Origins The idea for the Southern Crossing dates back to the 1940s when several additional bridges across San Francisco Bay were studied. After the Bay Bridge crossing opened in 1936, connecting Rincon Hill in San Francisco with the Key Mole in Oakland via two high-level bridges and
a tunnel through
Yerba Buena Island, vehicle traffic exceeded estimates almost immediately; by 1945, even with gasoline rationing, traffic was 191% of the estimates made during planning, and would reach an average of 69,000 vehicles per day by 1946. concluded that a high-level bridge between Hunters Point and Bay Farm Island was feasible at an estimated cost of $53.2M. The 1947 Joint Army-Navy Board considered 29 different alignments before concluding the causeway-tube was the preferred option. This alignment was later named the Parallel Bridge. The main reason to duplicate the existing route was to provide immediate relief to Bay Bridge traffic; the crossing further south from Potrero Point to Alameda was estimated to divert only 20% of existing traffic, and the southernmost proposal studied, from Hunters Point to Bay Farm Island , was estimated to divert only 5% of existing traffic. Preliminary plans for both the Parallel Bridge and Southern Crossing were prepared in 1948, which were reviewed by a board of consulting engineers in 1949. Because both bridges could not be financed simultaneously, the California Toll Bridge Authority resolved to complete the plans for the Parallel Bridge on March 23, 1949. Director Purcell went before Congress in July 1949 to request permission to expand the right-of-way on Yerba Buena Island to allow construction of the Parallel Bridge. The Butterfly Wing bridge was first presented to the public in May 1953 before a sold-out audience at the
San Francisco Museum of Art. A long model of the Butterfly Wing bridge was built for the 1953 presentation; malls, and was included in a traveling exhibition Polivka is credited with piquing Wright's interest in bridge design; they began their collaboration later in 1947, resulting in the Butterfly Wing bridge proposal for the Southern Crossing. The Butterfly Wing design was derived from a crossing designed by Wright in 1947 over the
Wisconsin River near
Spring Green, Wisconsin for the Wisconsin Highway commission. The final design carries six lanes of traffic over twin long diverging arches providing of vertical clearance above the bay's main ship channel. Another source claims the pair of main arches were long and afforded of vertical clearance. The design included a hanging park and parking in the middle of the arched section, making the Butterfly Bridge a destination in addition to a crossing. Polivka and Wright's design, using reinforced concrete, was designed to be half the cost of a conventional steel bridge, provide lower maintenance costs, and resist earthquake damage. However, such proposals never got beyond the drawing board because of cost concerns. The Butterfly Wing bridge design has been revived occasionally since it was first announced; in 1989, the
Oakland Museum of California exhibited the bridge drawings and model, In 1999, the Butterfly Wing design was again promoted, this time as a candidate design for the
eastern span replacement of the San Francisco–Oakland Bay Bridge, winning Oakland mayor
Jerry Brown's support, although by that time, the design had already missed the deadline for replacement proposals, which had been during a three-day workshop held in 1997.
Fourth proposal (1953–58): Potrero Point to Bay Farm Island In 1953, the legislature passed a bill to build the Southern Crossing The western approaches would include connections to the
Bayshore Freeway at 26th Street; the Southern Crossing would also connect with a proposed future freeway at Army Street and an extended
Embarcadero Freeway. The Southern Crossing alignment specified by the legislature had not been previously studied in the 1941 and 1947 reports. According to the
1955 Progress Report, the preliminary plans had been completed and updated cost estimates were available. In March 1956, the
1955 Supplement report was issued covering the legislative amendments made that month changing the San Francisco approaches to the Southern Crossing. The Southern Crossing design was updated again in October 1956; the
1956 Progress Report detailed further changes to the San Francisco and Bay Farm Island approaches mandated by legislative action. By 1956, the Southern Crossing was ready to post requests for bidding; because there was "considerable opposition to raising tolls on the Bay Bridge" from their current , the cost of the Southern Crossing meant the project would have to be built in stages. One key statute passed in the 1957 session imposed a July 1, 1958 deadline; if funding was not finalized for the Southern Crossing by then, the project would be dissolved. Another authorized funds for the construction of the Webster Street Tube without tying it to the larger Southern Crossing project. Under the Minimum Southern Crossing plan of 1957, the same general alignment and design was retained, but the approaches were pruned back to a single interchange near Third and Army in San Francisco and a connection to the Bay Farm Island Bridge in the East Bay. plans made to expand the capacity of existing crossings (plans completed in March 1957 to remove the Key System tracks on the lower deck of the Bay Bridge; additionally, plans completed in October 1958 to double the capacity of the San Mateo Bridge) meant a second crossing was no longer needed. In addition, by this time, plans for the Transbay Tube for public transit service across the Bay had been sufficiently developed to forecast relief for Bay Bridge traffic.
