Highway 101 widening begins in Petaluma

Wielding ornamental gold-colored shovels, Sonoma County transportation officials Wednesday broke ground on a 3.3-mile Highway 101 widening project through the heart of Petaluma.

The ceremony marked the symbolic beginning of the end for the largest transportation project north of the Golden Gate Bridge, a two-decade-long effort to add carpool lanes and decrease congestion along Sonoma County’s main artery.

Since 2001, work has progressed in stages as funding for the $1.2 billion project came in fits and starts, leaving just the Petaluma segment as the last gap from Windsor to the Marin County line.

“Here we are, two decades later on the last segment,” said Supervisor David Rabbitt. “Not only are we going to add capacity, not only are we going to increase safety, we’re going to improve people’s lives.”

Officials warned of traffic as construction takes place over the next three years from Corona Road to Lakeville Highway, a stretch that sees 150,000 vehicle trips per day. But they said that the commute through southern Sonoma County will be much easier once the work is finished at the end of 2022.

“The widening of Highway 101 is going to be welcome by everyone in our community,” said Mark Landman, chair of the Sonoma County Transportation Authority. “Everyone here can stop and appreciate what our actions are bringing to the people of Sonoma County. While it’s been a long and hard journey to get here, the end is clearly in sight.”

Caltrans contractor Ghilotti Construction Company of Santa Rosa is building the $121 million project that includes $85 million from the state gas tax increase, $28 million from Sonoma County’s Measure M sales tax, and $7 million from Petaluma.

The first order of business is constructing sound walls to shield residential properties that front the freeway, according to Kathy Miller, a Petaluma city councilwoman and SCTA board member.

Officials fast-tracked the sound wall portion of the project after a 2016 fire along Highway 101 in Petaluma destroyed a strand of eucalyptus trees that had offered some privacy for homes on Stuart Street.

“One of the things that was important to me was that the first phase included putting the sound walls up so folks have protection from freeway noise,” Miller said. “That’s a huge win for the community.”

Three sound wall segments will be built along the northbound lanes — from Caulfield Lane to East Washington Street, along the Vintage Chateau Apartments, and in front of two mobile home parks at Corona Road — and one sound wall will be built on the southbound side along the Payran neighborhood at East Washington Street.

While the sound wall work progresses, crews will use packed dirt to construct an incline that will eventually lead to a new highway bridge over the SMART tracks and over the location of the future Rainier Avenue extension. Wednesday’s groundbreaking was held where Rainier currently dead-ends at Highway 101, the spot where Caltrans will build a new underpass using Petaluma’s $7 million contribution.

“The city of Petaluma is very, very, very excited to see this getting started,” said Kevin McDonnell, a Petaluma city councilman. “It’s not great being last, but it’s great at last to be getting started.”

James Cameron, SCTA director of projects and programming, said work over the SMART tracks will take place at night in order to not disrupt the train schedule. The contractor is still coordinating with SMART about potential closures of a bike path that the rail agency is constructing along the tracks.

Actual highway lane widening will begin in the median, which will take most of 2020, Cameron said. The second year will be spent widening the outside of the northbound lane, and work will shift to the southbound side in 2022.

This staged construction, which has been employed on other segments of Highway 101 in Sonoma County, helps keep cars moving while crews work.

“You have to maintain traffic while building it,” Cameron said. “That’s why it takes three years.”

Temporary concrete barriers called K-rail will be installed in the work zone, reducing traffic speeds. Two-lanes of traffic in each direction will continue flowing for the most part, except for occasional late night closures of one lane, Cameron said.

The East Washington Street interchange, which completed major improvements in 2013, will get a slight modification in the current project. The northbound offramp will terminate farther west, giving more space for cars turning east onto East Washington Street and improving the intersection with McDowell Boulevard.

Also included in the project are ramp meters, electronic signs and traffic-monitoring equipment.

The groundbreaking comes as another Highway 101 widening project wraps up at Kastania Road just south of Petaluma. That project should be completed by the end of the year, officials said, opening up about seven miles of carpool lanes from Lakeville Highway to the county line.

Another widening project from the county line south to Novato is being designed but won’t break ground for at least a year, officials said. It is funded through a bridge toll measure, which is being challenged in court.

California Transportation Commissioner Jim Ghielmetti, who lives in San Francisco and has ties to Sonoma County, said he anticipates the Highway 101 project’s ultimate completion.

“I look forward to getting this road open soon,” he said. “I’m building a house in Healdsburg.”

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