When May Evidence of HGN Come on Down . . . or In?

The question I am most frequently asked these days is some version of the following:

May a law enforcement officer trained in administering the HGN test testify at trial about a defendant’s performance on the test if no other expert testifies about the relationship between nystagmus and impairment by alcohol?

While the answer obviously is either yes or no, there is more than one way to analyze the issue. Since today is Thursday, I’m going to throw it back to Bob Barker and the Price is Right and give you two showcases to consider.

Showcase No. 1. This one is for our first contestant, the assistant district attorney.

The answer. The legislature has already answered this question, and the answer is yes.

The analysis.  After the North Carolina Supreme Court held in State v. Helms, 348 N.C. 578 (1998), that the HGN test was a scientific test that required a proper foundation to be admissible, the General Assembly enacted Rule 702(a1) of the North Carolina Rules of Evidence to permit a witness “qualified under subsection (a) of this section and with proper foundation” to “give expert testimony solely on the issue of impairment and not on the issue of specific alcohol concentration level relating to . . . the results of a Horizontal Gaze Nystagmus (HGN) Test when the test is administered by a person who has successfully completed training in HGN.” See S.L. 2006-253, § 6; S.L. 2007-493, § 33. The court of appeals in State v. Smart, 195 N.C. App. 752 (2009) interpreted Rule 702(a1) “as obviating the need for the State to prove that the HGN testing method is sufficiently reliable.” Id. at 756.Thus, Smart determined that the trial court did not err in admitting HGN testimony from an officer trained in administering the test.

While Rule 702(a) was amended in 2011 to incorporate the reliability standard from Daubert v. Merrell Dow Pharmaceuticals, 509 U.S. 579 (1993), Rule 702(a1) was not amended. Thus, it continues to reflect the legislature’s assessment that HGN testing is sufficiently reliable as a basis for expert testimony.

Showcase No. 2. This one is for our second contestant, the assistant public defender.

The answer. Smart did not survive the adoption of Daubert, and a law enforcement officer who is trained in HGN but has no scientific expertise cannot establish the requisite foundation for the admission of the testimony.

The analysis.  Rule 702(a1) requires that a witness be qualified under Rule 702(a) and that a proper foundation be established for admission of HGN testimony. The cross-reference to subsection (a) means that the foundational requirements for scientific testimony such as HGN changed in 2011. Thus, Smart, which interpreted the requirements under former Rule 702(a) no longer controls. The court of appeals recently hinted at this possibility, noting in State v. Godwin, __ N.C. App. ___, 786 S.E.2d 34 (2016),  that “[w]hile some may even question whether Smart survives the amendment to Rule 702(a), that issue is not the one presently before us.” Id. at __; 786 S.E.2d at 38.  Indeed, Godwin characterized Rule 702(a1) as a limitation on the admissibility of expert testimony, rather than a loosening of admissibility standards, stating that, pursuant to subsection (a1) an expert witness may testify “solely on the issue of impairment and not on the issue of specific alcohol concentration,” and the HGN test must have been “administered by a person who has successfully completed training in HGN.” Id. at __; 786 S.E.2d at 37 (2016).

Under current Rule 702(a), expert testimony, including expert testimony about HGN, must be based on sufficient facts or data and must be the product of reliable principles and methods. A law enforcement officer’s training in HGN testing does not equip him to explain the physiological relationship between the impairment by alcohol and HGN clues. If a law enforcement officer is not qualified to testify about the scientific basis for HGN testing, then the officer cannot establish that the test results are admissible. See State v. Torres, 976 P.2d 20, 32 (N.M. 1999).

In (modified) Price is Right tradition, go ahead and estimate the likelihood that our appellate courts will adopt either showcases’ reasoning.

Of course, these aren’t the only two ways of analyzing the issue.

A judge who agrees that Smart does not survive the amendment of Rule 702 might nevertheless find the law enforcement officer’s HGN testimony admissible.

  • She might conclude that she can take judicial notice of the causal connection between HGN and alcohol consumption pursuant to Rule 201.


See, e.g., United States v. Horn, 185 F. Supp.2d 530, 555 (2002) (finding this connection so well established that it is appropriate to be judicially noted); State v. Taylor, 694 A.2d 907, 911 (Me. 1997) (“The scientific studies, law review articles, and other literature on the subject of HGN testing, as well as the case law, demonstrate that the HGN test is reliable if an officer properly administers it.”). But see People v. McKown, 875 N.E.2d 1029, 1046 (Ill. 2007) (concluding that technical writings about HGN testing “reveal a dichotomy in the scientific community, rather than the unequivocal or undisputed viewpoint necessary for us to take judicial notice. . . . of the general acceptance of the HGN test as a reliable indicator of alcohol impairment”); State v. Witte, 836 P.2d 1110, 1121 (Kan. 1992) (“The reliability of the HGN test is not currently a settled proposition in the scientific community.”); Torres, 976 P.2d at 33 (determining that “judicial notice of the evidentiary reliability of HGN testing would be inappropriate at this time”).

  • She might conclude that the foundation testimony necessary to attribute HGN clues to impairment from alcohol can be provided by a law enforcement officer with specialized training.


See State v. Ruthardt, 680 A.2d 349, 362 (1996) (“The foundation testimony need not come from a scientific or medical expert; testimony from a Delaware police officer with specialized training in HGN will suffice.”). But see Horn, 185 F. Supp.2d at 555 n.44 (“[A] police officer is unlikely to have the qualifications needed to testify under Rule 702 as to the scientific principles underlying the HGN test or as to whether there is a causal link between alcohol use and exaggerated nystagmus.”)

  • She might conclude that the officer’s experience in administering the HGN test and subsequently viewing chemical testing results, combined with his training, render the officer an expert on the correlation between HGN and impairment.


Cf. State v. Hullinger, 649 N.W.2d 253 (N.D. 2002) (recounting officer’s testimony that he had administered the HGN test 50 times and that he had not observed anyone fail the test who registered less than a 0.10 percent blood alcohol concentration).

It seems likely that, whatever analysis state trial courts adopt, our appellate courts soon will be called upon to clarify this issue. I, for one, can’t wait.

Court of appeals, come on down!