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Our Ann Arbor Drunk Driving Defense Attorneys Explain Field Sobriety Tests 

A police officer who pulls over a driver and suspected he or she is operating under the influence will ask the person to perform what are called standardized field sobriety tests.The tests are designed to allow the officer to obtain evidence that a person is impaired in order to make an arrest. The tests are often inaccurate, and our Ann Arbor drunk driving defense attorneys are prepared to help you challenge your arrest. 

What are the Field Sobriety Tests Used in Michigan?

There are three standardized field sobriety tests. Standardized means the test must be administered to the driver in the exact same way every time. Failure to administer the test in the right way means the results from that test are invalid. We cannot judge the performance of the person taking the test if they were given the test incorrectly, and our Ann Arbor drunk driving defense attorneys are prepared to help you challenge the results. 

A police officer will ask the driver to take these field sobriety tests in DUI investigations unless there is a reason not to, such as the person is unable to physically or otherwise complete the test.

Horizontal Gaze Nystagmus Test

In the HGN test, a police officer looks for the twitching of a person's eyes to determine the presence of alcohol or drugs. This twitching of the pupil is natural, though alcohol and drugs will increase the twitching. The officer will ask the driver to follow a moving object such as a flashlight that the officer will move back and forth in front of the person's face. 

Walk and Turn

The officer asks the person to stand in a "starting position" while listening to instructions. Then the person will walk nine steps forward, complete a turn, and walk nine steps back. The person is supposed to walk on a straight line, although the line is generally imaginary. The officer is looking to evaluate how the person balances on the imaginary line, the movement of the person's hands and feet, and the ability to follow directions. 

One-Leg Stand

In this test, the person stands on one leg while counting. The officer looks to evaluate the person's balance, specifically whether the person puts their foot on the ground or uses arms for balance. 

Additional Tests

There are further tests which are taught for officers who go through additional education, called Advanced Roadside Impairment Driving Enforcement. These include the Vertical Gaze Nystagmus Test and the Modified Rhomberg Test. 

Non-Standardized Tests

Every once in a while, the officer cannot use the standardized tests because the person has a physical problem, such as a hip or knee replacement. In these cases, the officer might have the person complete a non-standardized test. These are tests that have basically been passed from officer to officer. For example, one test usually has the person count backwards one number to another, such as counting backwards from 86 to 52. Or the officer has the person say the alphabet without singing. These tests are simply made up, as opposed to developed by NHTSA, which developed the three standardized field sobriety tests discussed above. Again, from a scientific point of view, any of these tests have no validity to determine impairment. 

Do Field Sobriety Tests Accurately Show Impairment by Drugs or Alcohol?

There is some scientific evidence that alcohol and certain drugs can increase nystagmus in the eyes. However, we all have some level of nystagmus in our eyes without alcohol or drugs. Nystagmus is a natural occurring event. For example, if you were to have me take the test right now, you would see some twitching of my pupils. 

The problem with the nystagmus test is that there is no baseline for whether the person has nystagmus without alcohol. Let's say a person does the nystagmus test and the officer claims to have counted all possible nystagmus signs. That person could have had nystagmus without alcohol, so we can't say that alcohol caused the nystagmus in that person. This is one reason why the nystagmus test is an unreliable test. 

Nystagmus could have several causes in addition to being a natural event, including lights, fatigue, or prescribed medications. Most importantly, the existence of nystagmus is not evidence that a person is impaired or even affected by alcohol. Nystagmus could be caused by a single drink.

The Walk and Turn test and One-Leg Stand are even less reliable tests for impairment. Frankly put, there is no scientific basis that these tests are indicators of impairment from alcohol or drugs. Our Ann Arbor drunk driving defense attorneys could write about this fact for days but let's put it this way: In testing a driver for impairment, a cop might as well ask the person to throw a football or take a swing at a baseball and judge how the person did. 

Fighting Field Sobriety Tests with the Help of Our Ann Arbor Drunk Driving Defense Attorneys

With this knowledge and understanding of field sobriety tests we are able to attack the police officer's DUI investigation to your advantage. We watch the videos of the investigation very carefully to see how the officer administered the tests. We can take advantage of a situation in which the officer did not give the tests in the right way.

A DUI lawyer must have this level of understanding of Field Sobriety Tests. The prosecutor and cops will put these tests forward as if these are full-proof tests. The National Highway and Safety Administration, the government agency who developed it, has given these tests the aura of authority. A DUI lawyer doesn't challenge the tests will allow the jury to believe the prosecution's claims that these tests are to be believed and accepted. 

At ArborYpsi Law, our Ann Arbor drunk driving defense attorneys are always challenging DUI case. A DUI conviction will go on your record for life and the penalties are harsh. That makes it something to take seriously. It is not enough for a lawyer to do the bare minimum on these cases and tell the client there's nothing to be done on the case. 

Contact us at 734.883.9584, completing our contact form or e-mail us at bernstein@arborypsilaw.com

ArborYpsi Law is located at 4158 Washtenaw Ave., Ann Arbor, MI 48108.