The Right to Challenge the Accuracy of Breath Test Results Under Alaska Law

JurisdictionAlaska,United States
Publication year2013
CitationVol. 30


Alaska Law Review
Volume 30, No. 1, June 2013
Cited: 30 Alaska L. Rev. 1


Paul A. Clark [*]


Section 28.90.020 of the Alaska Statutes provides that in prosecutions for drunk driving, "if an offense described under this title requires that a chemical test of a person's breath produce a particular result, and the chemical test is administered by a properly calibrated instrument approved by the Department of Public Safety, the result described by statute is not affected by the instrument's working tolerance." This provision appears to prohibit the defense from calling into question the accuracy of a breath test by introducing evidence of uncertainty inherent in the testing procedure. The statute is problematic because due process requires that defendants be permitted to challenge the evidence presented against them. Moreover, there is a strong argument that basing conviction on a single breath sample that is within a known margin of error is a per se violation of due process, as it bases guilt or innocence on a purely fortuitous result. This Article examines the issues with Alaska's statute and proposes using multiple breath tests as a simple, cost-effective solution to this potential abuse of due process.


Consider the following hypothetical trial testimony by a properly qualified expert witness in a drunk-driving case. The uncontested evidence which has been presented from video surveillance in the bar where the defendant was drinking and the testimony of the bar tender and twenty witnesses prove that she drank exactly four bottles of Alaskan Amber beer. Based on the defendant's size and the quantity of alcohol, her blood alcohol level could not possibly have been higher than .070 percent. Even though her breath test sample result was an apparent .080, due to the inherent uncertainty in such testing, the apparent result is within the margin of error for the instrument used, and does not contradict a legal blood or breath alcohol level.

Unfortunately for our hypothetical defendant, this defense may not be allowed. While Alaska's driving under the influence ("DUI") statute says that defendants may introduce evidence of the amount of alcohol consumed in order to rebut the apparent results of the breath sample, [1] section28.90.020 of the Alaska Statutes (the "working tolerance" statute) ostensibly prevents defendants from introducing evidence of inherent uncertainty in the breath testing procedure. [2] Accordingly, our hypothetical defendant could present evidence that she drank only four beers and that she could not have been higher than .070, but could not present the explanation reconciling the discrepancy: namely, that an apparent result of .080 actually represents a range of possible breath alcohol levels.

This paper argues that the Alaska and United States Constitutions guarantee a criminal defendant the right to introduce exculpatory evidence, and therefore a defendant cannot be prevented by statute from presenting a defense based on the margin of error. [3] As one leading scholar has summarized it, "The Court has rigorously enforced the accused's constitutional right and strictly scrutinized exclusionary rules that block the admission of important defense evidence." [4] Moreover, due process likely requires that known uncertainties in the measuring process be assumed in favor of a criminal defendant.

Alaska courts have generally held statutes unconstitutional when they restrict a defendant's ability to present a defense. [5] For example, in State v. Murtagh, [6] the Alaska Supreme Court considered the validity of a statute that placed a variety of restrictions on criminal defendants seeking to interview witnesses in sexual offense cases (while not placing the same restrictions on the prosecution). [7] Statements taken without following these procedures were presumptively inadmissible. [8] The court held these provisions to be unconstitutional violations of due process. [9] The court went on to note that "the court's responsibility concerning fair trial rights does not mean that the legislature is powerless to act in the area. But our responsibility requires that statutes that are claimed to infringe fair trial rights be closely scrutinized." [10]

Furthermore, "conclusive presumptions" are forbidden in criminal cases. [11] "Permissive presumptions" are permitted so long as the jury is informed that it may but need not conclude that proof of one fact establishes the proof of the second fact, and that such a "permissive inference" in no way relieves the state of the burden to prove each element of a criminal offense beyond a reasonable doubt. [12] Whatever the "working tolerance" statute may mean, however, it cannot establish a conclusive presumption, nor can it shift the burden of proof to a defendant with respect to an element of the offense.


In Alaska it is a crime to knowingly operate a vehicle with a breath alcohol level of at least .080 grams of alcohol per 210 liters of breath, or a blood alcohol level of .08% or more. [13] Under the "blood-alcohol-level theory" of drunk driving (sometimes referred to as the per se theory), the state can convict a person of drunk driving regardless of actual impairment as long as it has chemical tests proving excessive blood or breath alcohol content. [14] In addition to the per se theory, a person can be convicted under the "impairment theory," under which the state can show impairment of driving ability. [15]

The phrase "as determined by a chemical test," which is typically lifted and placed in a jury instruction, [16] is confusing to many jurors (and perhaps even to some courts). For example, in City of Seattle v, Gellein, [17] a Washington trial court instructed the jury that the prosecution had to prove that the defendant was driving and that "at the time he had 0.10 percent or more by weight of alcohol in his blood as shown by chemical analysis of his breath." [18] The jury was unsure what to make of this language and sent a note to the judge asking: "Are we to believe that the breathalyzer test is infallible and accurate? So, if the breathalyzer is .16 then the defendant is guilty because the defendant is driving while he has over .10 percent in his blood stream." [19] The judge gave no clarifying instruction, and the jury found the defendant guilty. [20] The Washington Supreme Court overturned the verdict because the jury may have understood the instruction to require them to accept the apparent breath test result as accurate. [21]

In fact, there are many reasons that a breathalyzer reading may be inaccurate, including equipment malfunction or operator error. In June of 2010, The Washington Post reported that hundreds of defendants in the District of Columbia were wrongfully convicted of DUI because "[t]he District's badly calibrated equipment would show a driver's blood-alcohol content to be about 20 percent higher than it actually was." [22]

Even when a breathalyzer is properly calibrated, the subject sample may not accurately reflect the person's level of sobriety. Most states require two breath samples, [23] and it is common for a person to blow into the breathalyzer twice and obtain one result above .08 and another result below .08. [24]

These deviations are well-known in the scientific literature on breath testing. [25] But two states (Alaska and Delaware) have statutes that appear to forbid introduction of margin of error evidence. [26] For years, Alaska law required that any inherent uncertainty in the breath or blood reading be applied in favor of the defendant, [27] but in 1996 the legislature passed a statute declaring that margin of error evidence in blood-alcohol theory cases was inadmissible. [28] The court of appeals in Mangiapane v. Municipality of Anchorage [29] then held that this statute "effectively declares that a driver violates AS 28.35.030(a)(2) if ... the driver's test result is at least .10 percent blood-alcohol or the equivalent .10 grams of alcohol per 210 liters of breath." [30] In other words, the test result itself was the element of the offense rather than evidence of the offense. The accuracy of the test seems to become irrelevant under this theory.

Within three years, the court of appeals reversed course and clarified that the test only created a presumption of blood or breath alcohol content at the time of offense, and was not itself the element that needed to be proved. [31] However, Alaska courts have not gone back to the requirement that uncertainty must be assumed to benefit the defendant. A defendant cannot challenge the accuracy of the test "as long as a breath test is administered by a properly calibrated instrument approved by the Department of Public Safety." [32]

This line of cases has resulted in considerable confusion as to the elements of DUI. This Article argues that a breath test result should be evidence of a person's breath alcohol concentration rather than an element of the offense. The court of appeals in Mangiapane held that a positive test result was an element of the offense, [33] but succeeding cases have distinguished Mangiapane's holding. [34] Alaska's courts should recognize that due process permits a defendant to introduce evidence...

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