A wine tour van driver failed as a designated driver after he was arrested on suspicion of driving drunk while shepherding out‑of‑state visitors to Healdsburg-area wineries, the CHP said Monday.

Eugene Cremen, 60, of Napa, was driving eight Minnesota and Ohio visitors to area wineries Friday in a van registered to Napa Valley Wine Country Tours out of American Canyon, CHP Officer Kimberly Lemons said. After wrapping up stops in Dry Creek Valley about 5:30 p.m., passengers headed to the van, where they found Cremen passed out, she said.

“They noticed he was slumped over the wheel and they had a hard time waking him,” Lemons said.

After passengers awakened him, they went on their way. But within minutes, passengers started calling 911, telling dispatchers their driver was weaving in and out of his lane on south Highway 101 and nearly hit a big rig, CHP said.

Cremen eventually stopped along the Old Redwood Highway offramp near Healdsburg, where officers found the van, CHP said.

A preliminary test showed Cremen, who had a prior DUI arrest in the last decade, with a blood‑alcohol level three times the legal 0.08‑percent limit, and nearly six times the 0.04-percent limit for commercial drivers, Lemons said.

There were no alcohol containers in the vehicle, but officers suspect he kept the drink in a Thermos, Lemons said.

A Napa Valley Wine Country Tours employee said Monday afternoon no one at the company was available for comment.

Passengers were picked up by a ride-sharing service after the driver was arrested. Lemons praised them for trying to stop the driver and calling for help. They likely prevented a crash, she said.

You can reach Staff Writer Randi Rossmann at 707‑521-5412 or randi.rossmann@pressdemocrat.com. On Twitter@rossmannreport.