MN Supreme Court Backs Reasoned Requests For Breathalyzer Source Code

viralMeme writes with news that the Minnesota Supreme Court has upheld the right of drunk-driving defendants to request the source code for the breathalyzer machines used as evidence against them, but only when the defendant provides sufficient arguments to suggest that a review of the code may have an impact on the case. In short: no fishing expeditions. The ruling involves two such requests (PDF), one of which we've been covering for some time. In that case, the defendant, Dale Underdahl simply argued that to challenge the validity of the charges, he had to "go after the testing method itself." The Supreme Court says this was not sufficient. Meanwhile, the other defendant, Timothy Brunner, "submitted a memorandum and nine exhibits to support his request for the source code," which included testimony from a computer science professor about the usefulness of source code in finding voting machine defects, and a report about a similar case in New Jersey where defects were found in the breathalyzer's source code. This was enough for the Supreme Court to acknowledge that an examination of the code could "relate to Brunner's guilt or innocence."

Comments

Fishing expeditions

[Brian Gordon]

So essentially challenging evidence gathering methods is insufficient, but making colorful posters and waving around a PhD is fine?

Re:Fishing expeditions

[houstonbofh]

So essentially challenging evidence gathering methods is insufficient, but making colorful posters and waving around a PhD is fine?

Yes. Like a slashdot legal opinion is worthless, and someone who has passed the bar has value. Who is questioning the procedure is relevant.

Re:Fishing expeditions

[Bruce Perens]

I've never found it very difficult to understand the lawyers and judge's case findings. Yes, they use a little Latin, but you can learn the 100 most used words and look up anything more that comes up on the web. And they cite cases, which you can look up too.

Are you talking about contracts?

Re:Fishing expeditions

[Dhalka226]

I remember a discussion about this on /. awhile ago, and somebody brought up a point I couldn't quite remember. I hopped over to the wikipedia page to look for something about found this:

"Some breath analysis machines assume a hematocrit (cell volume of blood) of 47%. However, hematocrit values range from 42 to 52% in men and from 37 to 47% in women. A person with a lower hematocrit will have a falsely high BAC reading."

and this:

"Breathalyzers assume that the subject being tested has a 2100-to-1 'partition ratio' in converting alcohol measured in the breath to estimates of alcohol in the blood [. . .] However, this assumed 'partition ratio' varies from 1300:1 to 3100:1 or wider among individuals and within a given individual over time."

I'm not sure what, exactly, I was remembering from the previous discussion; these may or may not be it. What I do remember is that it was essentially that, somewhere in this code, there are assumptions made and that the validity of the assumptions is going to directly affect the validity of the code.

Without knowing what, exactly, this machine is measuring and what it is assuming about the individual taking the test, it's impossible to know whether or not there's any reason to believe the test was inaccurate. Since both of these people argued this case to the Minnesota Supreme Court, I hope they both feel they're innocent.

I suppose this guy's lawyer should have made that argument. On the other hand, I don't think it's unreasonable for judges who are going to oversea DUI cases to understand that a breathalyzer is not, by any stretch, conclusive evidence. Use it to haul somebody in, by all means -- then get yourself a blood test. Bill the person being charged for the test for all I care. The breathalyzer itself should not be admissible in court. (I'm ignoring, by the way, the fact that something like having taken cough medicine could also affect the results.)

Re:Hm.

[spun]

That is mentioned as a consequence of the ruling. Now it remains to be seen whether the manufacturer will release the source code. If they won't, presenting a copy of Bruner's exhibits will be a 'get out of jail free' card for drunk driving in Minnesota. Which will mean the state will have to go with a manufacturer that WILL provide the source. Nice.

My father wrote the first Felony DWI laws in MN

[cenc]

Thought I would share this, and before a bunch of you start posting BS about the claim of who wrote what, that is not the point. The point is the evolution of MN DWI law and technology.

My father as a prosecutor in Minneapolis in the 60's and 70's started prosecuting drunk drivers for things like felony manslaughter and such. At the time it was just misdemeanor, and often the police would just give someone a ride home. The State legislators and several lobby groups caught wind of it and asked him to write the laws. Those became the first felony laws for DWI in MN, and later where used as a model for other States around the country. Obviously they have been super modified since then, but the fundamental principle that DWI is something serious is still there.

My father went on in private practice as defense attorney in the 80's. Almost all of his acquittals on DWI came down to discrediting the probable cause (i.e. the officer) for the arrest in the first place. Typically the officer's judgment was always front and center (e.g. did he really see him cross the center line on an ice covered road). It got progressively harder as they started adding video cameras and other technology to get someone off on a DWI charge, as the officer's judgment became less important.

I suspect since my father's time, the only thing left to really attack is the validity of the technology itself that measures the crime.