page_title: San Francisco–Oakland Bay Bridge
section_title: Approaches
hierarchical_section_title: San Francisco–Oakland Bay Bridge / History / Approaches
context_page_description: The San Francisco–Oakland Bay Bridge, known locally as the Bay Bridge, is a complex of bridges spanning San Francisco Bay in California. As part of Interstate 80 and the direct road between San Francisco and Oakland, it carries about 260,000 vehicles a day on its two decks. It has one of the longest spans in the United States.
  The toll bridge was conceived as early as the California Gold Rush days, but construction did not begin until 1933. Designed by Charles H. Purcell, and built by American Bridge Company, it opened on Thursday, November 12, 1936, six months before the Golden Gate Bridge. It originally carried automobile traffic on its upper deck, with trucks, cars, buses and commuter trains on the lower, but after the Key System abandoned rail service, the lower deck was converted to all-road traffic as well. In 1986, the bridge was unofficially dedicated to James Rolph.
  The bridge has two sections of roughly equal length; the older western section, officially known as the Willie L. Brown Jr. Bridge, connects downtown San Francisco to Yerba Buena Island, and the newer unnamed eastern section connects the island to Oakland.
context_section_description: The original western approach to (and exit from) the upper deck of the bridge was a long ramp to Fifth, branching to Harrison St for westward traffic off the bridge and Bryant St for eastward traffic entering. There was an on-ramp to the upper deck on Rincon Hill from Fremont Street (which later became an off-ramp) and an off-ramp to First Street (later extended over First St to Fremont St). The lower deck ended at Essex and Harrison St; just southwest of there, the tracks of the bridge railway left the lower deck and curved northward into the elevated loop through the Transbay Terminal that was paved for buses after rail service ended.
  The eastern approach to the bridge included a causeway landing for the "incline" section, and the construction of three feeder highways, interlinked by an extensive interchange, which in later years became known as "The MacArthur Maze".  A massive landfill was emplaced, extending along the north edge of the existing Key System rail mole to the existing bayshore, and continuing northward along the shore to the foot of Ashby Avenue in Berkeley.  The fill was continued northward to the foot of University Avenue as a causeway which enclosed an artificial lagoon, subsequently developed by the WPA as "Aquatic Park".  The 3 feeder highways were U.S. 40 (Eastshore Highway) which led north through Berkeley, U.S. 50 (38th Street, later MacArthur Blvd.) which led through Oakland, and State Route 17 which ran parallel to U.S. 50, along the Oakland Estuary and through the industrial and port sections of the city.
caption: A double balanced cantilever bridge, five truss bridges, and two truss causeways that connected Yerba Buena Island to Oakland. Demolished in 2016.
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