Minnesota Supreme Court limits challenges to breathalyzer tests

People who are or were arrested for drunk driving in Minnesota lost a bid today to fight their charges on the basis of errors in the instrument used to administer breathalyzer test.

The Intoxilyzer 5000EN uses infrared absorption spectroscopy to measure the breath alcohol concentration of subjects who provide breath samples. But last year, Minnesota acknowledged there’s a problem with the source code in the unit, prompting Minnesotans to start challenging their arrests.

Today, a sharply divided Minnesota Supreme Court turned aside the challenges, upholding a district court finding based on a state’s expert witness that the instrument “produced valid breath alcohol measurements and functioned as designed.”

But nearly a half-dozen other experts concluded otherwise when the district court held a hearing. But in his opinion today, Justice Barry Anderson dismissed those claims. “Based on this record, we conclude that a preponderance of the evidence supports the district court’s pretrial determination that Intoxilyzer 5000EN instruments that report a numerical value for measured breath alcohol are reliable and unaffected by the source code errors alleged at the evidentiary hearing.”

“I have concerns regarding the practical effect of these rulings to the extent they essentially eviscerate the opportunity for an accused to challenge the weight or credibility of Intoxilyzer 5000EN results,” Justice Alan Page wrote in a dissenting opinion. He says even the proximity of a cellphone at the time of the test could influence the results, but a person charged with drunk driving couldn’t full admit into evidence the reliability of the breathalyzer.

“The practical result of the court’s holdings is that defendants will be unable to challenge Intoxilyzer 5000EN results,” Justice Page said. “Despite evidence that the test has a margin of error, that radio frequencies from cell phones can disturb the accuracy of the test, and that the test may erroneously produce a deficient sample,4 a defendant may not raise the source code as a potential cause of an inaccurate or deficient sample. Denying the accused an opportunity to raise source code issues effectively eliminates the accused’s opportunity to challenge the results.”

Two other justices — Helen Meyer and Paul Anderson — joined in Page’s dissent.

The full opinion is here.

  • Jim Shapiro

    Good. This is a move in the right direction.

    In what percentage of cases is a driver asked to blow into a breathalyzer when they haven’t been drinking?

    How would permitting intoxicated drivers to get off on a technicality be a good thing?

  • matt


    I would agree with your sentiment except the consequences are quite severe for DWI. Criminal record, loss of driving rights, higher insurance costs and a tougher time finding a job. So if you had three drinks over 3 hours and a blood test would peg you at .06 and the breathalyzer puts the number at .09 what does that technicality cost you? I get the whole don’t drink and drive – period – it makes sense and should be followed. But I also realize there is a difference between driving through empty residential streets at 11:00 p.m. with a BAC of .09 and cruising on the highway at rush hour at .14 but the law does not recognize that difference so the best that we can hope for are small cracks that let a judge and or jury alleviate the blunt force of a one size fits all law. If technicalities allow for that to happen and wise jurists are left with that discretion our society is better off.

  • John P.

    The court has determined that the “preponderance of evidence” says the Intoxilyzer 5000EN results are valid. I do not have any better information than they do.

    The way the law is structured is not fair, and that is the legislators problem, not the courts. The difference between impaired and not impaired is not the difference between .078 and .081, it is a continuum above and below and the law should reflect that beginning with a hand slap training class with no record at something well below .08 and progressing to felonies. Every measurement has a margin of error, and this would make the accuracy of the machines less critical.

  • Jim Shapiro

    Matt – Well said. Thanks for providing the articulate, logical, fact-based counterargument.

    Thus making it a heart vs head issue. For me anyway.

    I’m also concerned about the lack of evidence regarding a preponderance of “wise jurists”.

    Both of which are reasons that I ran screaming from law school. 🙂

  • BJ

    As a software developer the fact that the company who makes the device would not let anyone see the source code is a MAJOR problem.

    “source code errors alleged ”

    My code is always perfect.

    check out:

    French rocket Ariane 5.

    US Mariner 1

  • http://www.georgecreal.com George Creal

    Deciding that the machine is reliable “by a preponderance of the evidence” may be the correct legal standard for this particular proceeding

    but says little more than the machine is probably reliable, more likely than not reliable, or more than 50% of the credible evidence suggest is reliable and is hardly a ringing endorsement. What happened to “beyond a reasonable doubt” standard applicable in criminal cases?

    More troubling due process issues in the form of the right to confront witnesses called against you and the right to a thorough and sifting cross-examination concerns are presented by the Intoxilyzer 5000, when a State enacts a statutory scheme in which:

    (1) evidence usually determinative of the defendant’s guilt (e.g., blood alcohol content in a per se DUI prosecution) is tested and reported, not by forensic experts who testify and face cross-examination on the reliability of their methods and the accuracy of their results, but rather by a machine (e.g., the Intoxilyzer 5000) that takes in a specimen from the defendant and, through internal mechanisms and computer code, generates a test report;

    (2) the machine’s computer code is unavailable to the defendant through discovery or compulsory process because the State avoids possessing outside of a civil proceeding to determine its reliability;

    (3) the machine’s test result is admissible at trial through a witness who can say that he was qualified to operate the machine and it operated as designed, but who has no knowledge about whether the machine was in fact designed to produce reliable and accurate results under the circumstances presented; and

    (4) the machine uses up the specimen, with nothing maintained for later confirmation or independent testing.

    I am not a Minnesota lawyer nor I have studied the Minessota decision carefully other than following new media reports, but as we say in Georgia “that hardly seems fair.”

  • Michael

    “In what percentage of cases is a driver asked to blow into a breathalyzer when they haven’t been drinking?”

    If we already knew beyond a shadow of a doubt that the driver is drunk before we ran the test on the driver, we wouldn’t need a test! Since we don’t know, the test is there — And if we test, it has to assume that some are not drunk even though they’re being tested (again, or else we wouldn’t be testing at all).

    And, from there, if the machine is potentially wrong, but is deemed infallible by this artificially conceived court ruling based on a controversial expert’s opinion, and we have no way to actually check the validity of the results this machine puts out, we have put ourselves into law by fantasy. No longer a rule of law, but a rule of machine.

    What a terrible decision.

  • MikeB

    Incredible that a machine is always deemed reliable in matters of determining guilt or innocence. Once the courts have decided that the machine’s results cannot be challenged, what is the incentive for quality here on out? How do we know they are working 2 years from now? The manufacturer is now unaccountable for its products’ results.

    A terrible decision.