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    Wisconsin Lawyer
    January 01, 2015

    Using Preliminary Breath Test Results in Trials? Don’t Hold Your Breath

    The improvement and proliferation of breath-test technology makes it likely more questions will come down the pike regarding the use of preliminary breath test results in the courtroom. Still, it appears that the Wisconsin Supreme Court is determined to keep PBT results out of OWI trials. The trial record in Rocha-Mayo offers a roadmap for prosecutors and defense attorneys when litigating a trial at which PBT evidence will be allowed.

    Rex Anderegg

    breathBreath tests have been used to measure the level of alcohol in the human bloodstream since 1931, the year Dr. Rolla N. Harger, an Indiana University chemist and toxicologist, invented an instrument he gave the rather fetching name of “the drunk-o-meter.”1 While the drunk-o-meter could impound breath in an ordinary rubber balloon during a roadside stop, actual testing of the breath was not immediate. To measure the collected sample for ethyl alcohol, the sample needed to be run through an ascarite tube whose weight before the experiment could be compared to its weight after.2

    It would take another 40 years before breath-testing technology capable of generating quick results came in a small enough package to make full roadside breath testing practical. Thus dawned the era of the now ubiquitous “portable” or “preliminary” breath test, colloquially known by its acronym: the “PBT.” While most people associate PBTs with law enforcement (the main focus of this article), PBTs also are used in a variety of other settings, such as the workplace and hospital emergency rooms.

    To understand the role of the PBT instrument in law enforcement, it is helpful to compare and contrast it with its big sister: the Intoximeter. In the impaired-driving (hereinafter OWI) context, law enforcement officers use the PBT to arrest the suspect, and only later (after transport to the police station) use the technologically advanced Intoximeter to obtain a truly accurate reading of the suspect’s alcohol level.3

    Like most siblings, the two instruments share some traits. Both, for example, begin each test with an air blank, and both purport to sample deep alveolar lung air. Their differences, however, are more instructive for purposes of this article. For one, the Intoximeter is more technologically advanced (for example, unlike the PBT, it employs infrared technology to detect residual mouth alcohol). Equally notable is the more exacting testing protocol the Wisconsin Legislature has mandated for the Intoximeter. These two attributes of the Intoximeter (that is, superior technology and rigorous protocol) largely explain what the attorney will regard as the most critical distinction between the PBT and the Intoximeter: their very different evidentiary uses in the courtroom.

    Breath Testing Protocols

    The testing protocol for the PBT is not complicated. An officer affixes a sanitized mouthpiece to the PBT, engages the instrument, waits for a prompt, and then instructs the subject to blow long enough for the instrument to yield a result. The officer then jots down the result in her field notes and later includes it in her written police report.

    The protocol for an Intoximeter test, by contrast, is much more involved. A valid test on the Intoximeter must be preceded by a 20-minute observation period (to ensure the subject does not burp, belch, regurgitate, and so on). The instrument prompts the officer to have the subject provide two samples, which are automatically sandwiched between additional diagnostic checks, air blanks, and an accuracy check. There must be two adequate, consecutive samples, and they must agree within 0.02 grams for the test to be valid, with the lesser result reported as the useable value. The entire protocol is driven by the Intoximeter’s software and concludes with a printed test card documenting each step of the process for evidentiary use at trial. Additional statutory safeguards ensure instrument operators are well trained and that the instrument’s accuracy is periodically checked and certified.4

    The courts have referred to this veritable cornucopia of safeguards as a legislative quid pro quo for a driver’s implied consent to submit to a breath test when such a sample is properly requested.5 In other words, in exchange for an accurate and reliable test, the driver impliedly consents to provide samples of his breath, or be penalized for refusing, provided a law enforcement officer had probable cause to arrest and request a test of the driver.

