Scientific Evidence Standards in DUI / DWI Cases


By Donald J. Ramsell

"In determining whether scientific evidence is admissible, the trial court is to make sure that the decision by the trier of fact is based on scientific facts, not science fiction." State v. O'Key, 321 Or. 285, 899 P.2d 663 (1995)


In DUI cases, the scientific testing of blood, breath, or urine, or the so-called 'scientific' filed sobriety tests, has a critical effect on the outcome of a trial. Evidence perceived by lay jurors to be scientific in nature possesses an unusually high degree of persuasive power. The function of the court is to ensure that the persuasive appeal is legitimate. The value of proffered expert scientific testimony critically depends on the scientific validity of the general propositions utilized by the expert. See John William Strong, Language and Logic in Expert Testimony: Limiting Expert Testimony by Restrictions of Function, Reliability, and Form, 71 Or.L.Rev. 349, 361 (1992) (explaining this concept). Such scientific assertions, therefore, should be supported by the appropriate scientific validation. Id. at 368. This approach "ensure[s] that expert testimony does not enjoy the persuasive appeal of science without subjecting its propositions to the verification processes of science." Id.

The admissibility of certain evidence in DUI cases has been the subject of great dispute. In a DUI case, like every other criminal case, the admissibility of evidence is governed by the ordinary rules of evidence, i.e. relevance and materiality. However, evidence which is considered to be 'scientific, technical, or the product of other specialized knowledge' (hereinafter referred to as 'scientific') must meet certain additional legal standards before it can be admitted at trial.

There are three basic areas where defendants have challenged the admissibility of evidence as improper scientific evidence - sobriety tests, opinion testimony, and chemical test methods (i.e. breath, blood or urine tests)

This chapter will discuss the basic law governing the admissibility of scientific evidence in DUI cases.

What constitutes 'scientific' evidence?

Scientific evidence is the product of scientific tests or studies. Evidence labeled "scientific" carries a greater weight in the eyes of the jury, which may accord it undue significance because "science" is equated with truth. M. Udall & J. Livermore, Law of Evidence § 102 (2d ed.1982). People v. McKown 226 Ill.2d 245, 254, 875 N.E.2d 1029, 1035, 314 Ill.Dec. 742, 748 (Ill.,2007)

A more detailed examination of how courts have determined whether evidence is 'scientific' is embodied in the Daubert decision, as well as Federal Rule 702, upon which Daubert was decided:

The primary locus of this obligation is Rule 702, which clearly contemplates some degree of regulation of the subjects and theories about which an expert may testify. "If scientific, technical, or other specialized knowledge will assist the trier of fact to understand the evidence or to determine a fact in issue" an expert "may testify thereto." (Emphasis added.) The subject of an expert's testimony must be "scientific ... knowledge." The adjective "scientific" implies a grounding in the methods and procedures of science. Similarly, the word "knowledge" connotes more than subjective belief or unsupported speculation. The term "applies to any body of known facts or to any body of ideas inferred from such facts or accepted as truths on good grounds." Webster's Third New International Dictionary 1252 (1986). Of course, it would be unreasonable to conclude that the subject of scientific testimony must be "known" to a certainty; arguably, there are no certainties in science. See, e.g., Brief for Nicolaas Bloembergen et al. as Amici Curiae 9 ("Indeed, scientists do not assert that they know what is immutably 'true'-they are committed to searching for new, temporary, theories to explain, as best they can, phenomena"); Brief for American Association for the Advancement of Science et al. as Amici Curiae 7-8 ("Science is not an encyclopedic body of knowledge about the universe. Instead, it represents a process for proposing and refining theoretical explanations about the world that are subject to further testing and refinement" (emphasis in original)). But, in order to qualify as "scientific knowledge," an inference or assertion must be derived by the scientific method. Proposed testimony must be supported by appropriate validation- i.e., "good grounds," based on what is known. In short, the requirement that an expert's testimony pertain to "scientific knowledge" establishes a standard of evidentiary reliability.

Daubert v. Merrell Dow Pharmaceuticals, Inc. 509 U.S. 579, 589, 113 S.Ct. 2786, 2795 (U.S.Cal.,1993)(footnotes omitted)

A "Scientific method" is a validation technique consisting of the formulation of a hypothesis, followed by an observation of experimentation to test the hypothesis. Id., 509 U.S. at ----, 113 S.Ct. at 2796-97, 125 L.Ed.2d at 483. Therefore, whenever a litigant claims that a particular scientific technique or theory is valid, for purpose of introducing expert testimony regarding the scientific knowledge derived therefrom, empirical verification is required. Id.; see also State v. O'Key, 321 Or. 285, 899 P.2d 663 (1995)(admissibility of HGN test)

Basic legal standards controlling the admissibility of scientific evidence - Frye and Daubert

Once a type of evidence is considered to be 'scientific', the courts must then determine whether the method or process involved in obtaining the evidence is reliable or admissible. There are two basic theories by which most state courts determine whether evidence meets such a standard and is hence admissible - the Frye standard and/or the Daubert standard. A few others have adopted their own admissibility tests.

The following is a compilation by American Law Reports as to which standards are being used by state courts governing the admissibility of scientific evidence:

Source: Alice B. Lustre, J.D, American Law Review "Post-Daubert Standards for Admissibility of Scientific and Other Expert Evidence in State Courts", 90 ALR 453 (5th Ed. 2001: online edition updated weekly)

The Frye Standard

The notion of a special rule for scientific evidence originated in 1923 in Frye v. United States, 293 Fed. 1013 (D.C.Cir.1923). K. Broun, McCormick on Evidence § 203, "Scientific tests in general: admissibility and weight" (6th ed.2006). Frye was a murder prosecution in which the trial court rebuffed defendant's effort to introduce results of a "systolic blood pressure test," a forerunner of the polygraph. On appeal, the Court of Appeals for the District of Columbia imposed a new standard of admissibility for scientific evidence:

Just when a scientific principle or discovery crosses the line between the experimental and demonstrable stages is difficult to define. Somewhere in this twilight zone the evidential force of the principle must be recognized, and while courts will go a long way in admitting expert testimony deduced from a well-recognized scientific principle or discovery, the thing from which the deduction is made must be sufficiently established to have gained general acceptance in the particular field in which it belongs. Frye v. United States, 293 Fed. at 1014 (D.C.Cir.1923).

The standard expressed in Frye v. United States; commonly called the "general acceptance" test, dictates that scientific evidence is admissible at trial only if the methodology or scientific principle upon which the evidence is based is sufficiently established to have gained general acceptance in the particular field in which it belongs. Bernardoni v. Industrial Com'n, 840 N.E.2d 300 (Ill. App. Ct. 3d Dist. 2005).

