SamTrans Looks to Improve Travel in the Dumbarton Corridor

SamTrans Looks to Improve Travel in the Dumbarton Corridor


SamTrans released draft recommendations that would address traffic congestion and create new mobility alternatives along the Dumbarton Corridor between Alameda County and San Mateo and Santa Clara counties. The recommendations were presented during the SamTrans Board of Directors’ August meeting and are the result of the Dumbarton Transportation Corridor Study. 

The study evaluated a wide range of transportation alternatives, and recommends operations and infrastructure improvements that would be phased in over time on the highway bridge, its approaches and the Dumbarton Rail Bridge.

In the near term, the study recommends increasing the frequency of the existing Dumbarton Express service and adding two new routes.  Bridge approach improvements are also recommended to help speed up bus service. These changes could be complete by 2020, with a one-time cost of approximately $51 million and operational costs of $12 million. The improvements would accommodate 13,700 more transbay riders daily, a 34 percent increase over the current rate.

By 2025, the study recommends establishing rail shuttle service running on the Dumbarton Rail Bridge between Redwood City and Newark with the goal of extending to Union City by 2030. The initial connection would cost approximately $975 million in capital costs to bring the bridge up to required safety standards and provide for dual tracks, with another $295 million in estimated costs needed to extend to Union City. This would provide transportation to 15,600 transbay riders daily and would be the first transbay rail transit option since BART opened the Transbay Tube in 1974. The study’s recommendations also include the addition of one express lane in each direction on Highway 84, an express lane flyover connecting express buses to US 101 and a number of more capitally intensive approach improvements meant to further enhance Dumbarton Express bus services.

In the longer-term, the study calls for the rail service operating on the Dumbarton Rail Bridge to be interlined with Caltrain and includes better connections with ACE and Capitol Corridor by 2035. This would require approximately $327 million in additional funds.

Funding to complete the near-term and longer term improvements will need to be secured. Senate Bill 595, which would authorize the Metropolitan Transportation Commission to ask voters to approve a regional bridge toll increase, includes $130 million for initial investment in mobility improvements on the Dumbarton Corridor.  

Public meetings on the study will be held on August 15 in Union City and August 16 in East Palo Alto.

The study was a collaborative project that enlisted the San Mateo County Transportation Authority, Alameda County Transportation Commission, AC Transit, and Facebook as partners, as well as the cities in the corridor. The SamTrans Board of Directors will receive a final report including public feedback from the hearings for their consideration in October.


About SamTrans: SamTrans operates 77 routes throughout San Mateo County.  Funded in part by a half-cent sales tax, the San Mateo County Transit District also provides administrative support for Caltrain and the San Mateo County Transportation Authority. SamTrans has provided bus service to San Mateo County customers since 1976. 

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Media Contact: Dan Lieberman, 650-508-6385