The flaggers and cones that started appearing along Tiburon Boulevard this fall belong to a Caltrans project whose main event is still months off. The new pavement everyone is waiting for is scheduled for spring 2027. The crews out there on weekdays now are rebuilding curb ramps and sidewalks. The other way into San Francisco is running on an interim plan too. Golden Gate Ferry has put Tiburon on a temporary weekday schedule because of mechanical issues, and several of the trips listed as "ferry" departures are now buses that leave from Tiburon & Main. That's the same intersection where the Caltrans work zone ends.
Both ways off the peninsula are running on interim arrangements this fall. It helps to know which stage each one is in.
What the crews are building right now
The project's formal name is the State Route 131 Capital Preventive Maintenance Project. Highway 131 is Tiburon Boulevard. Caltrans' project page says Phase 1 starts about 1,000 feet west of the US-101 interchange and ends at the Tiburon Boulevard and Main Street intersection. The Ark reported in August that the whole project covers 4.6 miles. It starts where East Blithedale Avenue meets Tower Drive and ends at the downtown roundabout, where Tiburon Boulevard turns into Paradise Drive.
The current stage started with a Caltrans traffic advisory dated September 16. It said curb ramp and sidewalk work could begin as early as Monday, September 21. Crews would start near the US-101/SR-131 interchange and work east toward the Tiburon waterfront. The advisory spells out the terms:
"Intermittent one-way traffic control may be required between 7 a.m. and 5 p.m. Monday through Friday. Paving for the project is scheduled for spring 2027."
Phase 1 includes 28 curb ramps. Flaggers may direct drivers, pedestrians may face detours during some stages, and Caltrans says some bus stops may be affected. All the work depends on the weather.
These hours are different from what the Town of Tiburon expected in summer. A Town notice posted July 13 said most of the high-traffic-impact work on the boulevard would happen overnight. The curb ramp and sidewalk stage Caltrans announced for fall runs in daylight on weekdays. So for now, the time of day to plan around is the middle of the workday. Late-night trips aren't the issue at this stage.
The order of operations, from now into 2027
The fall work is the first of several stages. Caltrans spokesperson Matt O'Donnell told The Ark that the agency plans to pause during the winter months and expects construction to run until July 2027. Caltrans' own project page gives the completion date as "the winter of 2027." Put together, the published schedule looks like this:
- Late summer setup. An August 24 advisory said curb ramp and sidewalk work could start Monday, August 31, from 7 a.m. to 5 p.m. on weekdays.
- Fall curb ramps, moving east. The September 16 advisory set a possible September 21 start near Highway 101, with crews working toward downtown.
- Winter pause. Work stops for the winter months, according to what O'Donnell told The Ark.
- Spring 2027 paving. This is the stage that changes how the road feels to drive.
- Completion. Caltrans says winter 2027. The Ark reported July 2027 for the end of construction.
Paving is only one part of the project. Caltrans says the work is meant to improve ride quality, restore the existing drainage systems and fill a gap in the bicycle network. The project is split into three segments. The western segment gets Class I, II and IV bikeways, intersection changes, curb ramps, pedestrian refuge islands and sidewalk work. The central segment gets Class II and IV bikeways and intersection changes. The eastern segment, closest to downtown, gets intersection changes only.
Why the bike changes stop at Blackfield Drive
The eastern segment's shorter list is the part cyclists will notice most. In Phase 1, the new bikeways run along Tiburon Boulevard from Tower Drive near Highway 101 to Blackfield Drive. Phase 1 also adds a temporary two-way Class I bike path on the inbound side of the boulevard, from Strawberry Drive to Blackfield Drive.
Past Blackfield, Phase 1 doesn't add bike lanes. The Ark reported in November 2025 that bike lanes inside town limits, from Blackfield Drive to Trestle Glen Boulevard, had been moved to a second phase. At that time the paper said funding was to be secured in 2026 and construction was targeted for early 2029. The same report said the delay followed concerns about school buses, including a claimed conflict at the Jefferson Drive stop. It also noted that bike advocates disputed some of the other stop impacts that had been raised. That timeline was the plan as of late 2025. The Caltrans project page doesn't give a date for Phase 2.
So for the next few years, the bike network will be noticeably better west of Blackfield and mostly unchanged east of it. Phase 1 paves the road all the way to Main Street, but its bike improvements stop at Blackfield.
The ferry fallback starts where the work zone ends
The Golden Gate Ferry skips the boulevard for most of the trip, but it is on an interim schedule of its own right now. The Tiburon–San Francisco route page says that "due to mechanical issues, the following temporary weekday Tiburon schedules are in place until further notice."
As of late October, the page lists only two actual boats among weekday Tiburon-to-San Francisco departures. One is the 6:50 a.m. ferry. The other is a 1:15 p.m. ferry that goes by way of Sausalito and arrives at 2:05 p.m. The 8:10 a.m., 9:55 a.m., 11:50 a.m. and 4:30 p.m. departures are buses. Going the other way, the 7:30 a.m. San Francisco departure is listed as canceled. The 12:10 p.m. and 7:15 p.m. trips are ferries, and the rest of the listed returns are buses.
Golden Gate's October 19 service bulletin covered October 19 through 23. It put the Tiburon bus pickup at Tiburon & Main and the San Francisco pickup at Embarcadero and Washington Street. Some times in that bulletin are different from the live route page. The bulletin lists a 9:35 a.m. bus from Tiburon, for example, while the route page shows 9:55 a.m. The route page is the one to check on the morning you travel. This isn't the first time this year either. A Golden Gate alert from August 5 reported Tiburon trip disruptions from August 5 through 7, also because of a mechanical issue.
Here's what the bus trips mean in practice, based on the route page:
- Time. Golden Gate says bus trips can take up to 55 minutes.
- Bikes. Each bus carries up to three bikes.
- Fares. Riders need to tag on and off with Clipper or contactless payment on Golden Gate buses.
The two situations meet at that pickup point. Tiburon & Main is the eastern end of Caltrans' Phase 1. Weekday bus trips that replace ferries start at the same intersection where the curb ramp crews are headed. This fall, someone who switches from driving to the ferry may still end up starting at Tiburon & Main on a bus.
Planning around both through the holidays
The curb ramp work is weekdays only, and so is the temporary ferry schedule. Weekends on the boulevard fall outside both. One town event in early November falls on that side of the calendar. The Town's Diversity Inclusion Task Force is hosting a free Diwali by the Bay celebration at Zelinsky Park, 1505 Tiburon Boulevard, on Saturday, November 7, from 1 to 4 p.m., according to the Town of Tiburon's notice.
Caltrans has said it will post details about more intersections in future traffic advisories on the SR 131 project page. The Town sends construction schedule updates through its Tiburon Talk e-newsletter. For a weekday trip to the city, the most useful thing to check before leaving is whether your departure is listed as a ferry or a bus on Golden Gate's Tiburon route page.
Carla follows changes like this because they shape everyday life on the peninsula, from how long the morning commute takes to which spring weeks a freshly repaved Tiburon Boulevard will finally be smooth. If you're wondering what this construction timeline could mean for your own plans over the coming year, Carla Giustino is glad to talk it through. Request a complimentary Marin market consultation.
