By Scott North

Herald Writer

Evidence in hundreds of drunken driving cases in south Snohomish County will be allowed at trial after a judge’s ruling Thursday turning down a challenge to breath-test results.

Prosecutors feared that questions about record-keeping and thermometers in the machines used to test for intoxication could lead to problems, and perhaps dismissals, in hundreds of cases, deputy prosecutor Charlie Blackman said.

That’s what happened in King County after judges suppressed breath-test results, potentially affecting thousands of defendants.

But a ruling by South District Court Judge Stephen Dwyer closed off that line of attack, at least in Snohomish County’s south end, Blackman said.

Thursday’s ruling does not directly affect drunken-driving cases in the county’s other district courts in Everett, Monroe and Arlington.

The ruling came after the judge heard five days of pretrial testimony for three defendants, all of whom argued that evidence against them was questionable and should not be allowed at their trials.

"None of these defendants has met his burden of proving that he has been deprived of evidence such that his ability to present a defense has been vitiated or impaired," Dwyer wrote. "All relevant facts have come to light. The defendants have used evidence of these facts in the pretrial proceeding and may use evidence of these facts at trial."

The Washington State Patrol, which maintains all breath-test machines in the county, learned in November 1999 of potential discrepancies in the accuracy of thermometers used in the breath tests. The patrol replaced the thermometers but didn’t always keep good records about any problems they found.

Through random testing, patrol technicians learned that about 30 to 40 percent of the standard thermometers were inaccurate. The accuracy of sobriety test results hinge in part on the accuracy of thermometers that are part of the testing machines.

You can call Herald Writer Scott North at 425-339-3431

or send e-mail to north@heraldnet.com.