Challenge to admissibility of HGN in DWI

Hall v. State (Unpublished Memo): DWI conviction challenged on grounds that the officer who administered the horizontal gaze nystagmus test to Hall wasn’t an expert in its use.  Under Court of Criminal Appeals authority, the reliability of the HGN test is presumed, leaving the training of the officer who administered the test as the only question.  Emerson v. State, 880 S.W.2d 759, 768-69 (Tex. Crim. App. 1994).  The Tyler court holds that this officer’s “less than scholarly awareness of the recent literature on the subject and his unfamiliarity with any of apparently forty-seven types of nystagmus [i.e, non-DWI causes] goes to the weight of his testimony, not to its admissibility.”

It didn’t help Hall that he denied alcohol use, then admitted it, had alcohol on his breath, was unable to hold his head still, and was generally unsteady on his feet.

Although Mr. Hall fought the law and the law won, expect defense counsel to continue to mount challenges to the HGN.  Why?  Because here’s what the prosecutors have to say about the test:

Nothing is worse for police and prosecutors than impaired drivers who have already been through the system three or four times.These hardcore offenders have learned not to make incriminating statements or take blood alcohol tests. They even practice the standardized field sobriety tests (SFSTs) in bars before they drive home.  Their heightened tolerance to alcohol and repetition of the tests often gives them an ability to display only a small number of impairment clues, but there is one SFST that cannot be practiced or physically controlled—the Horizontal Gaze Nystagmus (HGN) Test.

That is good news for police and prosecutors.  The HGN test is the most accurate of all the tests, the best test for apprehending drivers between .08% and .12%, and the most researched of all the SFSTs. Experience has shown that multiple offenders may be quick to refuse the walk & turn or the one-leg stand tests, but for whatever reasons, many will submit to the HGN test.

The quote is from this 2003 publication of the American Prosecutor’s Research Institute.

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