Caltrans commits to next phase of Tiburon Boulevard upgrades

Caltrans will move ahead with a second phase of upgrading Tiburon Boulevard.

The transit agency will repave the Tiburon Peninsula’s main thoroughfare next year and add pedestrian improvements and bike lanes — except for excluding the lanes on a mile-long stretch between Trestle Glen Boulevard and Blackfield Drive.

The decision by Caltrans over the summer to exclude bike lanes from that stretch was controversial, pitting cycling advocates against local officials who oversaw school bus service and public transit. Other bike lane opponents included residents who feared they would add to traffic congestion.

At the time, Caltrans said it would split the project into two phases and pledged the second phase would begin with public forums and convening a task force where improvements, such as paved islands for school bus stops and additional upgrades to bike lanes, could be discussed.

“Caltrans is committed to funding and delivering the phase two portion of the State Route 131 Capital Preventive Maintenance project,” Caltrans spokesperson Matt O’Donnell said Friday.

“In partnership with Marin County and the town of Tiburon, Caltrans will assist and provide technical support to form a stakeholder task force to provide inclusive community input and develop an endorsed scope and configuration for bikeway and transit improvements,” he said. “With the task force’s endorsement, Caltrans plans to secure funds in 2026, complete design, permitting and right of way for construction by early 2029.”

Caltrans’ commitment to a second phase starting with a public engagement process drew praise.

“I’m excited that Caltrans will be reaching out to the community and include the community’s vision in the final proposal,” Tiburon Mayor Holli Thier said.

“We at MCBC look forward to participating in the upcoming work with Caltrans and members of the community to assure that Tiburon Boulevard becomes a road that serves all current and potential users of the corridor, and provides safe and accessible facilities for bicyclists, pedestrians, and transit riders,” said Warren Wells, policy and planning director for the Marin County Bicycle Coalition.

“This means, at a minimum, building protected bike lanes, closing dangerous high-speed slip lanes, adding median refuges, and ensuring ADA access to all bus stops,” he said.

“The improvements to pedestrian and bicycle access that are included in phase one are an inordinate improvement from the current condition and reflect the community’s desires,” said Matthew Hartzell, planning director for WTB-TAM, a cycling advocacy group. “Unfortunately, that which could have been done in phase one must now be postponed to phase two, which is an imposition on Tiburon, the county and the community.”

Hartzell said he hoped the public engagement process would lead to solutions “with regards to interactions between bicyclists and school buses at bus stops” and challenges for cyclists at key intersections.

“WTB-TAM has put forth design solutions to all of the above concerns and looks forward to having a dialogue with the community, government agencies and the state,” he said.

The engagement process is expected to begin in the new year, county officials said. Among the issues to be discussed are possibly widening sections of Tiburon Boulevard to accommodate improvements, which would entail obtaining right of ways from utilities and property owners.