Supreme Court Sends DUI Case Back to Orange County Court

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Police stopped William Leahy for driving 55 in a 25-mile-per-hour zone.  According to the officer, “Leahy’s face was flushed, his eyes were red and watery, his speech was slurred, his balance was unsteady, and he exuded the odor of alcohol.”


“Leahy took the HGN test. “Nystagmus is an involuntary rapid movement of the eyeball, which may be horizontal, vertical, or rotary. An inability of the eyes to maintain visual fixation as they are turned from side to side (in other words, jerking or bouncing) is known as horizontal gaze nystagmus, or HGN.”

The officer believed Leahy failed the HGN test and arrested him.  The intoxilyzer breath test showed a .10 percent blood-alcohol level.  The Orange County DA charged Leahy with driving under the influence of alcohol and driving with a blood-alcohol concentration of .08 percent or higher.

Leahy’s DUI Defense Attorney filed a motion to exclude evidence of the HGN test result based on People v. Kelly (1976) 17 Cal.3d 24; Frye v. United States (D.C. Cir. 1923) 293 F. 1013, 1014.

The Orange County trial judge denied the motion.

The judge reasoned “the Kelly-Frye rule does not apply because the nature of the HGN test isn’t a specific test for the determination of alcohol; it is only a symptom that the officer is testifying to … in the same manner as he might be testifying to a symptom of slurred speech or a person’s face turning red, or … bloodshot eyes. It would be on that type of reasoning that it would be allowed in.”


The Court of Appeal reversed the trial judge and agreed with the analyses of People v. Williams (1992) 3 Cal.App.4th 1326, 1332-1335 and People v. Loomis (1984) 156 Cal.App.3d Supp. 1, 5-7 and concluded [i]t was error to admit HGN evidence as either lay or expert testimony without a Kelly-Frye foundation, i.e., proof of general acceptance of HGN in the scientific community.


Mr. Leahy found himself in the California Supreme Court. This court concluded, “the Court of Appeal correctly decided that the HGN test was a ‘new scientific technique’ within the scope of the Kelly formulation, and for that reason, proof was required of its general acceptance by the scientific community.”

The Supreme Court disagreed with the Orange County DA’s argument that HGN testing is neither “new” nor “scientific.”

As for whether HGN is scientific, the Court cited People v. Stoll (1989) 49 Cal.3d 1136, where the Court said by reason of the potential breadth of the term “scientific” in the Kelly/Frye doctrine, the courts often refer “to its narrow ‘common sense’ purpose, i.e., to protect the jury from techniques which, though ‘new,’ novel, or ‘ “experimental,” ‘ convey a ‘ “misleading aura of certainty.”

The Court found it unmistakable that a jury could be unduly and unjustifiably impressed by “the “aura of certainty” emanating from the officers’ description of HGN tests.“

Mr. Leahy’s case was sent back to the trial court in Orange County for a Kelly hearing to determine whether the HGN evidence is admissible.  Depending on the outcome of that hearing, the judgment could be reinstated or a new trial could be ordered.

The citation for this opinion is People v. Leahy (1994) 8 Cal. 4th 587.

If arrested for DUI, contact the Law Office of Richard Wagner for a FREE Consultation – (714) 721-4423.

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