FAIRFIELD — A DUI defendant has not been denied the right to a speedy trial and the case doesn’t involve a driver charged with driving under the influence of caffeine, the Solano County District Attorney’s Office says.

The District Attorney’s Office in a Friday court filing disputed defense attorney Stacy Barrett’s assertion that delays warrant dismissing the case against her client, Joseph Schwab, 36, of Fairfield.

A Tuesday statement from the prosecution said the District Attorney’s Office is continuing to investigate the case by consulting with experts to determine what substance contributed to Schwab’s alleged impaired driving.

An agent with the California Department of Alcoholic Beverage Control was driving northbound on Interstate 680, south of Gold Hill Road in Fairfield, when a vehicle swerved in her lane and almost collided with her, the District Attorney’s Office said in the statement Tuesday.

The ABC agent saw the driver weaving in and out of traffic and almost cause several collisions Aug. 5, 2015, the District Attorney’s Office said, and the agent stopped the car driven by Schwab, who was described as highly agitated, “amped up” and with pupils that were dilated.

The agent noticed workout supplements in the vehicle and administered standardized field sobriety tests to determine impairment, the District Attorney’s Office said. She believed Schwab was too impaired to drive, the District Attorney’s Office said.

He was arrested on suspicion of misdemeanor DUI and reckless driving.

The agent offered Schwab a drug recognition evaluation but he declined, the District Attorney’s Office said.

Defense attorney Barrett said Schwab was offered the drug evaluation at the jail after his arrest – and after he’d undergone a series of field sobriety tests along with a preliminary alcohol screening test that showed him with a 0.00 percent blood-alcohol level, Barrett said.

“I’m done,” Schwab responded, Barrett said.

The District Attorney’s Office in its release Tuesday said Schwab had agreed to submit to a blood test and the blood sample was submitted to the Solano County District Attorney’s Office Forensic Laboratory for testing.

Results were negative for the standard drugs screened and results for a blood sample sent to a laboratory out of the area were negative for the standard drugs tested but positive for caffeine, said the District Attorney’s Office, which said that the blood sample was not tested for all known drugs.

Barrett said Tuesday she doesn’t know how the district attorney expects to prove her client drove under the influence when tests have produced only caffeine.

“There’s no evidence of anything else in his system,” she said.

The 10-month delay between Schwab’s August 2015 arrest and the filing of charges in June 2016 is unusual, the attorney said, and complicates trying to defend the case. Her Dec. 16 motion to dismiss the case for lack of a speedy trial is set to be heard Jan. 3 in Solano County Superior Court.

Schwab’s DUI trial is scheduled for Jan. 11.

The District Attorney’s Office in the Tuesday release said although it is difficult to prove impaired driving without a toxicology result, the ABC agent is qualified as an expert in drug recognition evaluation and did form the opinion from the defendant’s driving, appearance and demeanor – and performance of field sobriety tests – that Schwab’s ability to drive a vehicle was impaired.

Barrett, in an interview Tuesday on KFI radio in Los Angeles about the case, said the ABC agent was driving in an unmarked car along I-680 when the August 2015 incident occurred.

The case has spurred media coverage that includes the British newspaper The Guardian.

Schwab, a glazier who installs glass in San Francisco high rises, disputes the reckless driving allegation in a declaration filed last week in Solano County Superior Court and said the long delays in his case have made it more difficult for him to defend the reckless driving and DUI allegations.

Work crews change and he has no way of locating people he was with 16 months ago, said Schwab, who added if the charges had been filed sooner he could have tracked down co-workers.

“They would have been able to testify that I was not acting as if I was under the influence of caffeine – or any substance,” Schwab wrote.

He added, “I don’t recall what, if any, substances that may have contained caffeine I may have consumed that day.”

The District Attorney’s Office in its response Friday said it has not been shown that the prosecution intentionally delayed the case to produce a tactical advantage. Schwab’s declaration states that because of his work he is placed on jobs for short periods with different crews, the District Attorney’s Office filing adds.

“There is no indication that he would have had the names or contact information of these individuals, even had the charges against him been filed earlier,” according to the filing.

Michelle Ott, the ABC agent who arrested Schwab, was honored in June 2015 by Mothers Against Drunk Driving “for her efforts to save lives by enforcing alcoholic beverage and driving under the influence laws,” a release from the Department of Alcoholic Beverage Control said last year.

She is assigned to the Bay Area field enforcement office and made 54 arrests in 2014 for crimes related to underage drinking and 36 other arrests, including for public drunkenness and sales to intoxicated patrons at and around businesses licensed by the ABC, according to the release.

Ott made seven DUI arrests on the highway in 2014, the release said.

Reach Ryan McCarthy at 427-6935 or [email protected].