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Field Sobriety Tests

Field sobriety tests are used to determine a person’s blood alcohol level (BAC) or sobriety. It is commonly conducted by trained police officers, but in some cases, these officers fail to perform the sobriety test correctly which in turn gives inaccurate test results that can be used against you in court. Some people who suffer disabilities or others who are receiving medical treatment can easily fall victim to these routine field sobriety tests and be falsely charged.

The most common field sobriety tests used by police officers are:

 

The Horizontal Gaze Nystagmus Test (HGN)
Nystagmus is described as the involuntary eye movement that causes jerking or trembling. It is characterized by alternating smooth movement in one direction and rapid jerking or trembling in the other direction.

The standard way of conducting this Nystagmus test is holding an object or a light (in the officer’s case) 12-15 inches away from the driver’s face and slowly move the object from side to side. In this case, the trained police officer will check for any signs of involuntary movement that can be categorized as Nystagmus. If the driver’s eyes begin jerking prior to reaching 45 degrees, the police officer may determine that the blood alcohol content is above 0.05%.

The Horizontal Gaze Nystagmus Test (HGN) is known to be the most reliable of the three tests. Its accuracy is roughly at 77% which sill leaves plenty of room for error. There are many factors that can determine the accuracy of this test. This depends on the proper training of the officer, proper scoring, and administration. Also, alcohol is not the only cause of nystagmus, there are other causes such as: medications and some prescription drugs, bodily or neurological disorders, excessive amounts of caffeine or nicotine, head trauma and others.

 

The Walk and Turn Test
The Walk and Turn Test is also used by police officers to determine someone’s blood alcohol content level. It is less reliable than the HGN test.

This test must be conducted on a dry, hard, non-slippery surface with sufficient space to walk. The conditions of the area must be of no danger to the person walking if she or he were to fall. The officer instructs the suspect to complete nine heel-to-toe steps on a visible line or walk parallel to the closest curb. The officer then observes any sign of intoxication such as: improper turning, walking off line, heel and toe not touching, incorrect number of steps, and not following instructions.

People with physical impairments have a hard time completing this task. Bad weather conditions can also affect the validity of the test and many other factors.

One Legged Stand Test
Of all three, the one legged stand test is the least reliable.

In order to conduct this test, it must be performed on a dry, level, non slippery surface. The officer instructs the suspect to raise one foot while counting out loud for as many as thirty seconds. The officer is required to stand a few feet away and stay motionless as possible to not interfere with the suspect. The officer will then observe for any clues of intoxication such as: the use of the arms, swaying while balancing, unable to maintain posture, and hopping on one foot to maintain balance.

Many people who have physical disabilities, old of age, or who are over weight can have a difficult time performing this task. Bad weather conditions, wind, and other factors can affect the validity of the test. In many cases, people can be falsely charged with a DUI/DWI even though they were completely sober. 

If you or someone you know is arrested for a DWI/DUI, contact an experienced DWI attorney to help defend your case.

Minneapolis DWI attorney cl will use his experience and knowledge to investigate your case and defend you in court.


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