The Frye standard does not demand unanimity, consensus, or even a majority to satisfy the general acceptance test, and the trial court will apply the Frye test only if the scientific principle, technique, or test offered by the expert to support his or her conclusion is new or novel. In re K.T., 297 Ill. Dec. 38, 836 N.E.2d 769 (App. Ct. 1st Dist. 2005).

Generally, a scientific technique is new or novel, for purposes of Frye test for admissibility of expert testimony, if it is original or striking or does not resemble something formerly known or used. In re K.T., 297 Ill. Dec. 38, 836 N.E.2d 769 (App. Ct. 1st Dist. 2005).

Under the Frye test, the proponent of scientific evidence bears the burden of demonstrating that the scientific theory relied upon by the expert has gained general acceptance in the scientific field. In re Detention of Hauge, 285 Ill. Dec. 751, 812 N.E.2d 571 (App. Ct. 3d Dist. 2004).

A court may determine the general acceptance of a scientific principle or methodology in either of two ways: (1) based on the results of a Frye hearing; or (2) by taking judicial notice of unequivocal and undisputed prior judicial decisions or technical writings on the subject. K. Broun, McCormick on Evidence § 203, at 828-39 (6th ed.2006). See also Jones v. United States, 548 A.2d 35 (D.C.App.1988). People v. McKown 226 Ill.2d 245, 254, 875 N.E.2d 1029, 1034, 314 Ill.Dec. 742, 747 (Ill.,2007) In the jurisdictions that follow Frye, the proponent of the evidence must prove general acceptance by surveying scientific publications, judicial decisions, or practical applications, or by presenting testimony from scientists as to the attitudes of their fellow scientists. K. Broun, McCormick on Evidence § 203, at 828-39 (6th ed.2006)

To conclude, the Frye admissibility test concerns itself almost exclusively with the methodology that is being employed, rather than the actual opinion which is drawn therefrom. Frye also requires courts to wait for the sciences to accept a methodology prior to admission.

The Daubert Standard

Daubert employs the Frye "general acceptance test" as only one factor in considering the admissibility of scientific evidence. Under Daubert, scientific evidence can be validated in court even before it has reached a state of acceptance in the relevant scientific community. On the other hand, under Daubert, an acceptable piece of scientific evidence can be rejected if it is misleading or impairs the factfinding process.

In Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579, 113 S. Ct. 2786, 125 L. Ed. 2d 469, 27 U.S.P.Q.2d (BNA) 1200, Prod. Liab. Rep. (CCH) P 13494, 37 Fed. R. Evid. Serv. 1, 23 Envtl. L. Rep. 20979 (1993), the United States Supreme Court determined that Federal Rule of Evidence 702 had superseded the Frye test, and enunciated a new standard for determining the admissibility of novel scientific evidence, establishing a "gatekeeping" role for federal district courts and enunciating several factors to be considered in determining the admissibility of new scientific evidence.

The Daubert court noted that the rigid "general acceptance" requirement for admission of scientific evidence under Frye would be at odds with "liberal thrust" of Federal Rules of Evidence and their general approach of relaxing traditional barriers to "opinion" testimony. The Daubert court therefore stated that the admissibility of scientific evidence should be subject to a variety of considerations.

First, the subject of the testimony must be "scientific knowledge rooted 'in the methods and procedures of science.' " Daubert then set out four nonexclusive factors which can be considered in determining admissibility: (1) whether the theory or technique can be, and has been, tested; (2) whether it has been subjected to peer review and publication; (3) the known or potential rates of error; and (4) whether it is generally accepted in the relevant scientific community. Next, the court must determine that the evidence is relevant to the facts in the case at hand. Finally, the court should consider the impact of other rules of evidence, for example, whether the evidence is more prejudicial than probative, which could still render the evidence inadmissible.

As noted by the Connecticut Supreme Court, when they were discussing the admissibility of the horizontal gaze nystagmus exercise:

"[T]he Frye test serves now as an "important factor" in the trial judge's assessment. Indeed, "if a trial court determines that a scientific methodology has gained general acceptance, then the Daubert inquiry will generally end and the conclusions derived from that methodology will generally be admissible."

"...[I]n the event a scientific principle has not gained general acceptance, a proponent may still establish its reliability or validity by other means. Among the many factors that a proponent may rely on are: whether the methodology has been tested and subjected to peer review, the known or potential rate of error, the extent to which the scientific technique relies on subjective interpretations and judgments by the testifying expert, whether the testifying expert can present the methodology in a manner that the fact finder can reasonably draw its own conclusions therefrom, and whether the proffered expert testimony was developed solely for in-court use. In addition, the prestige and background of the testifying expert witness can play a role in determining whether a novel technique employed by that individual is likely to have scientific merit.

State v. Carlson 45 Conn.Supp. 461, 463-464, 720 A.2d 886, 888 (Conn.Super.,1998) (Citations in body of quotation omitted)

Other Considerations when Evaluating the Admissibility of Scientific Evidence

In People v. Kelly, 17 Cal. 3d 24, 130 Cal. Rptr. 144, 549 P.2d 1240 (1976), the state of California adopted a modified version of the Frye test. The court created a three-part test for the admissibility of novel scientific evidence. First, the reliability of the method must be established, usually by experts who can demonstrate that the method is generally accepted within the relevant community. Next, the testifying expert must be properly qualified. Finally, the proponent must show that the correct scientific procedures were used in the case before the court. This test became known as the Kelly/Frye test. Alice B. Lustre, J.D, American Law Review "Post-Daubert Standards for Admissibility of Scientific and Other Expert Evidence in State Courts", 90 ALR 453 (5th Ed. 2001: online edition updated weekly)

In, State v. Brown, 297 Or. 404, 687 P.2d 751 (1984), (a pre-Daubert decision still of value) the Oregon Supreme Court held that a court must identify and evaluate the probative value of the proffered scientific evidence, consider how that evidence might impair rather than help the trier of fact, and decide whether truthfinding is better served by admission or exclusion. Brown, 297 Or. at 409, 687 P.2d 751. The Brown court identified a number of factors that could affect a trial court's decision on admissibility of proffered scientific evidence:

"(1) The technique's general acceptance in the field;

"(2) The expert's qualifications and stature;

"(3) The use which has been made of the technique;

"(4) The potential rate of error;

"(5) The existence of specialized literature;

"(6) The novelty of the invention; and

"(7) The extent to which the technique relies on the subjective interpretation of the expert." 297 Or. at 417, 687 P.2d 751.

In a footnote, Brown mentioned somewhat overlapping additional factors to consider:

"(1) The potential error rate in using the technique;

"(2) The existence and maintenance of standards governing its use;

"(3) Presence of safeguards in the characteristics of the technique;

"(4) Analogy to other scientific techniques whose results are admissible;

"(5) The extent to which the technique has been accepted by scientists in the field involved;

"(6) The nature and breadth of the inference adduced;

"(7) The clarity and simplicity with which the technique can be described and its results explained;

"(8) The extent to which the basic data are verifiable by the court and jury;

"(9) The availability of other experts to test and evaluate the technique;

"(10) The probative significance of the evidence in the circumstances of the case; and

"(11) The care with which the technique was employed in this case." 297 Or. at 418-419 n. 5, 687 P.2d 751.

