City of Seattle v. Ludvigsen

*663¶1

Chambers, J.

In 2002, Mark Ludvigsen was arrested on suspicion of driving while intoxicated. At that time, if the city of Seattle (City) wanted to convict Ludvigsen under the “per se” prong of its former driving while intoxicated ordinance,1 it had to prove Ludvigsen failed a valid breath test. The breath testing machine compares the amount of alcohol vapor in a known sample with the alcohol vapor in a breath sample at a known temperature. In 2002, to establish that the test was valid, the government had to prove that the test machine’s thermometer had been certified by a thermometer…