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California DUI Tests Increasingly Challenged By Defense Lawyers

SAN FRANCISCO (KPIX 5) -- Defense attorneys throughout California are starting to use a new legal challenge against drunk driving, which has led juries to acquit drivers charged with DUI.

Peter Johnson, a criminal defense attorney from Walnut Creek, has used the challenge. "It's nothing something that's a trick or something that defense attorneys might get accused of. It's legitimate science," he told KPIX 5.

Johnson argues the current way the blood alcohol level is protected is outdated because it's just an estimate and is not scientifically sound. While he hasn't had a judge throw out the blood alcohol results, Johnson said he has had jurors acquit his clients of DUI charges.

"They understand what was being conveyed and established it with the other jurors and established that in fact there was reasonable doubt," Johnson said.

Santa Clara County Deputy District Attorney Chris Boscia said he faced this new defense in court. He said, "The basis of that challenge was that we weren't doing the best science."

In order to get acceptable scientific numbers, Boscia said the forensic equipment in Santa Clara County was certified to meet international standards.

Boscia said he is concerned the new defense strategy will undermine DUI prosecutions because most California county labs aren't yet certified.

Boscia says, "What could happen is that people who are truly driving under the influence could get off, based on this tactic."

To prevent drunk drivers from getting off scot free, most California forensic labs are now planning to be certified by the end of this year.

There is still no guarantee the defense won't find a way to fight that as well. Johnson said, "There's always a way to challenge the evidence."

(Copyright 2013 by CBS San Francisco. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed.)

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