Determining the Relevant Scientific Community

The defense attorney may also need to argue that a particular state expert does come from the correct 'relevant community', and hence the State cannot prove up the admissibility of the evidence with a qualified expert. For example, one court found that for purposes of determining the scientific validity of the Horizontal Gaze Nystagmus (HGN) test, the relevant scientific communities included the disciplines of pharmacology, ophthalmology, optometry, behavioral psychology, highway safety, neurology, and criminalistics. State v. O'Key, 321 Or. 285, 899 P.2d 663 (1995)

Counsel should therefore remain vigilant if the State produces a witness who does not come from the correct discipline. For example, a state chemist does not belong to any of the above discussed disciplines, and would not qualify to validate the HGN test without further foundation.

The Court as a Gatekeeper under Daubert

The Daubert Court held that trial judges have an important role to play as "gatekeepers," charged with the responsibility of ensuring that proffered expert scientific testimony must be "not only relevant, but reliable." Daubert, 509 U.S. at ----, 113 S.Ct. at 2795, 125 L.Ed.2d at 480. The Court first focused on the language of FRE 702, which clearly contemplates some degree of regulation in the admission of expert testimony concerning "scientific * * * knowledge." Unless the proffered evidence is supported by appropriate validation, it cannot qualify as "scientific knowledge," id., 509 U.S. at ----, 113 S.Ct. at 2795, 125 L.Ed.2d at 480-81, and "appropriate validation" refers to scientific validity, id., 509 U.S. at ----, 113 S.Ct. at 2796-98, 125 L.Ed.2d at 483-84. Thus, admissibility of scientific evidence requires a showing that it is based on scientifically valid principles. In performing its role as "gatekeeper," the trial court ensures that the trier of fact does not attach an undue aura of reliability to "scientific" evidence that is not scientifically valid. Evidence that purports to be based on science beyond the common knowledge of the average person that does not meet the judicial standard for scientific validity can mislead, confuse, and mystify the jury.

As stated in State v. O'Key 321 Or. 285, 899 P.2d 663 (Or.,1995):

"The [Daubert] Court denominated scientific validity as the linchpin of admissibility because validity relates to whether the methods in question are capable of measuring what they purport to measure. Daubert recognized that reliability and validity differ as scientific measures. 509 U.S. at ---- n. 9, 113 S.Ct. at 2795 n. 9, 125 L.Ed.2d at 481 n. 9. Whereas validity describes how well the scientific method reasons to its conclusions, reliability describes the ability of the scientific method to produce consistent results when replicated. David H. Kaye & David A. Freedman, Reference Guide on Statistics, in Reference Manual on Scientific Evidence 331, 341-42 (Federal Judicial Ctr, ed 1994). "For example, a new test for blood alcohol level may be invalid in that it grossly underestimates the amount of alcohol in one's bloodstream, and yet be reliable in that it underestimates the blood alcohol level in one's bloodstream by the same amount every time." Developments in the Law, Confronting the New Challenges of Scientific Evidence, 108 Harv.L.Rev. 1481, 1534 (1995). See also Brown, 297 Or. at 427, 687 P.2d 751 ("Accuracy can be broken down into two categories: reliability and validity. The reliability of a test is the consistency with which the test measures whatever it is that it measures. * * * The validity of the test is the extent to which the test measures that which it claims to measure."); David L. Faigman, To Have and Have Not: Assessing the Value of Social Science to the Law as Science and Policy, 38 Emory L.J. 1005, 1010 n. 16 (1989) (defining reliability and validity and providing an example illustrating the difference). With little discussion, the Supreme Court concluded that the ultimate concern for a trial judge must be evidentiary reliability, that is trustworthiness, but stated that such reliability must be based on scientific validity. Daubert, 509 U.S. at ---- n. 9, 113 S.Ct. at 2795 n. 9, 125 L.Ed.2d at 481 n. 9.

The role of the trial court as "gatekeeper" is to ensure that trier of fact does not attach undue aura of reliability to proffered expert scientific testimony that is not scientifically valid, in order to prevent jury from being misled, confused, or mystified by evidence which purports to be based on science beyond common knowledge of average person but which does not meet judicial standard for scientific validity. State v. O'Key, 321 Or. 285, 899 P.2d 663 (1995)

Opinion Testimony - the Expert's Qualifications Must Also Be Established

Generally, the opinion testimony of an expert is admissible if the expert is qualified by knowledge, skill, experience, training, or education in a field that has at least a modicum of reliability and the testimony would assist the jury in understanding the evidence. Kimble v. Earle M. Jorgenson Co., 294 Ill. Dec. 402, 830 N.E.2d 814 (App. Ct. 1st Dist. 2005).

Expert testimony is admissible if the proffered expert's experience and qualifications afford him knowledge not common to laypersons. People v. Williams, 266 Ill. Dec. 168, 773 N.E.2d 1238 (App. Ct. 3d Dist. 2002).

Despite the novelty of the conclusion reached by an expert, for purposes of admitting scientific evidence under the Frye general acceptance test, the fact finder may consider the opinion if the underlying methodology used to generate the opinion is reasonably relied on by experts in the field. Kane v. Motorola, Inc., 268 Ill. Dec. 688, 779 N.E.2d 302 (App. Ct. 1st Dist. 2002), as modified on denial of rehearing, (Nov. 27, 2002).

The Defense Attorneys Role in Contesting Scientific Evidence

"To deal effectively with scientific evidence, attorneys must know more than the rules of evidence. They must know something of the scientific principles as well. While they can rely on suitably chosen experts for advice about the more arcane points, they must have a sufficient grasp of the field to see what is essential and what is unnecessary detail and verbiage if they are to develop or counteract the evidence most effectively." K. Broun, McCormick on Evidence § 203, at 828-39 (6th ed.2006)

If you are reading this book, you are already generally prepared for the task at hand. In the great majority of DUI cases, you are likely to encounter several pieces of evidence where this chapter's focus is applicable: first we have the police officer's testimony on field sobriety tests; next we have the results of alcohol-concentration tests, and lastly is any witnesses opinion testimony.

Field Sobriety Tests Generally

Courts are split as to whether field sobriety tests such as the walk and turn or one-legged stand are evidence that are subject to the specialized standards discussed above.

