Opinion ID: 2114349
Heading Depth: 1
Heading Rank: 11

Heading: Limits on Admission of HGN Evidence at Trial

Text: Defendant argues that the use of HGN evidence should be limited to use at a preliminary hearing to establish probable cause to arrest. She argues that the HGN test is not sufficiently reliable to be used as evidence of guilt because it does not prove impairment beyond a reasonable doubt. Defendant cites no authority for imposing such a limitation but urges this court, as gatekeeper of evidence, to declare that HGN test results may not be used at trial. Defendant overlooks the threshold requirement of relevance. Each individual item of evidence does not have to prove the fact at issue beyond a reasonable doubt. Rather, each individual item of evidence must tend to show that the fact at issue, in this case impairment due to alcohol, is more or less likely. By way of analogy, it is often said that `a brick is not a wall.' Fed. R. of Evid. 401, Advisory Committee's Note, quoting C. McCormick, Handbook of the Law of Evidence § 152, at 317 (1954). That is, an individual item of evidence is merely a brick, one of many bricks used to build the wall that is the fact at issue. The police officer's testimony regarding the results of a defendant's failed HGN test tends to show that he or she consumed alcohol prior to being tested. Similarly, testimony that a defendant did not display any sign of HGN is relevant evidence that tends to show that he or she had not consumed alcohol. The result of the test, therefore, makes it either more or less likely that a defendant was impaired due to alcohol. This is the concern addressed by the trial court's conclusion that the use of HGN evidence should be limited to proof of alcohol consumption and the possibility of resulting impairment. Limitation may take the form of sustaining an objection to certain questions or arguments made by the prosecutor, giving a limiting instruction at the time the testimony is given, or giving a written jury instruction at the conclusion of the case. The need for a limitation on the use of the evidence, however, is not a basis for finding the evidence inadmissible at trial under the test of Frye. We, therefore, reject defendant's invitation to limit the use of this relevant piece of evidence to showing probable cause. Defendant also argues that despite its relevance, a failed HGN test result proves too much because of its aura of scientific certainty. In effect, she is arguing that the risk of undue prejudice from this evidence substantially outweighs its probative value. See People v. Walker, 211 Ill.2d 317, 337, 285 Ill.Dec. 519, 812 N.E.2d 339 (2004) (Illinois courts have long recognized, as a matter of common law, that a trial court may exercise its discretion to exclude evidence, even when it is relevant, if its prejudicial effect substantially outweighs its probative value). This balancing of risk of prejudice versus probative value is not performed across the board. It is necessarily a case-by-case analysis. Our finding that HGN evidence meets the Frye standard does not preclude the possibility that, in a given case, the trial court might rule such evidence inadmissible on grounds of undue prejudice. Defendant also asserts that there is insufficient oversight of police officers who administer the HGN test in the field, particularly with regard to their qualifications and their ability to interpret the test results. She argues that field studies and anecdotal evidence suggest that the vast majority of police officers improperly perform the test in arrest situations. In light of this, she argues for more extensive training of police officers and for stricter standards regarding the procedure for performing the test in the field. Specifically, she claims that if HGN evidence does meet the Frye standard, the only acceptable method for administering the HGN test by a police officer is the NHTSA method. This argument merges two separate questions: first, the proper method for conducting HGN testing in the field and, second, the qualifications of the witness who will testify regarding the HGN test results. The trial court framed the question before it on remand in terms of the general acceptance of the NHTSA roadside HGN test. The evidence presented by both parties was geared toward the test as developed and taught by the NHTSA. Thus, the trial court's ruling on the Frye issue necessarily imported the NHTSA standard testing protocol. Our adoption of the trial court's conclusion is similarly limited. We hold that evidence of HGN field-sobriety testing, when performed according to the NHTSA protocol by a properly trained officer, is admissible under the Frye test for the purpose of showing whether the subject has likely consumed alcohol and may be impaired. As for the qualifications of the individual witness, the trial court concluded that a proper foundation must be laid, including a showing that the witness is properly trained and that he performed the test in accordance with proper procedures. We agree. A properly trained police officer who performed the HGN field test in accordance with proper procedures may give expert testimony regarding the results of the test. We also agree with the trial court's conclusion that a testifying officer may use the HGN test results as a part of the basis for his opinion that the defendant was under the influence and impaired. In sum, we affirm each of the trial court's five conclusions of law.