Types of Field Sobriety Tests in Prince George’s County

Standard Field Sobriety Testing is commonly used by officers and are tests that have been approved by the National Highway Traffic Safety Administration (NHTSA) as the most reliable Field Sobriety Tests. Below, a Prince George’s County field sobriety tests lawyer discusses these tests and what law enforcement is looking for when administering them.

Horizontal Nystagmus Test

So the HGN test, or Horizontal Gaze Nystagmus test, is involuntary jerking of the eye that occurs naturally as the eyes gaze from side to side. The test requires you to follow a pen with your eyes left and right. Under normal circumstances, your eyes would rotate normally back and forth, left and right. However, when you are impaired by alcohol, the angle that you are able to follow will lessen. There is also an exaggeration to the movement and the tracking will not be smooth.

The results of the test can be very subjective, however. The pen has a bright light and the test is usually done during when it is dark out. Your eyes have to adjust to light all while this stimulus is moving back and forth in the hand of an officer. In addition, you may have astigmatism that can impede on the reliability of the test. This is what an officer is looking for and some of the factors that may affect your performance on the scoring of the test. Law enforcement believes there is a higher likelihood of failing the test if you are under the influence of either drugs or alcohol. So, the higher the score, the more likelihood you are under the influence or impaired.

Walk and Turn Test

This test is generally termed as divided attention test and while it seems as though they should be easy for any individual to perform, they’re designed to simultaneously test your physical and cognitive skills in a way that is confusing, unnatural and against your favor. You put one foot in front of the other, you walk on a line, and you turn and come back. They are not actually that easy, however.  Trying to walk while touching heel to toe repeatedly is not a natural gait. The test also requires you to keep your balance on a line that is probably not actually there during the test. Usually you have to imagine this line. Moreover, they have you turn left at the end which for most people is not as natural a movement as turning right.

The tester is judging you on each step, on the distance between the feet, whether you touch toe to heel, whether you step off the line, and whether you use your hands to balance. In the Walk and Turn there are eight indicators. The more indicators you meet, the belief is that it is more likely you have some form of drug or alcohol in your system according to the NHTSA standards.

One Leg Stand Test

The One Legged Stand is more of a physical test. Each officer has it performed slightly differently. The common elements of the test are to raise one leg at least six inches off the ground and count out loud until the offer tells you to stop and lower your leg. The correct instructions are to, “Count 1001, 1002 keeping your foot 6 inches off the ground and don’t put your foot down until I tell you.”

The officer will watch the test for an observation period of 30 seconds and is looking for four indicators. Again, the fewer of the indicators you meet, the more likely NHTSA standards indicate you are under the influence of some alcohol or drugs.

In the end, the tester will combine those three tests to give you a overall score, the consistent high scores and the presumption that you are more likely than not to be under the influence or impaired. The NHTSA research and testing suggests that there is accuracy behind it, depending on how high your scores are.