Fifth proposal (1962–72): Southern alignments Three-way bridge and San Mateo County Yet another alternative alignment, proposed in the November 1962
Trans-bay Traffic Study, would connect
India Basin to both Alameda and Bay Farm Island ; the bridge would run to a mid-Bay junction off the southern shore of Alameda and then fork north and east, respectively. The 1962 study also included a more southern alternative alignment between
Sierra Point and Roberts Landing in
San Lorenzo, the first Southern Crossing proposal to include a terminus in San Mateo County. Subsequent public hearings, held in 1964 and 1965, showed strong popular support for both of the two proposed routes, with home geography dictating which route was favored, and in 1965, the legislature authorized a study to compare the two alternatives as well as ferry service. The results of that study were published in the 1966
Southern Crossing of San Francisco Bay report. In San Francisco, Francois and Gonzalez argued the estimated $500 million cost of the Southern Crossing project would be better spent on rapid transit, and Mendelsohn and Pelosi introduced a resolution to require the project to evaluate its impact on BART. Support for the Southern Crossing was largely from legislators representing districts outside the Bay Area; local polls from early 1972 showed that nearly two-thirds of Bay Area residents opposed the Southern Crossing. The scheduled start of construction was delayed until late 1971, and the anticipated completion date was 1975. Because of its potential to siphon riders (and revenue) away from the nascent BART system, the California State Assembly ordered the Toll Bridge Authority to reconsider the Southern Crossing in 1970. In February 1971, the Toll Bridge Authority concluded in a report published after holding two public meetings in San Francisco and Oakland that "It is in the public interest to begin construction on this needed facility [the Southern Crossing] as soon as possible." At the Oakland meeting, held the preceding December, chief engineer E. R. "Mike" Foley of the Toll Bridge Authority argued the Southern Crossing was needed to support cargo traffic and to relieve congestion on the Bay Bridge, but local politicians opposing the new bridge cited pollution concerns and the possibility of increased traffic jams due to
induced demand. The 1971 report concluded that BART revenues would be minimally affected, as the Southern Crossing would provide access to southern San Francisco and northern San Mateo County, while BART would serve
downtown San Francisco instead. Although it passed both houses with overwhelming majorities, AB 151 was vetoed by Governor
Ronald Reagan, who stated the citizens of the Bay Area should be allowed to vote for the approval of the Southern Crossing directly. The Assembly was unable to override the veto, and two regional measures were put on the ballot for six Bay Area counties in the June 6, 1972 election: one that would give the final approval for the Southern Crossing to the legislature, which voters approved, and another (Proposition A) which would issue bonds to fund the Southern Crossing, which was defeated.
Sixth proposal (1989–91): San Bruno/San Leandro In 1989, State Senator
Quentin L. Kopp introduced Senate Concurrent Resolution No. 20, which funded a study to analyze the need for another crossing option (whether tunnel, bridge, or ferry) between Alameda County and San Francisco or San Mateo County. The resulting
Bay Crossings Study was published by the
Metropolitan Transportation Commission (MTC) in 1991 and the scope was not limited to an automobile bridge; the eleven alternatives studied were: • High-Speed Ferry and Operational Upgrade • Southern Crossing Bridge • Southern Crossing tunnel • Interstate 380 to I-238 bridge (with BART) • Interstate 380 to I-238 tunnel (with BART) • BART SFO/OAK airport connection • BART Alameda to Candlestick connection • New BART Transbay Tube • Airport people-mover connection • Railroad Airport connection • Intercity rail connection Of these, the 1991
Bay Crossings Study evaluated five: alternatives 1, 4, 6, 8, and 11. The eight-lane bridge was estimated to cost the most out of all the alternatives studied ($4 B), but would carry the greatest number of trips, providing the most relief to Bay Bridge traffic. in it, MTC concluded that a Mid-Bay Bridge between
Interstate 238 in
Hayward and
Interstate 380 in
San Bruno would cost up to to build. The resulting
San Francisco Bay Crossings Study Update (2012) concluded that due to increased costs no new trans-Bay crossings were feasible. The Mid-Bay Bridge was estimated to cost $12.4 billion, improvements to the San Mateo–Hayward and Dumbarton bridges were estimated at $2.9 billion each, and a second BART tube would cost from $8.2 to $11.2 billion, depending on the alignment. In December 2017, in a letter to the MTC, Feinstein, along with Congressman
Mark DeSaulnier, called yet again for a new span across the Bay. == References ==