A judge has ruled that a prosecutor can present evidence indicating that a forklift driver had methamphetamine in his system when he turned his vehicle into the path of an oncoming car east of Santa Maria in 2013.

Daniel Castillo

The collision on Philbric Road near Betteravia Road killed two people in the sedan and critically injured two others.

The Friday ruling by Santa Barbara County Superior Court Judge John McGregor came during pretrial hearings in the case against Daniel Castillo, then 37, of Santa Maria .

Castillo is charged with two counts of gross vehicular manslaughter while intoxicated, with special allegations of causing great bodily injury, causing bodily injury to more than one victim and committing a serious offense.

According to the California Highway Patrol, on the afternoon of Aug. 29, 2013, Castillo was driving a large forklift south on Philbric when he attempted to turn left into an agricultural field. The forklift slammed into the side of a northbound Honda Civic, driving it into a drainage ditch​.

Adolfo Pozos Carrasco, 18, of Santa Maria, and a passenger in the rear seat behind him, Casilda Diaz Pozos, 49, of Santa Maria, were declared dead at the scene.

Two other passengers suffered major injuries in the crash.

Castillo’s attorney, Deputy Public Defender Sydney Bennett challenged whether the jury should hear results of tests revealing that her client had methamphetamine in his system and its likely effects on his driving ability.

Cathralynn Cook, a criminologist with the state Department of Justice lab in Sacramento, testified that meth causes poor judgment, increased risk taking, poor attention and more.

“They are unable to focus and easily distracted so they can’t do more than one thing at one time,” Cook said of meth users.

She said experts rely on several factors to weigh whether the discovery of meth in a person might be linked to impairment.

Tests of Castillo’s blood revealed 110 nanograms per milliliter of meth.

“We say anything over 100 nanograms per milliliter is typical of abuse rather than therapeutic levels,” Cook said.

Senior Deputy District Attorney Stephen Foley asked Cook why drug quantity in an individual can’t be measured like blood-alcohol level. She replied that metabolism, how someone takes a drug, the amount of the dose and other factors come into play.

Foley asked Cook to describe her assessment of Castillo’s ability after considering the various factors.

“I believe, yes, he was too impaired to safely operate a motor vehicle,” she said.

Bennett asked whether someone could have that level of meth in his blood, but not be impaired.

“It’s possible, yes,” Cook replied.

After Cook left the witness stand, Foley argued that the jury should hear about the discovery of meth in Castillo’s blood, adding that it led to the defendant’s irrational, reckless and overaggressive actions.

“I think it’s highly relevant,” Foley added.

Bennett argued the blood-work result was not relevant since it didn’t prove impairment. Letting the jury hear the evidence would be prejudicial, she said.

“It’s not relevant in that respect because you can’t look at that,” said Bennett, adding that there is no correlation between a blood test finding drugs in an individual’s system and level of impairment.

But Foley responded that drunken-driving prosecutions began long before the creation of tests to measure blood-alcohol content.

McGregor deemed the evidence relevant to the case, and not prejudicial.

Earlier in the day, attorneys wrapped up the process of selecting a jury and picking alternates.

With pre-trial matters settled, McGregor said opening statements are planned for Monday morning.

Noozhawk North County editor Janene Scully can be reached at jscully@noozhawk.com. Follow Noozhawk on Twitter: @noozhawk, @NoozhawkNews and @NoozhawkBiz. Connect with Noozhawk on Facebook.

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Janene Scully | Noozhawk North County Editor

Noozhawk North County editor Janene Scully can be reached at jscully@noozhawk.com.