    Evidentiary Use of PBTs During Probable Cause Hearings

    As previously noted, the main difference between the PBT and the Intoximeter is how results from the respective instruments can be used in court. PBTs became a fixture in Wisconsin for law enforcement purposes on July 1, 1978, the effective date of then newly created Wis. Stat. section 343.305, a subsection of which allowed law enforcement officers to request a PBT before an OWI arrest.6 Interestingly, the original provision also allowed a motorist’s operating privileges to be revoked for refusing a PBT. That penalty provision was soon repealed, however, when the 1981 legislature again overhauled the implied-consent law and in the process, moved the PBT provision to newly created Wis. Stat. section 343.303, where it has comfortably resided ever since.7

    Rex R. AndereggRex R. Anderegg, U.W. 1989, is a partner in Anderegg & Associates and manages the firm’s Milwaukee office. The firm’s emphasis is in criminal and traffic defense, as well as appellate practice and procedure.

    The primary function of the PBT has remained unchanged since its inception, and its role in OWI cases has always been limited. PBT evidence has always been admissible to establish probable cause to arrest an OWI suspect but never admissible at trial to “prove the person was under the influence of an intoxicant or controlled substance.” This latter role – proving intoxication at trial – has always been the exclusive province of strict protocol, evidentiary tests conducted on instruments such as the Intoximeter. Indeed, the legislature holds Intoximeter tests in such high esteem that it confers on them a statutory presumption of admissibility, accuracy, and relevancy.8

    While PBT results do not enjoy such presumptions, the courts have not required much by way of a foundation for their admissibility, at least during the probable cause (to arrest) hearings they were designed to facilitate. In 2012, in State v. Felton,9 the defendant claimed that admission of the PBT evidence during a probable cause hearing was improper because, contrary to certain administrative code provisions, the state failed to first establish the PBT instrument in question had ever been tested, calibrated, or otherwise approved by the Wisconsin Department of Transportation (DOT).

    The court of appeals disagreed. The Felton court held that although the statutes contain lengthy criteria for the admission of evidentiary breath tests (read, the Intoximeter), no statute similarly preconditions the admissibility of a PBT result when used by law enforcement officers to decide whether to arrest an OWI suspect. Absent “a statute” demanding adherence to certain prerequisites in connection with a blood-alcohol testing device, the proponent need not show compliance with administrative rules.

    Evidentiary Use of PBT Results at Trial

    Given the limited role the legislature charted for PBTs in OWI cases, it came as no surprise when the court of appeals, in State v. Albright,10 confirmed that prosecutors cannot refer to PBT results during OWI trials. Albright, however, left unresolved a nagging question for prosecutors and defense attorneys alike: could PBT results be introduced into evidence during non-OWI trials?

    In 1994, the court of appeals answered that question in the affirmative when it considered, in State v. Beaver,11 whether a defendant could introduce evidence of a PBT result in a sexual assault case. Beaver was convicted of sexual assault partly because of his own statement to police and, during trial, he attempted to introduce the result from a PBT he took in jail immediately after he made an inculpatory statement. Beaver argued the PBT result was relevant to the trustworthiness of his statement (that is, that his quasi-confession was unreliable because he was intoxicated). The circuit court barred the result based on the language of Wis. Stat. section 343.303.

    The court of appeals, however, held the circuit court had erred, reasoning the language and entire subject matter of Wis. Stat. section 343.303 revealed the legislature intended the bar against PBT evidence at trial to apply only to offenses contemplated under that statute, that is, OWI proceedings.12 Five years later, the appellate court confirmed that sauce for the goose was sauce for the gander when it held the prosecution could also use a PBT result against a defendant in a non-OWI trial for battery.13

    OWI Cases: When Law Enforcement Officers Can Lawfully Request a PBT

    Discussion of the next significant development in PBT law requires a brief foray from the courtroom back into the field, because the focus was on what quantum of proof a police officer must have before lawfully asking an OWI suspect to submit to a PBT in the first place. In Jefferson County v. Renz,14 the Wisconsin Supreme Court examined the meaning of the language in Wis. Stat. section 343.303 authorizing police officers to request a PBT when there is “probable cause to believe” a suspect has been operating under the influence.

    The court of appeals, reflecting conventional thought, had interpreted “probable cause to believe” to be coextensive with “probable cause to arrest,” which would have made the PBT an instrument whose primary purpose was to confirm or dispel an officer’s determination that she already had enough evidence (via field sobriety tests, other observations, and so on) to arrest the suspect.15 In other words, if the PBT confirmed the officer’s appraisal of things, the officer would arrest the suspect; if not, ostensibly the officer would let the suspect go.

