Here’s that DUI case we alluded to last week.
It’s based on a driver’s challenge to his license suspension after his arrest. His post-arrest blood test showed a blood-alcohol concentration (or BAC) of 0.23 percent. He challenged this finding at the DMV’s administrative hearing and lost. He then petitioned the superior court to overturn that finding and lost again.
After twice losing before the agency and the trial court, he took another swing in the court of appeal, and there, he won.
The issue was whether his blood-test result was reliable.
The crime lab had tested his sample using a machine called a gas chromatograph. It has a heated chamber with two columns through which a sample is passed in gaseous form, and therein lies the rub. You’ve got to use both of those columns. One isn’t enough. Otherwise, you may get a false positive or the machine may indicate more alcohol than actually exists.
According to the driver’s expert and even the machine’s own manufacturer, one column could “tentatively identify” alcohol but “simply [could not] confirm its identity” or “how much might be present.”
In this case, the lab used the right machine, but the test results showed data from only one column, and the DMV didn’t offer any proof to show otherwise.
Thus the DMV could not rely on the test results because, as a matter of scientific principle, one column’s result was incapable of establishing the driver’s BAC.
And so the court of appeal reversed.