Marin County has received $1.2 million in state funding to relieve a persistent bottleneck at a San Rafael offramp.

The California Transportation Commission announced the award this week as part of nearly $4 billion in allocations across the state. The funds headed to Marin come from Senate Bill 1 gas tax revenues.

“This was the last piece of the funding,” said Anne Richman, executive director of the Transportation Authority of Marin, the planning agency that is leading the $9.2 million project. Funding also includes local tax revenue from Measure A and Measure AA.

“The project has been in development for some time and is a priority for the city of San Rafael, the county and TAM,” Richman said. “We’re pleased to see it will all come together.”

The project area is at the intersection of Highway 101 and Interstate 580, where local drivers converge with commuters headed to the Richmond-San Rafael Bridge. The project will widen the northbound Highway 101 offramp to Bellam Boulevard from one lane to two lanes. This will separate traffic turning left onto Bellam Boulevard from drivers turning right or heading straight onto eastbound Interstate 580. The Interstate 580 onramp across the street also will be widened.

The project includes a new concrete barrier, traffic signal changes, storm drain improvements, new pavement markings and a retaining wall.

“It also realigns the crosswalk to make it safer for pedestrians,” Richman said.

Although it is a Transportation Authority of Marin project, the Marin County Department of Public Works is taking the lead on construction under a partnership agreement.

County staffers were expected to open construction bids this week. Staff plan to make a recommendation for a contract at a Board of Supervisors meeting next month or early December, said Chris Blunk, assistant director of public works.

“The project will help greatly reduce the afternoon backup on northbound 101 and eastbound I-580 waiting to exit to Bellam,” Blunk said. “Traffic studies show there should be an immediate reduction in stopped traffic on the freeways.”

Julian Kaelon, spokesperson for the county public works department, said preparation work is expected to begin in January with construction fully underway in the spring. The project is expected to wrap up in the fall.

San Rafael city officials have been supportive of the project.

“The city is grateful to the county of Marin for being the lead agency on this important project,” San Rafael Mayor Kate Colin said. “It will improve traffic congestion, as well as enhance pedestrian mobility and safety for years to come.”

The offramp project is separate from the larger effort called the “US 101/I-580 Multimodal and Local Access Improvement Project,” which involves work in the same area.

Transportation Authority of Marin officials kicked off the environmental review for that project earlier this month.

Planners are looking at options with cost estimates as low as $20 million and up to nearly $290 million. That project looks at potential connectivity improvements between northbound Highway 101 and eastbound Interstate 580. A large focus is on traffic improvements such as potential roundabouts as well as bicycle and pedestrian improvements up and down the Bellam Boulevard corridor.

Omar Carrera, chief executive officer of Canal Alliance, said he appreciates the time and investment in the planning for the corridor.

“We believe that these improvements will enhance the quality of life for Canal residents and contribute to a more vibrant and sustainable community,” Carrera said.