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The Transportation Authority of Marin (TAM) has begun the planning and environmental phase of a proposed project to construct a direct highway connection from northbound US-101 to eastbound I-580 in Marin County. TAM will complete the environmental analysis to evaluate options and work with the community and stakeholders to select a preferred alternative. 

This project is a collaborative effort between TAM, the California Department of Transportation (Caltrans), and the cities of San Rafael and Larkspur.   

Currently, drivers who wish to access the Richmond-San Rafael Bridge (I-580) via northbound US-101 have to exit the freeway and travel on East Sir Francis Drake Boulevard or across Bellam Boulevard to the bridge entrance.  Having to drive on local streets causes congestion and traffic delays on northbound US 101 and on local streets, including Sir Francis Drake Boulevard and Bellam Boulevard. 

The proposed project will allow vehicles to continue along US-101 northbound onto a new highway connector in San Rafael and merge directly onto I-580 eastbound toward the Richmond-San Rafael Bridge. 


The objective of the proposed project is to reduce congestion and improve traffic flow on NB US-101 and local streets. TAM will accomplish this by providing a direct highway connection from northbound US-101 to eastbound I-580 and the Richmond-San Rafael Bridge. The project will also enhance existing multi-modal (bicycles pedestrian, and transit) connections.   

Bicycle and pedestrian connections will also be improved along Bellam Boulevard.  Additional benefits associated with this project include more efficient regional and local bus routes in the project vicinity and other project amenities, such as landscaping and streetscape beautification.  


TAM is working to reduce bottlenecks and back-ups on eastbound I-580 as it approaches the Richmond-San Rafael Bridge. In collaboration with the Metropolitan Transportation Commission (MTC), Caltrans and Contra Costa Transportation Authority, a third lane has been opened on the bridge to help alleviate heavy trafficThe third lane now extends from the existing I-580 onramp from East Sir Francis Drake Boulevard on to the bridge.   

As part of the new US-101 to I-580 connector project, a new auxiliary (extra) lane will be built along eastbound I-580 from the new entry point to the existing onramp from east Sir Francis Drake Boulevard. This will allow drivers to use three lanes from the new connector all the way onto the bridge and into Richmond


This project received voter support for funding in the local Marin Transportation Sales Tax Measure AA, approved in November 2018. TAM also advocated for this project to be included in Regional Measure 3which was approved in June 2018. 

Looking North
Looking Northeast

TAM is in the process of convening stakeholder working group to help guide the Northbound US-101 to Eastbound I-580 Direct Connector project. Check back here for meeting schedules, agendas, presentations, minutes, and other pertinent information. 

Connie Fremier, P.E.