Cases in Controversy
| Publication year | 1997 |
| Pages | 24 |
Salt Lake City v. Garcia: A Scientific Evidence Decision Built Upon Sand
Ralph Dellapiana, J.
Introduction
On the unusual date of February 29, 1996, the Utah Court of Appeals made a peculiar ruling in Salt Lake City v. Garcia'[1]-a case of first impression in Utah regarding the foundational requirements for scientific evidence. At issue was the admissibility of the horizontal gaze nystagmus (HGN) test, a "field sobriety test" often used in DUI cases. Although the Garcia court did not rule clearly on the issue, the majority of jurisdictions have found the HGN test to be "scientific" in nature.[2]
The Garcia decision is significant because it allows Utah juries to consider this scientific evidence without first requiring the proponent to establish a foundation that the science is inherently reliable. In fact, the trial court judge admitted the HGN evidence despite specifically finding that the city was unable to establish a foundation that the evidence admitted against the defendant was either inherently reliable, or generally accepted.[3] This is important because, prior to Garcia, the foundational showing did not go just to the weight of evidence, but was a prerequisite to admissibility.[4]
Thus, the Garcia decision may have created a shortcut to the admission of scientific evidence: one need only argue that one's scientific evidence (or one's voodoo masquerading as science) is simply "not presented as scientific evidence." Without further ado, the jury gets to hear it.
The dubious prudence of this precedent forebodes a potential flood of scientific evidence that may be more easily admitted now that no foundation is required as to its reliability. Garcia has especially ominous implications for criminal defendants facing prosecution using "experts" asserting the defendants' guilt based on unreliable theories. The crucial question is: should the house built on this rickety precedent stand? In other words, is Garcia good law, or should a prior foundation of reliability still be a prerequisite for the admission of scientific evidence?
The Horizontal Gaze Nystagmus Test
Imagine yourself in the following scenario:
Your eyes are being tested. As the tester moves a stimulus (such as a bright penlight) across your field of vision, your eyes bounce or jerk in a stop-and-go motion as you attempt to follow the stimulus. The tester notes that this jerking begins before your eyes deviate to a forty-five degree angle, and, when you move your eyes as far as possible to one side, the jerking is fairly distinct.
You wonder what it means. According to the Salt Lake Police Department, the test means you have a blood alcohol content of at least . 10 grams per deciliter.[5] If the test were performed while you were driving a car, the test could be used as evidence that you were driving your vehicle with a blood alcohol content over the legal limit of .08. This "bouncing-eyeball" test is. officially known as the Horizontal Gaze Nystagmus or HGN test.
"Nystagmus" is one of several types of abnormal ocular movements defined as "an involuntary rapid movement of the eyeball, which may be horizontal, vertical, rotary, or mixed."[6] The theory behind the gaze nystagmus test is that there is a correlation between the amount of alcohol a person consumes and the angle of onset of the nystagmus.[7]
When conducting the HGN test, the officer is told to look for three indicators in each eye: (1) angle of onset occurring before forty-five degrees in each eye; (2) ability of the eye to follow the moving object smoothly; and (3) the presence of moderate or distinct nystagmus at maximum deviation. If the officer finds four of the possible six clues, then he can purportedly classify the suspect's blood alcohol content as above . 10 percent.[8]
The HGN Test Requires a Foundation
Whatever legitimacy the HGN test may have is clearly based on scientific principles. A foundational showing of the test's underlying principle is necessary because the alleged causal link between bouncing eyeballs and having a blood alcohol content above .10 percent is beyond the understanding of lay jurors.[9] The additional step allegedly connecting a positive HGN test result with the ability to safely operate a motor vehicle similarly exceeds lay comprehension. In addition, the mechanics of the HGN test, unlike those of other field sobriety tests (e.g. one-leg stand, walk and turn), are not within the common knowledge of lay jurors.[10]
Furthermore, the methodology of the HGN field test is fraught with fallibility. First, the failure to use any device to measure the critical angles leads to inconsistent and inaccurate results[11]Moreover, there is disagreement among authorities as to what is the correct angle of onset. For example, according to one authority, fifty to sixty percent of sober individuals who deviate their eyes more than forty degrees to the side will exhibit nystagmus, and this nystagmus cannot be distinguished from alcohol gaze nystagmus.[12]
Second, no device is used to keep the test subject's head still during the test. Head movement affects the officer's estimation of angle of onset, thus affecting the result of the test.[13]
Third, nystagmus has causes other than alcohol consumption: nystagmus is caused by some illnesses and by substances other than alcohol, and some people in the population exhibit natural nystagmus.[14]
Fourth, the test as typically performed on the street in the dark without measurements or any recording device, is not verifiable by independent means. There is no way to review and confirm or refute the officer's subjective observations; thus the roadside test is prone to abuse.
In summary, the field-administered HGN test is simply not an inherently reliable method of measuring gaze nystagmus. Moreover, the test's purported ability to prove alcohol intoxication is not clear. Further, as the alleged connection between gaze nystagmus and blood alcohol content is beyond the understanding of lay jurors, HGN evidence has the potential to mislead jurors.
Consequently, Utah courts considering the admissibility of HGN evidence should reject the Garcia court's approach and apply Utah's "inherent reliability" standard. The required foundation necessarily would address both the scientific principle underlying the test and the methodology for administering the test.
Why a Foundation Is Necessary
There are good reasons for requiring foundation in scientific evidence cases. The foundation separates scientific wheat from chaff. This is important because the prejudicial effect of erroneously admitted evidence is greater when scientific...
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