The HGN test is used by an increasing number of law enforcement agencies across the country as an additional means to determine probable cause as to whether a person is operating a vehicle under the influence of alcohol.
According to a test manual devised by the United States Department of Transportation for use by law enforcement agencies, the HGN test is the single most accurate field test to use in determining whether a person is alcohol impaired. U.S. Department of Transportation, National Highway Safety Administration, Improved Sobriety Testing (1984) 4.
The HGN test is relatively easy to administer. The driver taking the HGN test usually is asked to focus on a “stimulus” (such as a pen) held in an officer’s hand at the driver’s eye level approximately six to eight inches away. The officer will then move the stimulus gradually out of the driver’s field of vision toward the driver’s ear. Because it has been shown that the onset of the angle of nystagmus at less than forty-five degrees indicates the presence of alcohol, the officer watches each eye to determine whether nystagmus occurs at an angle less than forty-five degrees. See State v. Superior Court (1986),
According to the test manual devised by the United States Department of Transportation, an officer administering the HGN test observes the driver’s eyes to detect the following three signs of intoxication:
“(1) The jerking of the eyes occurs much sooner. That is, the more intoxicated a person becomes, the less that he has to move his eyes to the side in order for the jerking to occur.
“(2) If you have a suspect move his eyes as far to the side as possible, you can estimate in a general way the extent of intoxication. The greater the alcohol impairment, the more distinct the nystagmus will be in the extreme gaze position.
“(3) If the suspect is intoxicated, he cannot follow a slowly moving object smoothly with his eyes.” Improved Sobriety Testing, supra, at 3.
A person may receive up to six points on the HGN test. Specifically, each eye is tested to determine (1) whether the angle of onset of nystagmus is less than forty-five degrees; (2) whether nystagmus, when the eye is moved as far as possible to one extreme, is moderate or distinct; and (3) whether the eye can follow a moving object smoothly. A score of four or more points indicates a BAC level above .10 percent. Using these criteria, an officer should be able to correctly determine seventy-seven percent of the time whether a person taking the test is under the influence of alcohol or sober. When the HGN test is used in conjunction with the walk-and-tum field sobriety test, an officer’s ability to detect whether a driver is under the influence of alcohol is improved. See Improved Sobriety Testing, supra, at 4.
In the instant case, appellee had objected to Trooper Click’s testimony regarding the HGN test. The trial court overruled this objection, stating that the test had been accepted by the courts.
The court of appeals found that admission of Trooper Click’s testimony about the HGN test was improper
This court has not previously addressed this issue. However, the appellant argues that a properly trained law enforcement officer is competent to testify as to a person’s performance of the HGN test without expert testimony to establish the scientific foundation of the test. A review of courts of appeals decisions in this state on this issue establishes that a majority of appellate courts has admitted testimony by law enforcement officers concerning this test. The appellate courts generally have held that the HGN test is similar to other field sobriety tests and is admissible without expert testimony. See, e.g., State v. Nagel, supra; State v. Welday (Sept. 27, 1989), Medina App. No. 1793, unreported; State v. Brug, supra; State v. Earley, supra; State v. Hintz, supra; State v. Lewis (Apr. 29, 1986), Seneca App. No. 13-84-21, unreported.
There is a split of opinion in other states concerning this issue. Some jurisdictions have held that the HGN test is a scientific test, which requires expert testimony regarding the test’s scientific reliability and acceptance. See, e.g., State v. Barker (W. Va. 1988),
In State v. Superior Court, supra, the Supreme Court of Arizona held that “* * * in the hands of a trained officer the [HGN] test is reasonably trustworthy and may be used to help establish probable cause to arrest. ***” Id. at 276,
We find that the HGN test has been shown to be a reliable indicator of BAC levels. Accordingly, results of this test are admissible so long as the proper foundation has been shown both as to the officer’s training and ability to administer the test and as to the actual technique used by the officer in administering the test.
In this case the evidence shows that such a foundation was established. Trooper Click testified that he had received five days of training regarding the HGN test and described the methods he used in testing and evaluating appellee’s performance on the HGN test. His testimony concerning what he looked for when administering the test corresponds to the testing methods devised by the United States Department of Transportation. Trooper Click testified that:
“The horizontal gaze nystagmus and the lateral horizontal gaze nystagmus is [sic] used to refer to a test in which a person’s eyes are observed following stimulus, either a penlight, flashlight, ballpoint pen, any type of object, even a finger.
“In this test, a person is asked to hold their head steady. They’re asked to watch an object, which is held approximately six to eight inches in front of them. I personally always use a ballpoint pen.
“The pen is held up in front of them. They are asked to watch the object, follow the object as it moves in a horizontal fashion without moving their head, only moving their eyes.
il * * *
“We were trained to watch for three characteristics when giving this test. The three things we’re looking for is [sic] known as distinct nystagmus prior to 45 degrees. That is the approximate point of 45 degrees where you begin to see a jerky motion, a side-to-side motion of a person’s eye.