    Such was not, however, the role for PBTs the Wisconsin Supreme Court gleaned from the phrase “probable cause to believe.” In Renz, the supreme courtheld the phrase has a rather different meaning than “probable cause to arrest,” thereby assigning the PBT a more significant role in OWI enforcement. Probable cause to believe, the courtheld, represented a quantum of proof greater than reasonable suspicion to stop, but less than probable cause to arrest.16

    This created a new burden of proof previously unknown in Wisconsin, and an attempt to explain or quantify it not only is beyond the scope of this article but also would be difficult. Suffice it to say that by creating this new, intermediary burden of proof, Renz transformed the PBT into an instrument whose primary purpose is to bridge the gap between enough evidence to believe the suspect is intoxicated and enough evidence to arrest the suspect.17

    Reliability of PBT Results and Prospective Use During OWI Trials

    Back in the courtroom, the Wisconsin Supreme Court has recently grappled with whether there might be circumstances in which PBT results can be used during OWI trials despite the statutory bar on such use.

    Use by Defendant. The first case was State v. Fischer,18 in which the court examined whether the ban on PBT results in OWI trials must yield to the due process rights of a defendant who needs the result to defend himself or herself. In Fischer, the defendant positioned the PBT result as a critical and irreplaceable data point that, together with his subsequent Intoximeter result, allowed his toxicology expert to generate a blood-alcohol curve. The curve, in turn, was essential to the defense because it demonstrated the defendant was under the legal limit at the time of vehicle operation. Despite positing that the defendant had a Sixth Amendment right to present the evidence in his own defense, the circuit court, relying on the statutory bar in Wis. Stat. section 343.303, refused to allow the PBT evidence, effectively quashing the expert’s testimony.

    In the wake of the Wisconsin Supreme Court’s most recent decision addressing PBTs – State v. Rocha-Mayo – the supreme court seems to be retreating from any blind faith in the PBT’s reliability it might have insinuated.

    The court of appeals affirmed and, again reflecting conventional thought, reasoned the bar on PBT results at trial reflected legislative recognition that such results are not sufficiently reliable for jury consideration in determining guilt or innocence. Discerning a “world of difference” between the PBT and the Intoximeter, the appellate court noted that the PBT instrument is not tested for accuracy either before or after a test, and that the administrative code defines the PBT as a “qualitative” test, while the Intoximeter is a “quantitative” test.19

    Although the Wisconsin Supreme Court unanimously agreed the PBT result must be barred from the trial, it divided 4-3 on the underlying rationale. The minority’s concurrence, authored by Justice Ziegler, and joined by Justice Roggensack and Justice Gableman, opined that PBT results are unreliable and inadmissible “as a matter of law” when offered for the purpose of confirming or dispelling a defendant’s specific alcohol concentration in an OWI or operating with a prohibited alcohol concentration (PAC) trial.

    The majority, however, went in a rather different direction, seemingly averse to voicing any criticism of the PBT’s reliability. While conceding disputes could center on the PBT’s accuracy, the majority reasoned the legislative bar did not stem from reliability concerns at all and noted the PBT was reliable enough for other law enforcement purposes. Instead, the majority reasoned, the legislature barred PBT results from OWI trials because doing so would make it more likely that OWI suspects would consent to the test (ostensibly because they would be aware of its inadmissibility at trial).

    Echoing Renz, the court in Fischer noted that by securing cooperation when an officer has a reasonable basis to stop a suspect, but not yet probable cause to make an arrest, the bar on PBTs was meant to serve the public policy of promoting prompt, efficient OWI investigations. The Fischer court concluded that this important state interest (under the requisite balancing test when due-process rights square off against state interests) outweighed the defendant’s interest in presenting PBT evidence.