For example, in State v. Homan, 89 Ohio St.3d 421, 732 N.E.2d 952
(Ohio 2000) the Ohio Supreme Court held that, for the results of a field sobriety test to serve as evidence of probable cause to arrest driver for driving under the influence (DUI), the police must have administered the test in strict compliance with standardized testing procedures.:

"When field sobriety testing is conducted in a manner that departs from established methods and procedures, the results are inherently unreliable. In an extensive study, the National Highway Traffic Safety Administration ("NHTSA") evaluated field sobriety tests in terms of their utility in determining whether a subject's blood-alcohol concentration is below or above the legal limit. The NHTSA concluded that field sobriety tests are an effective means of detecting legal intoxication "only when: the tests are administered in the prescribed, standardized manner[,] * * * the standardized clues are used to assess the suspect's performance[, and] * * * the standardized criteria are employed to interpret that performance." National Highway Traffic Safety Adm., U.S. Dept. of Transp., HS 178 R2/00, DWI Detection and Standardized Field Sobriety Testing, Student Manual (2000), at VIII-3. According to the NHTSA, "[i]f any one of the standardized field sobriety test elements is changed, the validity is compromised." Id. Experts in the areas of drunk driving apprehension, prosecution, and defense all appear to agree that the reliability of field sobriety test results does indeed turn upon the degree to which police comply with standardized testing procedures. See, e.g., 1 Erwin, Defense of Drunk Driving Cases (3 Ed.1997), Section 10.06 [4]; Cohen & Green, Apprehending and Prosecuting the Drunk Driver: A Manual for Police and Prosecution (1997), Section 4.01.

Although the Homan decision did not specifically refer to Daubert or Frye, the use of terms such as 'testing guidelines' and 'reliability' clearly rang the same bell. Homan was later described as an application of the Ohio Evidence Rule 702 governing expert testimony. See State v. Nutter 128 Ohio Misc.2d 24, 27, 811 N.E.2d 185, 188 (Ohio Mun.,2004)(describing Homan as "an application of an existing Rule of Evidence relating to the admissibility of evidence by expert witnesses.") The Homan decision was later superseded by a state statute allowing field sobriety tests to be admitted without strict compliance with NHTSA rules.

Other states have held that field sobriety tests (other than HGN discussed separately below) are not 'scientific tests' subject to specialized rules of admissibility. In People v. Vega, 145 Ill.App.3d 996, 1001, 99 Ill.Dec. 808, 496 N.E.2d 501 (1986), the Illinois appellate court observed that the "walk the line," "one leg stand," and "finger to nose" field sobriety tests "are not so abstruse as to require a foundation other than the experience of the officer administering them." See also People v. Sides, 199 Ill.App.3d 203, 145 Ill.Dec. 160, 556 N.E.2d 778 (1990).

Similarly, in People v. Bostelman 325 Ill.App.3d 22, 33, 756 N.E.2d 953, 962, 258 Ill.Dec. 679, 688 (Ill.App. 2 Dist.,2001) it was stated that:

"The trial court was fully capable of drawing on its own experiences in determining the state of defendant's sobriety from his performance of the simple physical tasks utilized in the field sobriety tests other than the HGN. The trial court was within its rights in determining, aside from any evidence that [the officer] arranged the tests in accordance with his training or previous experience, that the field sobriety tests measured abilities that are tested innumerable times throughout the average day of the normally active person. Indeed, so fundamental are such exercises of balance, coordination, and basic cognition to the activity of the average person that "even a layperson is competent to testify regarding a person's intoxication from alcohol, because such observations are within the competence of all adults of normal experience."

Other courts have also rejected attempts to attack field sobriety tests under Frye on the ground that field sobriety testing is not and does not purport to be scientific evidence, but is merely the observation of generally recognized indicia of intoxication. See, e.g., Bremond v. State 1994 WL 16196672, 3 (Alaska App.) (Alaska App.,1994) Scott v. State, 624 So.2d 230, 232 (Ala.Crim.App.1993); Crampton v. State, 525 A.2d 1087, 1094 (Md.Spec.App.1987), aff'd, 550 A.2d 693 (Md.1988); State v. Gilbert, 751 S.W.2d 454, 459 (Tenn.Crim.App.1988); see also State ex rel. Hamilton v. City Court of Mesa, 799 P.2d 855, 859 & n. 3 (Ariz.1990); City of West Bend v. Wilkens, 693 N.W.2d 324, 278 Wis.2d 643, 2005 WI App 36 (Wis.App. Jan 12, 2005). In Commonwealth v. Ragan, 438 Pa.Super. 505, 652 A.2d 925 appeal denied, 541 Pa. 650, 664 A.2d 540 (1995), the Pennsylvania appellate court held that the one-legged stand, finger-to-nose and walking-in-a-straight-line tests for sobriety are admissible as nonscientific evidence because they involve observations within the common experience of the ordinary citizen. Accord Seewar v. Town of Summerdale, 601 So.2d 198 (Ala.Crim.App.1992), cert. denied, (Ala.1992); Nuyt v. Director of Revenue, 814 S.W.2d 690 (Mo.App.E.D.1991).

In State v. Ferrer, 95 Hawai'i 409, 23 P.3d 744 (App.2001), the court stated:

"It is generally recognized, however, that the foundational requirements for admission of psychomotor FST evidence differ from the foundational requirements for admission of HGN evidence. Psychomotor FSTs test balance and divided attention, or the ability to perform multiple tasks simultaneously. While balancing is not necessarily a factor in driving, the lack of balance is an indicator that there may be other problems. Poor divided attention skills relate directly to a driver's exercise of judgment and ability to respond to the numerous stimuli presented during driving. The tests involving coordination (including the walk-and-turn and the one-leg-stand) are probative of the ability to drive, as they examine control over the subject's own movements. Because evidence procured by administration of psychomotor FSTs is within the common experience of the ordinary citizen, the majority of courts that have addressed the issue generally consider psychomotor FSTs to be nonscientific evidence."

Florida courts have reached a well-conceived compromise. While allowing a defendant's actual performance on the walk-and-turn test, one-legged stand, balance test and finger-to-nose test, to be admitted as 'nonscientific', the same courts have forbidden a police officer from using specialized terms to assess the performance in court as giving a misleading aura of science:

"While the psychomotor tests are admissible, we agree with defendants that any attempt to attach significance to defendants' performance on these exercises beyond that attributable to any of the other observations of a defendant's conduct at the time of the arrest could be misleading to the jury and thus tip the scales so that the danger of unfair prejudice would outweigh its probative value. The likelihood of unfair prejudice does not outweigh the probative value as long as the witnesses simply describe their observations. [citation omitted]

"Reference to the exercises by using terms such as "test," "pass," "fail," or "points," however, creates a potential for enhancing the significance of the observations in relationship to the ultimate determination of impairment, as such terms give these layperson observations an aura of scientific validity. [citations omitted] Therefore, such terms should be avoided to minimize the danger that the jury will attach greater significance to the results of the field sobriety exercises than to other lay observations of impairment."

