Bay Crossings Studies | Plans + Projects | Our Work

Bay Crossings Studies

By bridge, BART or ferry, travel across San Francisco Bay unites our region.

MTC periodically takes a big-picture view of the ways residents cross the bay. We look at existing options, and compare them against future travel forecasts.

Developed as part of MTC's Horizon initiative, a 2019 Perspective Paper, Crossings: Transformative Investments for an Uncertain Future examined seven different options for a new way to cross the bay:

  • A rebuilt San Mateo-Hayward Bridge
  • A new Mid-Bay Bridge for cars, trucks and buses connecting Interstate 380 in San Bruno to Interstates 880 and 238 in San Lorenzo
  • A new BART tunnel connecting new stations in Oakland's Jack London Square and Alameda with stations at Mission and Main streets and Mission and Second streets in San Francisco, providing redundancy to the Embarcadero and Montgomery stations in San Francisco's Financial District
  • A new BART tunnel serving Jack London Square and Alameda in the East Bay, and Mission Bay, South Beach and Third and Mission streets in San Francisco
  • A conventional rail tunnel connecting Caltrain and Capitol Corridor services through the Salesforce Transit Center
  • Paired BART and auto tunnels connecting downtown Oakland and Jack London Square to San Francisco's India Basin, Mission Bay and South of Market neighborhoods
  • Paired BART and conventional rail tunnels connecting Oakland and Alameda with San Francisco


The Crossings effort was led by MTC and BATA with the support of partner agencies, including:

  • Alameda County Transportation Commission
  • BART
  • California State Transportation Agency
  • Caltrain
  • Caltrans
  • Capitol Corridor
  • City of Oakland
  • City and County of San Francisco
  • San Francisco County Transportation Authority
  • San Francisco Municipal Transportation Agency

MTC's  2012 Bay Crossings Study Update included data from AC Transit, Altamont Commuter Express, BART, Caltrans and the San Francisco Bay Area Water Emergency Transportation Authority. Among the study's recommendations:

  • Additional boarding platforms at BART’s Embarcadero and Montgomery stations
  • Speeding BART service in San Francisco and the East Bay by allowing trains to skip stops at some stations
  • East Bay bus terminal with frequent shuttle service to/from San Francisco’s new Transbay Transit Center
  • More San Francisco destinations for AC Transit buses
  • MacArthur Blvd. bus ramp connection to I-580 near the Oakland/Emeryville border
  • I-80/Powell Street ramp improvements
  • All-electronic “open-road” tolling on Dumbarton and San Mateo-Hayward bridges

Alternatives considered, but not recommended, by the 2012 Bay Crossing Study Update include:

  • New highway/transit bridge or tunnel connecting Interstate 238 in the East Bay and Interstate 380 on the Peninsula
  • Widening of San Mateo-Hayward Bridge
  • Dumbarton Bridge approach improvements
  • New BART crossings

Take a look at the many alternatives we studied. Download the study.