    Attorneys should note, however, that the supreme court’s opinion in Fischer was not the last word on the matter, because the defendant then successfully petitioned the federal district court for a writ of habeas corpus. In Fischer v. Ozaukee County Circuit Court,20 the U.S. District Court for the Eastern District of Wisconsin refereed a different outcome between the clash of the titans (that is, drunk driving enforcement versus the Sixth Amendment). While not disputing the compelling state interest in arresting and convicting drunk drivers, the district court was skeptical of how the PBT bar would serve that interest, particularly in light of the decision in Renz. The district court found it difficult to reconcile Fischer’s reasoning (that the legislature created the prohibition to give OWI suspects an incentive to submit to a PBT) with Renz’s holding (that PBTs bridge the gap allowing OWI suspects to be arrested). Were such really the case, the district court mused, an OWI suspect “will almost always be well-advised to literally keep his mouth shut and his breath out of a PBT.”

    In short, if the Wisconsin Supreme Court was correct about legislative intent in both Renz and Fischer, those cases were working at cross-purposes. And because the evidentiary rule resulted in a significant diminution of the right to present a defense, which called into question the integrity of the fact-finding process, it required close scrutiny. That, in turn, led the district court to conclude that the Sixth Amendment trumped Wis. Stat. section 343.303 under these circumstances, and that excluding the defense expert’s testimony was thus an unreasonable application of Sixth Amendment law.

    The district court noted its decision was consistent with the idea that the legislature had no concern with PBT reliability and indeed, if the PBT were reliable, the reliability would only enhance the probative value of the alcohol curve the defendant wished to present. Nevertheless, in the wake of the Wisconsin Supreme Court’s most recent decision addressing PBTs – State v. Rocha-Mayo21 – the supreme court seems to be retreating from any blind faith in the PBT’s reliability it might have insinuated.

    Test Not Administered by Law Enforcement Officer. Rocha-Mayo arose from a PBT administered in an emergency room (ER) for diagnostic purposes after an auto accident in which the defendant was injured and another motorist was killed. The attending ER doctor smelled alcohol on the defendant and instructed a nurse to administer a PBT. Using a PBT instrument that happened to be a model approved for law enforcement in Wisconsin, the nurse obtained a single sample registering 0.086, barely above the legal limit. The defendant was charged with homicide by intoxicated use of a motor vehicle.

    The circuit court allowed thestate to use the 0.086 result at trial, which notably was a proceeding, in the words of Wis. Stat. section 343.303, “in which it [was] material to prove the person was under the influence of an intoxicant or controlled substance.” The circuit court reasoned the section 343.303 bar was not implicated because the PBT had not been administered by a law enforcement officer, which, it further reasoned, was the only context that Wis. Stat. section 343.303 was designed to address. More striking still, the circuit court instructed the jury it could find the defendant was intoxicated based solely on the PBT result although it need not do so (a breath test instruction typically reserved only for the Intoximeter). In an unpublished decision, the court of appeals affirmed.

    PBT evidence has always been admissible to establish probable cause to arrest an OWI suspect but never admissible at trial to “prove the person was under the influence of an intoxicant or controlled substance.”

    The Wisconsin Supreme Court affirmed the conviction, but because there were four separate opinions, some work is needed to decipher the decision’s import. Perhaps the most remarkable feature of Rocha-Mayo is that despite the fact that six justices agreed it was error to allow the prosecution to introduce a PBT result into evidence at an OWI trial, Rocha-Mayo cannot be cited for that proposition. The linchpin of this odd outcome was a majority opinion authored by Justice N. Patrick Crooks, who emphatically “assume[d], without deciding, that the circuit court erred”(a form of the phrase appears eight times in the opinion) but then deemed the error “harmless.” Justice Crooks was joined in his harmless-error analysis by Justice Ziegler, Justice Roggensack, and Justice Gableman, but they again wrote a separate concurrence to reaffirm their Fischer concurrence that PBT results are inadmissible as a matter of law. For the concurrence, it had been actual error to allow the PBT result at Rocha-Mayo’s trial, but like Justice Crooks, they agreed the error had been harmless.

