Highway 101 Interchange and Approaching Roadway Study

Accessing Highway 101 in Marin is a major source of congestion on local roads, which reduces the connectivity of communities across Marin. Some of the interchanges  have had long-standing visions for improvements that have not yet been planned in detail.  The interchanges vary in age; many of them were built in the 1950s and 1960s and have not been altered in meaningful ways to meet current and future demands of vehicles, transit, bicyclists, and pedestrians.

The purpose of the study is to identify a program of near- and long-term projects for twelve selected interchanges that will improve the operation and safety of these interchanges for all users, allowing smoother travel to, from and across Highway 101 and local roads.

Twelve interchanges were selected for the study based on input from stakeholders, including jurisdictional partners and the public, during the development of the Transportation Sales Tax Expenditure Plan. Each represents significant access for adjacent communities along Highway 101.

Please visit the Highway 101 Interchange Study website for detailed reports on each interchange, including existing conditions, constraints and opportunities.

Twelve interchanges were selected for the study based on input from stakeholders, including jurisdictional partners and the public, during the development of the Transportation sales Tax Expenditure Plan. Each represents significant access for adjacent communities along Highway 101. View the project study webpage for an interactive map with details about each interchange and the Final Implementation Report.

•  Alexander Avenue / Vista Point
•  Donahue St / North Bridge Road / Bridgeway
•  East Blithedale Avenue / Tiburon Boulevard (Route 131)
•  Tamalpais Drive / Paradise Drive
•  Sir Francis Drake Boulevard / Fifer Avenue / Industrial Way
•  2nd Street / Hetherton Avenue
•  North San Pedro Road / Merrydale Road
•  Manuel T. Freitas Parkway / Civic Center Drive
•  Lucas Valley Road / Smith Ranch Road
•  Alameda Del Prado / Nave Drive
•  Ignacio Boulevard / Bel Marin Keys / Nave Drive
•  San Marin Drive / Atherton Avenue

The Highway 101 Interchange and Approaching Roadway Study is funded through Measure AA – the re-authorization of the 1/2-Cent Transportation Sales Tax, approved by voters in 2018. The Expenditure Plan allocates 3% of the revenue from the sales tax, estimated to generate $25 million over the 30-year period of the Measure. The funding will be used to create the initial studies of 12 interchanges and will leverage regional, state and federal funds for a program of improvements to local road interchanges on Highway 101 in Marin.

Bill Whitney, PE, Project Manager
415-226-0823

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