State v. Meador, 674 So.2d 826, 833, 21 Fla. L. Weekly D1152 (Fla. 1996)

Similarly, in U.S. v. Horn, 185 F.Supp.2d 530, 559, 58 Fed. R. Evid. Serv. 357, 357 (D.Md. Jan 31, 2002) the court ruled that:

"A police officer trained and qualified to perform SFSTs may testify with respect to his or her observations of a subject's performance of these tests, if properly administered, to include the observation of nystagmus, and these observations are admissible as circumstantial evidence that the defendant was driving while intoxicated or under the influence. In so doing, however, the officer may not use value-added descriptive language to characterize the subject's performance of the SFSTs, such as saying that the subject "failed the test" or "exhibited" a certain number of "standardized clues" during the test."

Horizontal Gaze Nystagmus (HGN)

In People v. McKown 226 Ill.2d 245, 875 N.E.2d 1029, 314 Ill.Dec. 742 (Ill.,2007) the Illinois Supreme Court held that: (1) horizontal gaze nystagmus (HGN) evidence was novel, for the purpose of Frye testing; (2) the trial and appellate courts erred when they took judicial notice of the general acceptance of the reliability of the HGN test as an indicator of alcohol impairment based on prior judicial decisions; (3) the trial and appellate courts could not take judicial notice of the HGN test as a reliable indicator of alcohol impairment based on technical writings on the subject; and (4) the trial court error in admitting HGN test results as evidence of alcohol impairment was not harmless.

Therefore, the McKown Court ordered the parties to conduct a Frye hearing regarding the admissibility of HGN in Illinois. The McKown court specifically declined to adopt a Daubert standard in the absence of a request by any of the parties to so adopt. As of the date of this publication, a decision on the issue had not been made. People v. McKown, 226 Ill.2d 245, 247, 875 N.E.2d 1029, 1031, 314 Ill.Dec. 742, 744 (Ill. 2007) ("FN2. The parties have not argued, and we have not considered, the adoption of the evidentiary standard set forth in Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579, 113 S.Ct. 2786, 125 L.Ed.2d 469 (1993). We will not raise the issue sua sponte.")

The admissibility of the HGN test has been an issue of for courts since the test was adopted by the NHTSA in 1984. Regarding admissibility, courts have disagreed about whether the test is "scientific." Several courts consider the HGN test no more scientific than other field sobriety tests. See, e.g., State v. Sullivan, 310 S.C. 311, 426 S.E.2d 766 (1993); State v. Murphy, 451 N.W.2d 154 (Iowa 1990); State v. Bresson, 51 Ohio St.3d 123, 554 N.E.2d 1330 (1990). The rationale for this approach is that the HGN test is not based on scientific expertise, but only on the personal observations of the officer who administered the test. Texas courts have held HGN evidence may be admitted to prove intoxication and any witness, lay or expert, may give an opinion on the issue of intoxication. Finley v. State, 809 S.W.2d 909, 913-14 (Tex.App.1991). HGN evidence, however, may not be used to prove an exact BAC. Richardson v. State, 766 S.W.2d 538, 540 (Tex.App.1989).

The Supreme Court of Montana, in State v. Clark, 234 Mont. 222, 762 P.2d 853 (1988), concluded that Montana's liberal foundation requirements for expert testimony permitted the admission of HGN test evidence. The court noted that Montana does not follow the Frye test, reasoning:

"Unless an exaggerated popular opinion of the accuracy of the particular technique makes its use prejudicial or likely to mislead the jury, the better approach is to admit all relevant scientific evidence in the same manner as other expert testimony and allow its weight to be attacked by cross-examination or refutation. [Citation omitted.]" 234 Mont. at 227, 762 P.2d 853.

Other courts have rejected that analysis, holding that the HGN test is a scientific technique, requiring compliance with the appropriate foundational showing for the admission of scientific evidence. See, e.g., Leahy, 8 Cal.4th at 587, 34 Cal.Rptr.2d at 663, 882 P.2d at 321; Yell v. State, 856 P.2d 996 (Okla.Crim.App.1993); State v. Garrett, 119 Idaho 878, 811 P.2d 488 (1991); State v. Superior Court, 149 Ariz. 269, 718 P.2d 171 (1986); State v. Witte, 251 Kan. 313, 836 P.2d 1110 (1992); State v. Cissne, 72 Wash.App. 677, 865 P.2d 564 (1994). The rationale for this latter approach is that the HGN test is distinguished from other field sobriety tests because science, rather than common knowledge, provides the legitimacy for HGN testing.

Most courts that have applied a Daubert-type analysis to HGN testing as a field sobriety test have found it admissible. (See e.g. Emerson v. State, supra, 880 S.W.2d at pp. 764-770; State v. Conner (1995) 132 Or.App. 478, 888 P.2d 1087, 1089; State v. Gleason (1992) 123 Idaho 62, 844 P.2d 691, 694-695; State v. Murphy (IA 1990) 451 N.W.2d 154, 165-158; State v. Clark (1988) 234 Mont. 222, 762 P.2d 853, 856-857; see also State v. Bresson (1990) 51 Ohio St.3d 123, 554 N.E.2d 1330, 1332-1336.) Some courts have found the record before them insufficient as a basis for determining general scientific acceptance. (See e.g., Com. v. Apollo (1992) 412 Pa.Super. 453, 603 A.2d 1023, 1025-1028.)

The Connecticut Supreme Court ruled HGN admissible in State v. Carlson, 45 Conn. Supp. 461, 720 A.2d 886 (Super. Ct. 1998) (general acceptance of horizontal gaze nystagmus (HGN) testing for DUI is sufficient to satisfy Daubert, remaining objections go to weight).

In State v. Gleason, 123 Idaho 62, 844 P.2d 691 (1992), the Idaho Supreme Court found the horizontal gaze nystagmus test admissible under Idaho Rule of Evidence 702, which is identical to Federal Evidence Rule 702.

The state of Oregon has adopted the Daubert test for determining the admissibility of scientific and other expert evidence. The Oregon Supreme Court in State v. O'Key, 321 Or. 285, 899 P.2d 663 (1995) held that: subject to a foundational showing that the officer who administered test was properly qualified, that the test was administered properly, and that the test results were recorded accurately, the HGN test evidence was admissible to establish that a defendant was under influence of intoxicating liquor, but that the HGN test evidence was not admissible to prove that defendant had blood alcohol content (BAC) of .08 percent or more.


In some states, PBT devices are admissible for proving probable cause to arrest, but are statutorily inadmissible at trial. Additionally, challenges to the admissibility of these devices based upon their general unreliability or unproven methodology under Frye and Daubert have also been reported.

These challenges depend upon defense counsel having a solid understanding of the methodologies and shortcomings of the preliminary breath-tester devices. Such specific information is found elsewhere in this book.

In State v. Smith130 Wn.2d 215, 222, 922 P.2d 811 (1996), the defendant desired to admit the PBT result into evidence in his defense. The Washington Supreme Court held that results garnered from PBTs were 'inadmissible for any purpose' absent 'a Frye hearing on the PBT, or specific approval of the device and its administration by the state toxicologist.'

