Jury Duty: Day Seven - The Verdict

The pulse races when you read a guilty verdict to a defendant. You are very much aware that you are defining a significant portion of a life's trajectory. And the court reminds you of this act, by asking each juror to verbally confirm the verdict.

Last Friday, I voted guilty to convict a defendant accused of two counts: driving under the influence, and driving with a blood alcohol level of .08% or above. Until I voted guilty, the jury was hung, with myself voting against the rest.

I wasn't convinced that the prosecution's case was strong enough, as the field sobriety tests were inconclusive, the field breathalyzer was unreliable, and the defendant's reading at the station breathalyzer was well within the stated margin of error.

What changed my mind was actually looking at the prosecution's exhibits. Buried within a stack of papers were the calibration records for both the field and station breathalyzers. Looking at the numbers yielded some telling findings. First of all, the field brethalyzer's deviation from normal was about .013 grams per 1000ml - for the sake of discussion, we could suppose that the unit was overstating the defendant's blood alcohol content by .013 on a reading of .099. Which places the defendant well above legal limit.

But what if you throw out the field breathalyzer (as you should, since the unit died with two weeks of the field test)? Well, it turns out that the prosecution wildly overstated the margin of error for the station breathalyzer, much to the detriment of its case. The prosecution stated that the margin of error for the station breathalyzer was + or - .01. But a quick perusal of the station's calibration logs reveals that the machine never deviated from a test sample by more than .001. In other words, the machine was a whole order of magnitude more accurate than the prosecution claimed. The defendant's reading of .08 was almost certainly a .08.

The practically infallible accuracy of the station breathalyer established (for myself) the defendant's guilt beyond a reasonable doubt. So I changed my vote. And we ended jury deliberations after an hour.

We almost made minimum wage that day.