“We’re also trained to look for distinct nystagmus at maximum deviation.
U* * *
“What that means is, the point where a person can look farthest to the side, moving their eyes only, not their head. That is considered maximum deviation, as far from the middle as a person can look.
“We’re looking for a distinct nystagmus or a distinct jerky motion of the eye at that point.
U* * *
“We have been instructed and trained * * * that a person who has consumed alcohol will exhibit these signs, as well as a lack of what we call smooth pursuit.
ÍÍ* * *
“The smooth pursuit is the ability of the eye to follow an object in a smooth, fluid motion.
“We have been instructed, and I have observed, persons who have consumed alcohol, instead of following the object in a smooth, fluid motion, their eyes move like they’re clicking along, just at intervals.”
When asked specifically about appellee’s performance on the HGN test, Trooper Click testified:
“Mr. Bresson was sitting in the front seat of the patrol car with me. He was not handcuffed. I held the ball*129 point pen. * * * I held it up in front of Mr. Bresson, asked him if he could see the very end of it. I asked him to follow the pen in a horizontal fashion, side to side, without moving his head.
He He
“Of the six points we were looking for, Mr. Bresson exhibited all six points: The lack of smooth pursuit, the distinct nystagmus prior to 45 degrees, and distinct nystagmus at maximum deviation.”6
The trial court has broad discretion in admitting evidence based on scientific processes. See United States v. Traficant (N.D. Ohio 1983),
Although not an issue in the instant case, we hasten to add that although results on an HGN test may be admissible at trial by a properly trained officer, such an officer may not testify as to what he or she believes a driver’s actual or specific BAC level would be, based solely on the HGN test results. “* * * Such a use of HGN test results would raise a number of due process problems different from those associated with the chemical testing of bodily fluids. The arresting officer’s ‘reading’ of the HGN test cannot be verified or duplicated by an independent party. * * * The test’s recognized margin of error provides problems as to criminal convictions which require proof of guilt beyond a reasonable doubt. The circumstances under which the test is administered at roadside may affect the reliability of the test results. Nystagmus may be caused by conditions other than alcohol intoxication. And finally, the far more accurate chemical testing devices are readily available.” State v. Superior Court, supra, at 279,
The judgment of the court of appeals is reversed and the judgment of the trial court is reinstated.
Judgment reversed.
Notes
However, horizontal gaze nystagmus can occur for reasons other than ingestion of alcohol. Some of these reasons are seizure, medications, phencyclidine (“PCP”), barbiturates and other depressants. Additionally, a large disparity between test results of the right and left eyes may indicate brain damage. See Improved Sobriety Testing, supra, at 4.
In a laboratory test, four hundred forty-one subjects had BAC levels ranging from 0.10 to 0.19 percent. Their performance on three sobriety field tests — the gaze nystagmus test, the walk-and-turn test, and the one-leg stand test — was scored by police officers. The gaze nystagmus test was shown to be the most accurate single test in determining whether a person’s alcohol concentration was above or below 0.10 percent. The accuracy of these tests were: gaze nystagmus, seventy-seven percent; walk-and-turn, sixty-eight percent; one-leg stand, sixty-five percent; and combined gaze nystagmus and walk-and-turn, eighty percent.
Additionally, a field evaluation was performed by using police officers who stopped more than one thousand five hundred drivers for suspicion of driving while under the influence. The evaluation showed the following accuracy ratings: gaze nystagmus, eighty-two percent; walk-and-turn, eighty percent; one-leg stand, seventy-eight percent; and combined gaze nystagmus and walk-and-turn, eighty-three percent. Improved Sobriety Testing, supra, at 1. See, also, U.S. Department of Transportation, National Highway Traffic Safety Administration, Alcohol and Highway Safety 1984: A Review of the State of the Knowledge (1985) 55-56.
It has been stated that the HGN test is especially useful in detecting drivers who have a BAC level between 0.10 and 0.14 percent. Frequently, traditional field sobriety tests are not sensitive enough to detect a driver who has a BAC level below .14 percent. See State v. Superior Court, supra, at 272,
“Gaze nystagmus testing is a field sobriety test that cannot be controlled voluntarily by the suspect. * * *” Good & Augsburger, supra, at 469.
The court in State v. Superior Court, supra, at 279,
Trooper Click also administered four other field sobriety tests. As to appellee’s performance on the one-leg stand test, Trooper Click stated that appellee swayed from side to side and put his foot down once. Trooper Click further testified that while performing the walk-and-tum test, appellee once stopped in order to regain his balance and lost his balance when turning around. Appellee was able to do the finger-to-nose test, but swayed from side to side while doing it. Appellee also recited the alphabet correctly, albeit with some slurring in his speech.