In Halley v. State, Not Reported in P.2d, 1991 WL 11650674, Alaska App., January 16, 1991 (NO. A-3463) the Alaska Court of Appeals found that a PBT result did not satisfy Frye. ("While the Department of Public Safety has promulgated regulations governing testing methods, equipment, operator certification, and instrument calibration with regard to Intoximeter testing, no such regulations cover preliminary breath tests.")

In State v. Damon, 2005 MT 218, 328 Mont. 276, 119 P.3d 1194, the Montana Supreme Court found that the Alco-Sensor III PBT was admissible without a Daubert hearing ("a PBT or PAST using fuel cell technology does not represent a novel scientific technique that requires a court to apply the Daubert factors"). In an interesting later comment, it was said:

"It bears mentioning that the underlying "science" involved in PBT instruments is not the problem. Rather, it is the lack of training, the failure to set rigorous calibration and testing standards and the actual field use of these instruments that contributes to their being unreliable for substantive evidence purposes."

State v. Clifford 328 Mont. 300, 320, 121 P.3d 489, 503 (Mont.,2005)

In United States v. Iron Cloud, 171 F.3d 587 (8th Cir.1999) a portable breath test ("PBT") was taken at the scene, and the results were part of the evidence at trial. Id. Defendant moved for a Daubert hearing regarding the expert testimony which would be presented about the PBT testing to determine whether it was reliable and relevant, but the district court judge refused to allow such a hearing and he summarily found that PBT testing was " 'recognized by the scientific community.' " Id. at 590, 113 S.Ct. 2786 (quoting from the trial transcript). The Eighth Circuit reversed, finding a Daubert hearing should have been held as the PBT is not recognized as reliable other than for purposes of establishing probable cause or as a preliminary screening test. Id. at 590-91 (concluding that admitting the PBT test results was not harmless error).

As stated in Iron Cloud:

"[A]lmost every state that has addressed the issue has refused to admit the results of the test for purposes other than probable cause. " FN5 Although the admissibility of evidence is governed by federal standards, in the face of this overwhelming case law as to the limited reliability of the PBT, we conclude, without further foundation being laid, that the PBT is not reliable as anything more than a screening test to be used for probable cause.

FN5. See also Boyd v. City of Montgomery, 472 So.2d 694, 697 (Ala.Crim.App.1985) (holding that preliminary breath tests are only admissible to establish probable cause); Patrick v. State, 295 Ark. 473, 750 S.W.2d 391, 394 (1988) (stating that PBT's are admissible only on behalf of the defendant because they are unreliable); Attix v. Voshell, 579 A.2d 1125, 1129 (Del.Super.Ct.1989) (holding that the PBT can be admitted only for probable cause and not for substantial evidence because no court has established that it is reliable); State v. Zell, 491 N.W.2d 196, 197 (Iowa Ct.App.1992) (stating, "[t]he results of the preliminary screening test are inadmissible because the test is inherently unreliable and may register an inaccurate percentage of alcohol present in the breath, and may also be inaccurate as to the presence or absence of any alcohol at all"); People v. Keskinen, 177 Mich.App. 312, 441 N.W.2d 79, 82 (1989) (holding that court erred in admitting evidence of the defendant's preliminary breath test); Justice v. Director of Revenue, 890 S.W.2d 728, 731 (Mo.Ct.App.1995) (stating that PBTs are not admissible by statute); State v. Strizich, 286 Mont. 1, 952 P.2d 1365, 1371 (1997) (holding that the PBT is intended only for determining probable cause); State v. Klingelhoefer, 222 Neb. 219, 382 N.W.2d 366, 369-70 (1986) (holding that preliminary test is only relevant for limited purpose of establishing probable cause); City of Fargo v. Ruether, 490 N.W.2d 481, 482-83 (N.D.1992) (holding that an alcohol screening test cannot be admitted if a defendant admits probable cause); Commonwealth v. Stanley, 427 Pa.Super. 422, 629 A.2d 940, 942 (1993) (stating that PBT results are inadmissible); Jones v. Town of Marion, 28 Va.App. 791, 508 S.E.2d 921 (1999) (citing to state statute which provides that preliminary breath tests are only to be used in determining probable cause); Thompson v. State Dept. of Licensing, 91 Wash.App. 887, 960 P.2d 475, 477 (1998) (holding that "the results of a portable breath test are not admissible as evidence at trial or to establish probable cause for arrest"); State v. Beaver, 181 Wis.2d 959, 512 N.W.2d 254, 258-59 (1994) (PBT not admitted). Compare State v. Huettl, 379 N.W.2d 298, 305 (S.D.1985) (holding that PBT results were inadmissible because of state implied consent statutes); State v. Anderson, 359 N.W.2d 887 (S.D.1984) (holding that because the PBT is a field sobriety test for establishing probable cause, the results are not admissible against a defendant.).

However, in People v. Bury (1996) 41 Cal.App.4th 1194, 1201-1202 the defendants request for a Kelly-Frye reliability hearing was denied, the court finding that a preliminary alcohol screening (PAS) device "is not a novel technique" nor is "the ' fuel cell' device" in the particular machine "a new scientific development".


In State v. Hofer, 512 N.W.2d 482 (S.D. 1994), the South Dakota Supreme Court held that Daubert had overturned Frye and would be the test applied for determining the admissibility of scientific evidence. Hofer involved the use of intoxilyzer results, but the challenge was to the partition ratios employed by the Intoxilyzer in order to determine blood alcohol concentration. Noting that such evidence was presented concerning those inaccuracies in the ratios and that the jury weighed that evidence, the court found that Daubert was satisfied. In other words, Hofer found that the scientific validity of breathalyzers, unlike other evidence, was best left for the jury to decide.

Blood - Enzymatic Analysis

Indeed, as the Kansas Supreme Court noted, "[e]nzyme analysis is not a novel method for determining blood alcohol concentration; the first journal published on the method appeared in 1951. See R. Bonnichsen & H. Theorell, An Enzymatic Method for the Microdetermination of Ethanol, 3 Scand. J. Clinical Lab. Invest. 58 (1951)." State v. Graham, supra, 61 P.3d at 668.

In State v. Kirsch 263 Conn. 390, 820 A.2d 236 (Conn. 2003) the Connecticut court upheld the use of enzymatic blood alcohol testing methods, stating:

"Therefore, we conclude that the methodology underlying the hospital blood test at issue is not the type of novel, experimental or innovative scientific technique which triggers the need for a Porter hearing. Accordingly, the trial court properly determined that the reliability of the test was so well established that a Porter hearing was not a necessary predicate to its admission into evidence."

