Caltrans is beginning a major rehabilitation of Tiburon Boulevard that will bring new pavement, bikeways, ADA upgrades and drainage fixes to the town's main corridor from Highway 101 to downtown.

The City of Belvedere said in a notice posted Aug. 18 that construction on the State Route 131 Capital Preventive Maintenance Project is scheduled to begin in August 2026. The Town of Tiburon posted a similar notice July 13 confirming an August start for Phase 1. Caltrans' own project page lists a target start of September 2026, though it also describes Phase 1 as going into construction "mid- to late-summer of 2026." The agency has not clarified whether work has already begun.

Most high-traffic-impact work will happen overnight, according to both municipal notices. Neither specifies exact hours for the main project.

What's in the project

The scope goes well beyond repaving. According to Caltrans District 4's project page, the western segment will add Class I, II and IV bikeways, pedestrian refuge islands, curb ramps and sidewalk modifications. The central segment adds Class II and IV bikeways and intersection modifications. The eastern segment near downtown includes intersection modifications.

During construction, a temporary two-way Class I bike path will run on the inbound side of SR-131 from Strawberry Drive to Blackfield Drive.

Caltrans public information officer Matt O'Donnell is the project contact. The agency said the project aims to restore drainage systems that reduce the potential for highway flooding, improve ride quality and bridge a gap in the transportation network while improving bicycle access along the corridor.

The project stretches from roughly 1,000 feet west of the US-101 interchange to the Tiburon Boulevard/Main Street intersection. Completion is scheduled for winter 2027.

A separate retaining wall project at Tiburon Boulevard and Stewart Drive, which began May 28, is expected to wrap by the end of August. That project uses one-way traffic control Monday through Friday from 8 p.m. to 7 a.m.

No project cost has been publicly disclosed. The environmental comment period closed in November 2023, the final environmental document was released in January 2024 and final design was completed earlier in 2026.

The Town of Tiburon directed residents to sign up for the Tiburon Talk e-newsletter for construction schedule updates. O'Donnell can be reached at [email protected] or (510) 852-5113.