Highway widening set to start in Petaluma

Construction work along Highway 101 in Petaluma is poised to ramp up this summer as officials finalize a contract for the three year project that will widen the freeway from Corona Road to Lakeville Highway.

Ghilotti Construction Company of Santa Rosa was the lowest bidder in the process that ended last week, coming in $1million less than the estimated $80 million project, according to Caltrans. The contract is scheduled to be approved in July, and work will begin in mid-August, according to James Cameron, director of projects and programming at the Sonoma County Transportation Authority.

The project will open up new carpool lanes through Petaluma to the Sonoma-Marin county line, and it will complete a 20-year Highway 101 widening project through most of Sonoma County.

“It will be a pain during construction, but it will be well worth it in the long run,” said Supervisor David Rabbitt, an SCTA board member. “To have new infrastructure, it’s going to be a good thing. I’m glad we can finally put that project to rest.”

Meanwhile, work continues on two highway projects near the county line that should wrap up by the end of the year, Cameron said.

Workers on a project at the San Antonio Creek bridge are set to shift traffic one last time to the final configuration on June 21, Cameron said. That will facilitate lane striping and median barrier work. That project, including a bike path under the bridge, should be complete by August, he said.

A few miles north at the Kastania Road overpass, widening work on the southbound lanes should last until December, Cameron said. At that point, more than 4 miles of new carpool lanes will be open from the Petaluma River to the county line.

“There are a couple of more traffic shifts, but it should be open by the end of the year,” Cameron said.

Dirt from the work at the county line has been transplanted to the next project in Petaluma, and motorists have observed piles alongside the highway around the Petaluma outlet mall. That will eventually form a new embankment to take the freeway over the railroad tracks and an underpass for an extension of Rainier Avenue.

Cameron said the first year of work won’t be as visible as it will take place under the embankment and, simultaneously, around East Washington Street to build new sound walls. By this time next year, the lane widening should be underway, which will involve three traffic shifts of about a year each. First, the median will be widened, then the northbound lanes, followed but the southbound lanes.

Barring delays, the project should finish by the end of 2022. At that point, the last piece of the so-called Sonoma-Marin Narrows should be under construction from the county line to Novato. Marin County has been approved to use bridge tolls to fund that project, which is still in the design phase.

Rabbitt said he was glad that the Petaluma highway project came in under budget. Sonoma County struggled for years to fund the final segment of work, finally receiving $85 million in March from the new state gas tax.

“I’m glad the contract came in,” Rabbitt said. “We didn’t have to get extra dollars. That would have been tough.”

(Contact Matt Brown at matt.brown@arguscourier.com.)