A statute (and related regulation) says that you can't drive with a blood alcohol content of .08 or more. When a chemical test says that your number is .08 or above, that creates a rebuttable presumption that you've violated the law.
A guy gets stopped and blows a .08. His expert testifies, without rebuttal, that the particular test used here has a range of .02; in other words, that someone who blows a .08 might actually have a .06 (or .10). The trial court credits that expert's testimony and, on that basis, concludes that there's insufficient evidence that the guy actually drove with .08 or more.
The Court of Appeal reverses. It holds that since the regulations allow the particular testing device used here, to hold otherwise would conflict with this approval and require everyone to essentially blow a .10 rather than a .08.
It's an interesting holding. My first thought was that it was silly. The mere fact that a device is approved doesn't mean that its results are automatically valid, much less precise. After all, everyone admits that the guy might well have driven with a .06. The Court of Appeal's holding essentially rewrites the statute to say that it's illegal to drive with a .06 or more as long as a particular test says that it's a .08. Plus it inherently means that some individuals who are in fact innocent will be found guilty. Imagine, for example, that the .06-.10 range is evenly spaced; in other words, of those who the test kicks back a .08, twenty percent actually have a .06, twenty percent have a .07, etc., all the way up to a .10. That means that the Court of Appeal's holding will result in innocent people being found guilty 40% of the time. Wow. That just seems way, way too much. The whole ten (or a hundred) guilty people going free before one innocent person is convicted and stuff.
But my second thought was, well, if the Legislature feels like doing that, it can, right? Which arguably is exactly what it did when it created the presumption. My complaint, I thought, is perhaps with the presumption, not the Court's holding. And the presumption is rebuttable, after all. So maybe the only thing the Court is saying is that if the only thing you have is the inherent error, that doesn't suffice to rebut the presumption. Mind you, that will result in all the untoward consequences I identified. But that's a complaint to the Legislature, not the Court. Maybe that's right.
But then my mind went off on a third tack. Okay, so if the way to defend the Court's holding is to focus on the statutory presumption (and I think that's indeed the only way one could defend it), then what are we really accomplishing here? Presumably in the vast majority of cases there's something other than the mere expert's testimony. The testimony of the police officer in what she saw, the testimony of a defendant as to how much he drank, etc. Imagine that the officer says that the guy blew a .08, the expert testifies that there's a .02 range, and the defendant says (as I imagine they all would) that "I felt fine. I only had two or three drinks." At that point, it seems to me that the presumption doesn't do the work required to sustain a guilty finding. Everyone admits the .08 could be a .06. There's some evidence (from the defendant) that it was actually a .06 and .07. And we know that it's true a huge number of times; if the error is linear, as much as 40% of the time. At that point we'd have to acquit, right? Prompting all the consequences the Court of Appeal flees from. (As well as making even more dubious its decision to review this stuff de novo rather than for substantial eveidence.)
So my last thought is either that the Court of Appeal's decision is either dubious or holds only in the rare case in which there's no evidence at all other than the test results. Which is perhaps what it should be. Because we should be wary, I think, of convicting and punishing innocent people. Even if doing so advances administrative ease.