Dear Tiburon Peninsula Neighbors,

You may be aware that Caltrans is quickly moving forward with plans to repave and improve Tiburon Boulevard (SR131). While we welcome state investments in our infrastructure, one element of the plan is not only unnecessary but poses serious safety and traffic risks to our community. That’s why we’re asking you to speak up by joining a simple letter-writing campaign to government officials.

Your letter will help raise concerns about the proposed unprotected—or minimally protected—bike lanes between Trestle Glen and Blackfield Drive.

Under the current design, children who now bike along Greenwood Beach Road would have the option to ride on Tiburon Boulevard instead. This shift is unnecessary—given the safer Greenwood route—and creates serious risks:

• Danger to students: Children biking west to Bel Aire or east to Del Mar would be exposed to fast-moving traffic on this steep section of Tiburon Boulevard, with only flexible posts—or no barrier at all—for protection.
• Bus access: The bike lane design interferes with bus stops used by our Yellow Bus program, forcing 40-foot buses to cross or stop in the bike lane—endangering students and cyclists—or abandon those stops altogether.
• Traffic congestion: The already busy Trestle Glen intersection will likely face more backups and delays due to new bike crossings linking with the outbound lane.
• No demand: A much safer route already exists along Greenwood Beach Road. Even experienced cyclists say they would avoid this section of Tiburon Boulevard—so why tempt kids to ride here?
• Emergency response: Removing hard shoulders could severely limit drivers’ ability to pull over and yield to emergency vehicles.

These are not hypothetical concerns—Marin Transit, the Tiburon Peninsula Traffic Alliance (which oversees the school bus program), Reed Union School District, and the City of Belvedere have all raised red flags about the design.

With design 95% complete, this may be our last opportunity to speak up.

Please join the letter-writing campaign by filling out the Take Action form and clicking Start Writing. One of three pre-written letters will be sent directly to key Caltrans, Marin County, and State officials, urging them to revise the design and remove the proposed bike lanes on Tiburon Boulevard between Trestle Glen and Blackfield Drive.

Let’s work together to ensure our transportation infrastructure stays safe for everyone—especially children.

Thank you for caring about our community.

Warmly,

Dana Linker-Steele, Annie Defesche, Sandy Donnell, Tom Cromwell