use in order to determine if a subject is impaired. These NSFSTs include:
- Numbers backward test
- ABCs
- Rhomberg balance test
- Hand pat test
- Finger count test
- Finger to nose test