    Rocha-Mayo also featured two separate dissents, but only the one authored by Justice Prosser is of interest here. Justice Prosser (joined by Chief Justice Abrahamson and Justice Bradley), said, as did the concurring justices, that the circuit court had erred in allowing the PBT evidence. While not deeming the evidence inadmissible “as a matter of law,” Justice Prosser did reason that “the admission of the PBT result [did] not fit within any plausible exception to the statutory directive and [came] with few of the protocols that assure the integrity and reliability of the tests authorized by Wis. Stat. §343.305(3)” (that is, the Intoximeter).

    There was thus plenty of common ground between the concurrence and the dissent, because both found actual error and did so based on the legislative distinction between the PBT and the Intoximeter. Because the dissent vigorously rejected the idea the error was harmless, however, a majority could not be formed on that front. In the end, harmless error ruled the roost, and a majority barring prosecutors from introducing PBT evidence in these circumstances never hatched.22


    The improvement and proliferation of breath-testing technology makes it likely more questions will come down the pike regarding the use of PBT results in the courtroom. A burgeoning number of motorists now have court-ordered ignition interlock devices installed in their vehicles. There has been some discussion among automobile manufacturers regarding factory-installed devices of this nature. The first IntoxBox was recently installed in a Wisconsin tavern; the device allows patrons, for a small fee, to blow and check their blood-alcohol level before deciding whether to drive home. Other individuals now have their own PBTs for precisely that purpose.

    All these uses involve situations in which breath tests are not administered by law enforcement officers. Whether the different context takes the matter outside the purview of Wis. Stat. section 343.303 (as the circuit court in Rocha-Mayo ruled) and whether that should end the inquiry are questions that remain unsettled. Uncertainty springs from the absence of a unified and consistent rationale from the Wisconsin Supreme Court as to why the legislature banned PBT results from OWI trials.

    Nonetheless, at least one theme emerges. The supreme court appears determined to keep PBT results out of OWI trials, albeit perhaps more determined when a defendant (as opposed to the prosecution) proffers the evidence. Fischer, after all, unanimously refused to sanction a defendant’s use of a PBT result, while in Rocha-Mayo, the supreme court could not even muster a majority to clearly make the same point when the prosecutor is the PBT proponent. All of which creates an interesting dynamic moving forward.

    Prosecutors would still probably be well advised not to travel the Rocha-Mayo road and attempt to use PBT evidence against defendants during an OWI trial simply because the test was not administered by law enforcement. Although defense attorneys cannot cite Rocha-Mayo as binding precedent prohibiting such use, they can point out that six of the seven supreme court justices opined that such would be error. In the meantime, Wis. Stat. section 343.303 will continue to present an absolute bar when the sample has been collected by law enforcement officers.

    The dynamics will be somewhat different when defendants attempt to use PBT results as part of their OWI trial defense. Under such circumstances, prosecutors need only cite Fischer to block the attempt, because federal court decisions are not binding on the Wisconsin Supreme Court (with the exception, of course, of those issued by the U.S. Supreme Court).23 Defense attorneys, on the other hand, may wish to frame the issue in Sixth Amendment terms, thereby preserving that constitutional issue for defendants willing and able to take the long and winding road to federal court. It should be noted that federal habeas relief is available only to petitioners who are “in custody” and accordingly, such a strategy will not be viable for civil first-offense OWI cases, and might not be viable for second and subsequent offense cases unless the defendant receives a lengthy sentence or counsel obtains a stay of sentence pending appeal (as happened in Fischer).

    Some final thoughts might be helpful for any attorney litigating a trial at which PBT evidence will be allowed. In such cases, one side will have an interest in presenting the PBT as a reliable and accurate instrument, while the other will wish to convince the jury of precisely the opposite. To that end, the trial record in Rocha-Mayo offers a good roadmap for prosecutor and defense attorney alike.

    To support the reliability of the PBT instrument, and therefore any test results from that instrument, the state called as witnesses both the CEO of the instrument’s manufacturer and the chief of Wisconsin’s Chemical Test Section. The defense countered with its own expert, and an effective cross-examination as to the instrument’s limitations vis-a-vis the Intoximeter, a comparative analysis that appears especially apropos in the wake of Rocha-Mayo.