Additionally, other jurisdictions have recognized the validity of blood alcohol enzymatic analysis for legal purposes. See, e.g., Mehl v. State, 632 So.2d 593, 595 (Fla.1993); Barna v. Commissioner of Public Safety, 508 N.W.2d 220, 222 (Minn.App.1993); see also State v. Graham, 275 Kan. 176, 61 P.3d 662, 668 (2003) ("enzyme analysis technique's validity is generally accepted as reliable within the scientific field of determining blood alcohol concentration"; test meets admissibility requirements "as a matter of law").

Urine Alcohol Testing

An unsuccessful attempt to challenge the general scientific reliability of urine-alcohol testing and conversion to whole-blood equivalence was raised in People v. Municipal Court (Sansone) (1986) 184 Cal.App.3d 199, 201. In reversing a trial court ruling which barred urine-alcohol testing until a Kelly-Frye hearing regarding reliability of the process was held, the appellate court stated:

"There is nothing new about using the urine test to determine blood-alcohol content. It has been routinely used in California courts for over 20 years (see People v. Conterno (1959) 170 Cal.App.2d Supp. 817, 823, 339 P.2d 968). The Legislature, some 20 years ago, incorporated urine tests into the implied consent law (Veh.Code, § 23157, see former Veh.Code, § 13353, added Stats.1966, ch. 138. § 1). Urine, blood and breath tests are all carefully regulated to assure the accuracy of the test results (see Cal.Admin.Code, tit. 17, part 1, § 1215 et seq.). Real party argues that urine testing has been commonplace for many years but argues that this deals only with individual samples and not with the acceptability of the procedure itself. There is no appellate decision that establishes the general acceptance of urinalysis testing, says real party, and since the People failed to present any evidence on that point, the results must be excluded. However, were the procedure itself not acceptable, its use would not be commonplace; were the procedure not acceptable, the Legislature would not have included it as an alternative of testing for blood alcohol levels.

"Real party suggests the procedure for collecting urine samples makes the results unreliable because one can never completely void one's bladder. However, the conversion factor derived after empirical studies takes this into account. The accuracy of a particular test may be compromised by the subject failing to completely void his bladder but this does not detract from the validity of the procedure itself.

"Real party points out that just because a procedure has been used for years should not place it beyond attack. But absent a showing of new information as to a particular scientific principle or discovery there is no reason to challenge an already established procedure."

Retrograde Extrapolation of Alcohol - Reliability

Few courts have touched upon the reliability of retrograde extrapolation.

In Mata v. State 46 S.W.3d 902, 913 -914 (Tex.Crim.App.,2001) the court held the theory reliable, providing enough factors were known by the expert who was attempting to employ it. Specifically:

"Our study of retrograde extrapolation leads us to several conclusions. Initially, we recognize that even those who believe retrograde extrapolation is a reliable technique have utilized it only if certain factors are known, such as the length of the drinking spree, the time of the last drink, and the person's weight. FN88 McDougall knew none of those factors, or any other individual characteristics of Mata, for that matter. In addition, there appears to be general disagreement on some of the fundamental aspects of the theory, such as the accuracy of Widmark's formulas, whether a standard elimination rate can be reliably applied to a given subject, and the effect that food in the stomach has on alcohol absorption. Nevertheless, given the studies, other concepts seem indisputable, including that multiple tests will increase the ability to plot a subject's BAC curve, a test nearer in time to the time of the alleged offense increases the ability to determine the subject's offense-time BAC, and the more personal information known about the subject increases the reliability of an extrapolation.

"We believe that the science of retrograde extrapolation can be reliable in a given case. The expert's ability to apply the science and explain it with clarity to the court is a paramount consideration. In addition, the expert must demonstrate some understanding of the difficulties associated with a retrograde extrapolation. He must demonstrate an awareness of the subtleties of the science and the risks inherent in any extrapolation. Finally, he must be able to clearly and consistently apply the science.

"The court evaluating the reliability of a retrograde extrapolation should also consider (a) the length of time between the offense and the test(s) administered; (b) the number of tests given and the length of time between each test; and (c) whether, and if so, to what extent, any individual characteristics of the defendant were known to the expert in providing his extrapolation. These characteristics and behaviors might include, but are not limited to, the person's weight and gender, the person's typical drinking pattern and tolerance for alcohol, how much the person had to drink on the day or night in question, what the person drank, the duration of the drinking spree, the time of the last drink, and how much and what the person had to eat either before, during, or after the drinking.

"Obviously, not every single personal fact about the defendant must be known to the expert in order to produce an extrapolation with the appropriate level of reliability. As the Kentucky Supreme Court has recognized, if this were the case, no valid extrapolation could ever occur without the defendant's cooperation, since a number of facts known only to the defendant are essential to the process. If the State had more than one test, each test a reasonable length of time apart, and the first test were conducted within a reasonable time from the time of the offense, then an expert could potentially create a reliable estimate of the defendant's BAC with limited knowledge of personal characteristics and behaviors. In contrast, a single test conducted some time after the offense could result in a reliable extrapolation only if the expert had knowledge of many personal characteristics and behaviors of the defendant. Somewhere in the middle might fall a case in which there was a single test a reasonable length of time from the driving, and two or three personal characteristics of the defendant were known to the expert. We cannot and should not determine today the exact blueprint for reliability in every case. Suffice it to say that the factors must be balanced."

Mata v. State 46 S.W.3d 902, 915 -917 (Tex.Crim.App.,2001)(footnotes omitted)

Other courts have also rejected Frye or Daubert attacks on the general theory of retrograde extrapolation. See Commonwealth v. Senior, 744 N.E.2d 614 (Mass. 2001) stating that "retrograde extrapolation is a reliable method of determining blood alcohol levels"); and State v. Vliet, 19 P.3d 42, 60 (Haw. 2001) (taking "judicial notice that Widmark's formula is widely viewed as reliable"). An Arizona appellate court has stated that the science of retrograde extrapolation "has achieved general acceptance in the scientific field." Ring v. Taylor, 141 Ariz. 56, 69 n. 6, 685 P.2d 121, 134 n. 6 (Ariz.Ct.App.1984). In Smith v. Tuscaloosa, 601 So.2d 1136, 1140 (Ala.Crim.App.1992) the Alabama Court of Criminal Appeals stated that:

"[c]areful analysis of these studies indicates that retrograde extrapolation is an unreliable method of determining a defendant's condition at the time of operation. The inadequacies of retrograde extrapolation extend beyond mere technical inaccuracies to problems which are inherent in the basic premises and calculations of this technique. These inadequacies render retrograde extrapolation inherently untrustworthy and therefore inappropriate for use as evidence to convict drunk drivers." Ibid., quoting E. Abbott, "One for the Road"-The Reliability of Retrograde Extrapolation and the Implications for Vermont Statutes, 16 vt.L.Rev. 395, 397 (1991).

