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Field Sobriety Tests Are Imperfect Indicators of DUI

On Behalf of | Aug 15, 2018 | DUI & Traffic Defense |

The Standardized Field Sobriety Test (SFST) was developed in the 1970s to assess the impairment of drivers through the administration of three tests. These tests are the Walk and Turn (WAT), the One Legged Stand (OLS), and the Horizontal Gaze Nystagmus (HGN). Though the three tests run together give an officer a strong indication if a subject is impaired, there are a variety of reasons that the SFST is an imperfect test that can lead officers to mistakenly charging safe drivers with Driving Under the Influence.

There are drivers with physical conditions that may make the Walk and Turn or One Legged Stand difficult to perform. The Horizontal Gaze Nystagmus has officers observing the eyes for slight twitches that can indicate that a subject is under the influence. However, some drivers may suffer from eye conditions that prevent them from smoothly following an object that could mistakenly indicate to an officer that they are impaired.

study in 1998 found the all three tests performed together have an 88% chance of indicating that a driver is impaired. While this is a good indication, it is not perfect. It’s a B+. There are instances in which Illinois clients pass these tests, only to be charged with DUI anyway.

For example, a client was driving in the early morning hours when he was stopped by a police officer for an improper lane violation. Essentially, our client was adjusting Spotify on his phone and he crossed over the dotted white lines. He was not speeding or driving erratically. The client was honest and admitted that he had drank three beers about two hours earlier at a party.

The officer requested that he step out of the vehicle and submit to SFSTs. Our client complied and performed adequately on the Walk and Turn and One Legged Stand tests designed to determine if someone is impaired.

Then, the Horizontal Gaze Nystagmus was administered. The police officer claimed that our client did not perform acceptably in the HGN. This test cannot be viewed on Body-Cam or Dash-Cam because the officer is trying observe slight twitching of the eyes.

Though our client performed the two physical tests sufficiently, the officer claimed that our client had “failed” the SFSTs and transported him to the police station where he requested that he submit to a chemical breath test. Again, our client complied and produced a Blood Alcohol Concentration (BAC) of .035. Despite the fact that he denied consuming any drugs and there was no evidence of a drug use, the officer still charged our client with Driving Under the Influence.

We were able to assist this client in getting this case dismissed. Under Illinois law, a person will not suffer a license suspension for DUI if they submit to a chemical test (blood, breath, or urine) if they are under the legal limit of .08. As this was the case, our client’s license was not suspended.

Additionally, the case was dismissed by the State’s Attorney’s Office because under Illinois law if a person has a BAC of .05 or less at the time he committed the alleged offense of DUI that person is presumed “not under the influence of alcohol.” Therefore, the State’s Attorney’s office acted justly and dismissed the case.

If you suffer an unfair DUI charge, we strongly encourage you to contact Richard Fenbert at Fenbert & Associates, LLC, so that he can assist you in avoiding a suspended license.