New Illinois Supreme Court Case - The HGN Test Is Not All It's Been Touted to Be

The Supreme Court of Illinois  in The People of the State of Illinois v. Joanne Mckown last week issued an opinion regarding the Horizontal Gaze Nystagmus (HGN) field sobriety test and made some remarkable findings. 

First, the Court held that the HGN test can not be used to show actual loss of the normal use of mental or physical faculties, but instead, can only be used to show that a "defendant may have consumed alcohol and may, as a result, be impaired."  There is no more of this, "they failed the HGN so they are therefore intoxicated" arguments.

Second, the Court held that just because a scientific test is regularly relied upon in law enforcement does not make it admissible in court.  The test is whether the particular test is relied upon in the scientific community, not the law enforcement community. 

Third, just because a test meets the standards for admissibility under Frye, that does not preclude the trial court from conducting a balancing test  and deem the evidence "inadmissible on grounds of undue prejudice."

Finally, the Court held that the test must strictly comply with the NHTSA standards for performing the test.  This means the cops aren't going to be allowed to come in a testify, "I did it the way I was trained to do it."  They are going to be held to the standard of the NHTSA.

Here's hoping the Texas Court of Criminal Appeals will at least read this opinion.  Even more importantly, here's hoping that the trial courts in Texas will read the case and understand that they truly are gatekeepers for the admission of evidence.

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Brad Walters - July 9, 2010 7:32 PM

There is a NHTSA study called "The Robustness of HGN" published on the NHTSA website. It purports to prove that it does not matter if the officer moves the stimulus to quickly or positions the stimulus incorrectly. While the data shows that this is true it also shows that 4-6 HGN clues are present frequently in subjects under .05 to .02. It is good for cross of an "expert" who state that HGN would not be present unless they were over .08. Check it out.

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