Third lane opens for Hwy. 101 motorists outside of Petaluma

The commute through southern Sonoma County was a little bit smoother Monday.

A lofty vision to create a continuous carpool lane on Highway 101 through most of Sonoma County crept 4four miles closer to reality as transportation officials opened the first new section of lanes since 2013.

The expanded highway represents the completion of several projects at the Sonoma-Marin county line designed to reduce congestion and improve safety along Highway 101. It leaves one final piece of the so-called Sonoma-Marin Narrows project - from the county line to Novato - unfunded.

Starting Monday morning, commuters were able to use a third freeway lane in each direction from Lakeville Highway in Petaluma to the county line. The Petaluma River bridge carpool lanes, which had been off limits since the bridge was expanded in 2016, were open in both directions for the first time along with new lanes on the San Antonio Creek bridge that were completed in August.

A separate construction contract between the two bridges was deemed far enough along for officials to open the carpool lanes through the key bottleneck, although work around the Kastania Road interchange and a final round of paving is expected to continue into next year.

At a ceremony last week to celebrate the milestone achievement, transportation officials touted the safety features of the newly widened freeway. The ribbon-cutting event was held at the southern terminus of Petaluma Boulevard South, a new frontage road created from the northbound lanes of the old highway.

Sonoma County Supervisor David Rabbitt noted that the nearby driveway for the Corda Dairy was one of several unsafe direct highway access points that now use new frontage roads on both sides of the freeway.

“That driveway there hit the freeway not too long ago,” Rabbitt said. “I’m very pleased with the safety aspect of this project. It’s not just about expanding capacity.”

The projects from the Petaluma River to the county line represent about $280 million worth of work out of the $1.2 billion effort to remake Highway 101 in the North Bay by adding a continuous carpool lane in both directions from Novato to Windsor.

Mark Landman, chairman of the Sonoma County Transportation Authority, said that local officials have been adept at cobbling together regional, state and federal funding for the various projects by using matching funds from the Measure M sales tax.

Each dollar of the quarter-cent sales tax that voters passed in 2004 has been leveraged to attract $5 in outside funding for the highway project, Landman said. The SCTA is considering extending the countywide sales tax on the November ballot.

“Measure M has been the seed money,” Landman said. “With the passage of that measure, we became a self-help county. Those were the magic words that changed everything.”

Besides safety and congestion relief, officials said the project is also designed to reduce greenhouse gas emissions. The new lanes, open to vehicles with two or more occupants during commute hours, encourage people to carpool and take vehicles off the road, Petaluma City Councilman Kevin McDonnell said.

The project also includes a new bike lane along the freeway frontage from Petaluma to Novato.

“As one of the two most impacted cities, the people of Petaluma thank all of the partners for this project,” McDonnell said. “We declared a climate emergency and we are big advocates for the bike lane.”

The carpool lane project began in Santa Rosa in 2001 and expanded north to Windsor and south to Petaluma. Before this week, the newest segment of carpool lanes in Sonoma County was a nearly 2-mile stretch from the north end of Petaluma to Pepper Road opened in 2013.

The final piece of planned highway widening in Sonoma County, a 3.3-mile segment through the heart of Petaluma, broke ground in October. The $121 million project is on track to finish at the end of 2022.

Marin County transportation officials are now focused on funding the stretch between the county line and Novato, the last bottleneck along the corridor.

Anne Richman, executive director of the Transportation Authority of Marin, said she is hopeful the California Transportation Commission next year approves a request for $40 million in state gas tax money, which would fully fund the project.

If it is funded next year, work could start in early 2021 and open at the end of 2023, she said.

Novato City Councilman Eric Lucan said that, once all of the work is wrapped up, the section of highway once known as “The Narrows” will no longer have its defining characteristic.

“When this is all done, what will we call it?” he said. “It won’t be the Marin-Sonoma Narrows anymore because it will be expanded. We’ll have to rebrand it.”