Caltrans District 4 Marin County Newsletter

Marin Sonoma Narrows Ribbon Cutting Celebrates Culmination of 16-year Project in Marin, Sonoma counties

Caltrans and its local partners celebrated the Marin-Sonoma Narrows (MSN) HOV lanes conclusion with a ribbon cutting event at Olompali State Historic Park in Novato on Friday, Oct. 3. The three-lane configuration was completed on the morning of Monday, Sept. 29.

About 100-plus people attended the ceremony, and 10 speakers gave their perspective on the project, including U.S. Congressman Jared Huffman, California Senator and Senate President Pro Tempore Mike McGuire and Acting Caltrans District 4 District Director David Ambuehl.

While the Narrows’ stretch is 16 miles, the completion of the third lanes connects 52 miles of continuous HOV lanes that stretches from the Richardson Bay Bridge in Marin County to Windsor in Sonoma County.

The B7 portion includes widening US-101 to install HOV lanes for 3.5 miles along the northbound lanes from North Novato to the Marin, Sonoma line, and for 6.3 miles along the southbound lanes from De Long Avenue to the county line.

For more and to see a YouTube video and a photo gallery, go to The Marin-Sonoma Narrows Project | Caltrans

Manuel T. Freitas Roundabout Project in San Rafael Continues to Progress into Fall 2025

Several stages of the Manuel T. Freitas Roundabout Project in San Rafael were finished in the summer and fall of this year.

In September, Caltrans closed the Southbound US-101 on-ramp from Eastbound Manuel T. Freitas Parkway for a 55-hour closure as crews tore up and then reconstructed the existing roadway and re-paved the area. Temporary pedestrian access and a traffic detour were implemented during construction.

For the overall project, Caltrans is working to relocate the bus stop at the northbound Freitas Parkway off-ramp to make it safer and Americans with Disabilities Act (ADA) accessible.

Caltrans is proposing to improve the intersection of Freitas Parkway, Civic Center Drive, and Old Redwood Highway by installing a roundabout. This change will improve traffic flow and make this busy intersection/off-ramp safer for vehicles and pedestrians.

The project went into winter suspension in October. It is scheduled to start up again in the spring of 2026.

For more info, see Roundabout project at Manuel T. Freitas Parkway/US-101 interchange | Caltrans

State Route 131 (Tiburon Boulevard) Capital Preventive Maintenance Project Progressing with Phased Approach

After engaging with stakeholders throughout the spring and summer, Caltrans is inching toward 100 percent design for the State Route 131 (Tiburon Boulevard) Capital Preventive Maintenance project.

Caltrans has been engaged in ongoing discussions with the Town of Tiburon and other stakeholders regarding options for Phases 1 and 2.

Phase 1 construction is scheduled to begin in summer 2026.

Caltrans proposes to repair approximately 4.6 miles of East Blithedale Avenue/Tiburon Boulevard from approximately 1,000 feet west of the U.S.-101 interchange extending east to the Tiburon Boulevard/Main Street intersection during Phase 1.

The integration of Complete Streets elements also remains a key priority for Caltrans, especially as the agency works to meet critical deadlines to move the project forward.

Phase 1 includes bikeways along SR-131 from Tower Drive, near the US-101 interchange, to Blackfield Drive, and introduces a temporary two-way Class I bike path on the inbound side of SR-131, extending from Strawberry Drive to Blackfield Drive.

Phase 2 will implement the permanent configuration of the Class I path, which includes reconstruction of the landscaped median. It also will include bikeways from Blackfield Drive to Trestle Glen Boulevard, along with bus stop improvements. Phase 2 will involve heavy engagement from stakeholders before moving forward.

For more information, see SR 131 Capital Preventive Maintenance | Caltrans.

Capital Preventive Maintenance Project along State Route 37 (SR-37) Making Progress in Fall

Caltrans continued its Capital Preventive Maintenance Project along Eastbound and Westbound State Route 37 (SR-37) in September and October in the Novato area of Marin County.

Crews replaced the concrete median barrier with a current standard, and most of the soil stabilization has been completed.

Crews also built a new concrete deck on the shoulder of Eastbound SR-37 at Simmons Slough (a wetland area that is a tributary to Novato Creek) with bicycle-compliant guardrail for incorporating that aspect of multimodal traffic.

Caltrans is targeting late October for the start of paving work in both directions of Eastbound and Westbound SR-37. Ongoing work is guardrail replacement at most interchanges within the construction area in between Atherton Avenue and the Petaluma River Bridge in Novato for guard rail work. The project’s target timeline is December 2025.

For more on other SR-37 projects, check out Ramp, Lane Closures for Westbound, Eastbound SR-37 Capital Preventive Maintenance Project in Marin County | Caltrans.

Setting the PACE: Public Affairs Customer Engagement Site is Now Live!

District 4 is proud to announce the launch of our new Customer Service Request (CSR) platform. PACE, the Public Affairs Customer Engagement site, provides a regularly updated breakdown of services requested and rendered across the district.

• The CSR dashboard aims to provide an overview of the responsiveness to maintenance services requested across the nine Bay Area counties.
• The data represented as month-to-date falls within a rolling 30-day Service Level Agreement (SLA) and is updated weekly.
• We strive to close 60% (or more) of all monthly service requests received via the CSR website portal.
• For more information or to leave comments/suggestions, please contact D4CSLTEAM@dot.ca.gov.
• To report a highway issue/problem, please submit a CSR ticket through the Customer Service Request Form.

The Marin County newsletter will be distributed on a regular schedule.

For 24/7 traffic updates, please visit 511.org: https://x.com/511SFBay
For real-time information, visit Caltrans QuickMap: https://quickmap.dot.ca.gov
Follow us on X: https://x.com/CaltransD4
Or call 1-800-472-7623, 1-800-427-ROAD for state highway conditions statewide.

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