    In any event, whether such a battle materializes will largely and likely be driven by other questions and practicalities. How crucial is the PBT result to the proponent’s case? What is the applicable burden of proof? Is the PBT instrument in question a model approved for use in Wisconsin? What resources are available to devote to the PBT issue? However counsel resolves these issues and ultimately formulates trial strategy, it should be done with knowledge that the reliability of the PBT is subject to attack. It is certainly not the gold standard for breath testing in Wisconsin, and there is room to argue that it is not even entitled to a bronze.


    1 See, e.g., State v. Fischer, 785 N.W.2d 697 (Iowa 2010).

    2 See, e.g., City of States v. Warren, 252 P.2d 781 (Ariz. 1953).

    3 The Intox EC/IR II is a bench-top instrument featuring fuel-cell-integration analysis combined with real-time analytical infrared technology. For purposes of convention, the instrument will be referred to throughout this article as “the Intoximeter.”

    4 Wis. Stat. section 343.305(6)(b) requires the DOT to approve techniques and methods for performing chemical analysis of the breath and to that end 1) approve training manuals and courses for law enforcement in the chemical analysis of a person’s breath; 2) certify the qualifications and competence of individuals conducting the analyses; 3) have secretary-approved trained technicians test and certify the accuracy of the equipment to be used by law enforcement officers for chemical analysis of a person’s breath before regular use of the equipment and periodically thereafter at not more than 120-day intervals; and 4) issue permits to individuals according to their qualifications. See also Wisconsin Admin. Code §§ Trans 311.03, 311.04, 311.06.

    5 State v. Grade, 165 Wis. 2d 143, 148-49, 477 N.W.2d 315 (Ct. App. 1991).

    6 Chapter 193, §7, Laws of 1977.

    7 Chapter 20, Laws of 1981. The most important change in the statute was the creation of per se alcohol violations, the so called PAC offense.

    8 Wis. Stat. § 885.235(4).

    9 State v. Felton, 2012 WI App 114, 344 Wis. 2d 483, 824 N.W.2d 871.

    10 State v. Albright, 98 Wis. 2d 663, 675, 298 N.W.2d 196 (Ct. App. 1980).

    11 State v. Beaver, 181 Wis. 2d 959, 970, 512 N.W.2d 254 (Ct. App. 1994).

    12 Id. at 969. Beaver went on to hold the evidence properly was barred on other grounds. Id. at 970-71.

    13 State v. Doerr, 229 Wis. 2d 616, 622, n.1, 599 N.W.2d 897 (Ct. App. 1999).

    14 County of Jefferson v. Renz, 231 Wis. 2d 293, 603 N.W.2d 541 (1999).

    15 County of Jefferson v. Renz, 222 Wis. 2d 424, 588 N.W.2d 267 (Ct. App. 1998).

    16 See County of Jefferson v. Renz, 231 Wis. 2d at 315-16.

    17 Chief Justice Abrahamson examined the difficulty in distinguishing between the various burdens of proof in criminal and traffic cases in her concurrence, which includes a helpful diagram for the practitioner. See 317-27.

    18 State v. Fischer, 2010 WI 6, 322 Wis. 2d 265, 778 N.W.2d 629.

    19 State v. Fischer, 2008 WI App 152, ¶¶ 13-17, 259 Wis. 2d 799, 656 N.W.2d 503. As a “quantitative” instrument, the PBT is well suited for trials at which the presence or absence of alcohol is the operative issue, such as underage-drinking and bail-jumping cases and probation violations.

    20 Fischer v. Ozaukee Cnty. Circuit Court, 741 F. Supp. 944 (E.D. Wis. 2010).

    21 State v. Rocha-Mayo, 2014 WI 57, 355 Wis. 2d 85, 848 N.W.2d 832.

    22 The other issue in Rocha-Mayo – whether a PBT deserves a presumption of reliability vis-a-vis a jury instruction – was left on the cutting room floor. The dissent opined the instruction was erroneous. There can be little doubt the concurrence would agree, but it simply joined Justice Crooks’ “assumption” of that error, without addressing it. 

    23 See, e.g., State v. Mechtel, 176 Wis. 2d 87, 94-95, 499 N.W.2d 662 (1993).

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