State Statutes Supplanting Frye or Daubert Admissibility Requirements

In DUI cases (unlike any other area of law where scientific evidence is sought to be introduced), many legislatures have passed laws that mandate the admissibility of intoxication evidence.

Still other laws further prohibit a defendant from having a full-blown hearing regarding the scientific validity of intoxication test evidence.

For example, after the Ohio Supreme Court issued its opinion in State v. Homan, 89 Ohio St.3d 421, 732 N.E.2d 952 (Ohio 2000) which prohibited field sobriety tests from being admitted unless they strictly complied with NHTSA standards, due to unreliability, the Ohio legislature passed a law mandating admissibility even where compliance with NHTSA had not occurred, which reads as follows:

"In any criminal prosecution or juvenile court proceeding for a violation of division (A) or (B) of this section, of a municipal ordinance relating to operating a vehicle while under the influence of alcohol, a drug of abuse, or alcohol and a drug of abuse, or of a municipal ordinance relating to operating a vehicle with a prohibited concentration of alcohol in the blood, breath, or urine, if a law enforcement officer has administered a field sobriety test to the operator of the vehicle involved in the violation and if it is shown by clear and convincing evidence that the officer administered the test in substantial compliance with the testing standards for any reliable, credible, and generally accepted field sobriety tests that were in effect at the time the tests were administered, including, but not limited too, any testing standards then in effect that were set by the National Highway Traffic Safety Administration, all of the following apply:

"(i) The officer may testify concerning the results of the field sobriety test so administered.

"(ii) The prosecution may introduce the results of the field sobriety test so administered as evidence in any proceedings in the criminal prosecution or juvenile court proceeding.

"(iii) If testimony is presented or evidence is introduced under (D)(4)(b)(i) or (ii) of this section, and if the testimony or evidence is admissible under the Rules of Evidence, the court shall admit the testimony or evidence and the trier of fact shall give it whatever weight the trier of fact considers to be appropriate."

R.C. 4511.19(D)(4)(b)

The validity of this law was upheld in State v. Nutter 128 Ohio Misc.2d 24, 25-26, 811 N.E.2d 185, 186 - 187 (Ohio Mun. 2004)

Other state statutes have rendered blood, breath and urine tests presumptively reliable and admissible based merely upon compliance with certain state standards. There, no Frye or Daubert hearing is (initially) necessary, and the burden then shifts to the opponent of the evidence to prove the methods are unreliable. "When the prosecution presents testimony in evidence concerning motor vehicle driver intoxication which includes an approved alcohol test method by a properly licensed operator, the fact finder may presume that the test procedure is reliable, the operator is qualified, and the presumptive meaning of the test as set forth in section 322.262(2) is applicable. The test results are admissible into evidence only upon compliance with the statutory provisions and the administrative rules enacted by its authority. Gillman v. State, 373 So.2d 935 (Fla. 2d DCA 1979); State v. Wills, 359 So.2d 566 (Fla. 2d DCA, 1978). The presumptions are rebuttable, and a defendant may in any proceeding attack the reliability of the testing procedures, the qualifications of the operator, and the standards establishing the zones of intoxicant levels. In addition, other competent evidence may be presented to rebut the presumptions concerning whether the person was under the influence of alcoholic beverages to the extent that his or her normal faculties were impaired." State v. Bender 382 So.2d 697, 699 (Fla., 1980)

In Bender, a challenge to such a process of determining reliability (and hence admissibility) outside of the court's purview was rejected:

"We believe the statutory authority empowering these agencies to approve testing methods for the implementation of breath- and blood-testing apparatus is proper and allowable.... The legislature merely assigned to the agencies the responsibility to establish proper uniform testing procedures for the protection of the public who must submit to the test or lose their driving privilege. There is a clear distinction between delegating to an executive agency law-making functions and assigning an executive agency supervisory responsibility over a police power function that already exists. To require legislative supervision of the administration of these scientific testing methods would require constant legislative hearings to develop the necessary expertise, which is neither practically possible nor required by our constitution. (citation omitted) We find the legislature properly exercised its authority in assigning to these agencies the responsibility of establishing uniform and reliable testing methods in this scientific area, particularly under the circumstances where the tests are part of a statutory scheme which prescribes the implied consent of all drivers to take these tests and where the tests and procedures are always subject to judicial scrutiny." State v. Bender 382 So.2d 697, 700 (Fla., 1980).

In certain states, if the test does not comply with the specifically established state rules and regulations, the test results are inadmissible even if the test itself was otherwise valid accurate and reliable. See, e.g People v Emrich (1986) 113 Ill 2d 343, 101 Ill Dec 632, 498 NE2d 1140 (no anticoagulant or preservative) People v. Murphy (1985), 108 Ill.2d 228, 91 Ill.Dec. 653, 483 N.E.2d 1288 (unlicensed laboratory).

In a minority of states, the results of a blood alcohol test are admissible into evidence without compliance with the administrative rules if the traditional predicate is laid which establishes the reliability of the test, the qualifications of the operator, and the meaning of the test results by expert testimony. See, e.g. Robertson v. State 604 So.2d 783, 790 (Fla.,1992) Where such a situation occurs, none of the statutory presumptions of intoxication can apply in the absence of compliance with the administrative rules . Id. Similarly, in People v Adams (1976, 1st Dist) 59 Cal App 3d 559, 131 Cal Rptr 190, the court held that noncompliance with certain procedures for maintenance of the breath-testing instruments went only to the weight of the blood alcohol concentration evidence.

Essentially, most states have statutes that grant their departments of public health or departments of state police, to establish methods of testing in DUI and DWI cases which replace the traditional predicates for the admission of scientific tests. Where such standards do exist, the burden then shifts to the opponent of the evidence to establish the invalidity of the scientific testing or methods involved.


In the DUI field, there are several predicate methods of attack on so-called scientific evidence. First, it must be established whether the evidence is 'scientific' or not, such as an HGN test or other field sobriety test.

If the evidence is deemed scientific, then the testing method must be proven to be scientifically reliable. Some courts follow the Frye method of establishing the admissibility of scientific evidence, while others follow Daubert or more localized definitions.

Lastly, certain types of DUI tests, such as blood or breath, must comply with specific state standards or statutory regulations instead of Frye or Daubert. In those situations, noncompliance with regulations can render the result entirely inadmissible.

Thus, knowledge of both the laws governing admissibility, as well as the theories underlying the scientific methods employed for testing, are a necessity for the expert DUI practitioner.

The DUI attorneys and DWI lawyers listed on this site include nationally published authors on DUI laws and DWI laws. These Drunk Driving Defense Attorneys have appeared in over 75 local television stations and 229 newspapers nationwide.

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Understanding DUI Scientific Evidence
This product provides an insider's perspective on the evolving technologies and procedures associated with the evidence associated with driving under the influence (DUI) charges. Leading defense attorneys guide the reader through the key stages and steps involved in successfully defending a client accused of driving while under the influence.

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