County of Marin - News Releases - San Antonio Bridge

For Immediate Release
July 27, 2015

Bridge Near Marin-Sonoma Border to Be Replaced

San Antonio Bridge job coincides with Marin-Sonoma Narrows project

San Rafael, CA – To mark its centennial, a historic northern Marin County bridge is being retired for vehicular traffic and supplemented by a new wider bridge, thanks to an infusion of federal funds.

A "before" photo of the old bridge over San Antonio Creek between Novato and Petaluma.Approved as part of the Marin Sonoma Narrows High-Occupancy-Vehicle Widening project in October 2009, the San Antonio Road Bridge Replacement Project proposes to realign a portion of San Antonio Road between Novato and Petaluma, including construction of a new bridge over San Antonio Creek right next to the existing bridge, built in 1917 and considered historic. The old bridge will remain standing for bicycle and pedestrian use but will be closed to vehicular traffic.

A public workshop is scheduled for 5:30 p.m. September 9, at the Margaret Todd Senior Center in Novato to provide details about the project’s context, scope and design. The project is sponsored by the County of Marin’s Department of Public Works and managed by the Transportation Authority of Marin.

The construction area is close to Highway 101, north of Olompali State Historical Park and the Silveira Ranch and just south of the Marin-Sonoma county line. The project will realign San Antonio Road with a new bridge with standard lane and shoulder widths, wide enough to accommodate pedestrians and bicyclists. The old bridge will be maintained for use by bike riders and walkers.

Preliminary engineering and environmental evaluations started in late 2014 and should be completed by this fall. Final design starts this fall and continues into summer 2016. Construction is anticipated to start as early as spring 2017 and will take about a year and a half to complete.

The project is expected to cost $5.5 million, and funding will come from the federal government’s Local Highway Bridge Program. The national program distributes about $300 million annually to replace or rehabilitate public highway bridges over waterways, other topographical barriers, other highways, or railroads when the state and the federal highway administrations determine that a bridge is significantly important but is unsafe because of structural deficiencies, physical deterioration or functional obsolescence.

The Margaret Todd Senior Center is at 1560 Hill Road in Novato.

If you are a person with a disability and require information or materials in alternative formats -- or if you require accommodation to participate in a county program, service or activity -- please contact department staff at (415) 473-7331 or (415) 473-4381 (voice/TTY) or e-mail


Ernest Klock
Assistant Director
Public Works

3501 Civic Center Drive.
San Rafael, CA 94903
(415) 473-6552
Email: Ernest Klock
Public Works website