Types of Field Sobriety Tests in Manassas

Generally speaking, field sobriety tests are an investigative tactic used by police to determine, through objective collection of evidence, whether or not a person is impaired. The following is information on the three different types of standardized field sobriety tests and how they are administered. To learn more or discuss your legal rights, call and schedule a consultation with a Manassas DUI lawyer today.

Horizontal Gaze Nystagmus Test

The “Horizontal Gaze Nystagmus” (“HGN”) is a test where the officer holds a pen or some kind of stylus in front of the person face and asks the person to track the object.  He then observes the individual’s eyes as they track that object laterally from side to side. The officer is looking for the involuntary movement of whether the eye tracks the object smoothly or whether it bounces as it goes along.

There are six different clues that police look when administering the HGN test, three for each eye:

  • First, they look for equal and smooth tracking of the eye.
  • Next, they look for the nystagmus (the bouncing of the eye).
  • Third, police look for whether there is distinct and sustained nystagmus at maximum deviation, which means when the tracking stylus is all the way off to the side, your eyeball to bounces in place as it looks at it.

That test has been authorized and approved by the National Highway Transportation Safety Authority (“NHTSA”). All officers are trained to administer of that test.

Walk and Turn Test

The “Walk and Turn” test is another standardized field sobriety test that has been approved by NHTSA. All officers are trained in the administration of this test as well. The Walk and Turn requires that the person to stand at attention essentially with their arms at their sides and one foot placed in front of the other with the heel touching the toe. During that period of time while the person is standing like that, the officer will instruct him to take nine heel-to-toe steps out.

After nine steps, the person must pivot while keeping one foot flat on the ground and take nine steps back. In some cases, there will be an actual line upon which the subject will perform the test. In other cases, a line will be imaginary (this typically happens where there are no traffic markings on the road that are easily accessible at the time the test is administered).

During a person’s performance of this test, the officer is looking to see if the person is failing to touch heel to toe, failing to stay on the line, using their arms for balance, or not making the turn properly. Also, starting the test before the person is instructed to do so and not counting out loud are red flags to police, as is anything else that deviates from the instructions that they were given.

One Leg Stand Test

The “One Leg Stand” test is the final of the three standardized field sobriety tests approved by NHTSA. Again, all officers are trained in the administration of this relatively basic test. It requires a person is to stand with one leg lifted off the ground about 6-inches while keeping both legs straight at the same time. The goal is not to bend the leg that is being lifted.

Also, the individual must keep his hands at his side and count up starting from one thousand (1001, 1002, 1003) for 30 seconds. And that’s it. It’s very simple. Some of the things that officers look for when administering that test is whether the person is able to complete it, whether the person is able to maintain that position while keeping their arms straight down at the sides, whether they’re able to keep their foot the same amount of – the same height off the ground and so forth.