The bridge was opened to traffic on Thursday, November 12, 1936, at 12:30 p.m. The San Francisco Chronicle report of November 13, 1936, read;
"the greatest traffic jam in the history of S.F., a dozen old-fashioned New Year's eves thrown into one—the biggest and most good-natured crowd of tens of thousands ever to try and walk the streets and guide their autos on them—This was the city last night, the night of the bridge opening with every auto owner in the bay region, seemingly, trying to crowd his machine onto the great bridge. And those who tried to view the brilliantly lighted structure from the hilltops and also view the fireworks display were numbered also in the thousands. Every intersection in the city, particularly those near the San Francisco entrance to the bridge, was jammed with a slowly moving auto caravan. Every available policeman in the department was called to duty to aid in regulating the city's greatest parade of autos. One of the greatest traffic congestions of the evening was at Fifth and Mission streets, with down town traffic and bridgebound traffic snarled in an almost hopeless mass. To add to the confusion, traffic signals jammed and red and green lights did not synchronize. Police reported that there was no lessening of the traffic over the bridge, all lanes being crowded with Oakland or San Francisco bound machines far into the night."
The Bay Bridge at night.The total cost of construction for the bridge was $79.5 million (equivalent to $1.07 billion in 2005 dollars). Prior to its opening, the bridge was blessed by Cardinal Secretary of State Eugene Cardinal Pacelli, who later became Pope Pius XII. At completion, the bridge became the longest suspended-deck bridge in the world and the longest cantilever bridge in the world. Because it was in effect two bridges strung together, the western spans were ranked the second and third largest suspension bridges. Only the George Washington Bridge had a longer span between towers.
The western end of the bridge from the air.The original west approach to (and exit from) the upper deck of the bridge was a long ramp which began at Fifth and Bryant Streets. There were also ramps for the upper deck on Rincon Hill at Fremont Street, and ramps for the lower deck at Essex and First Streets. The lower deck ramps, utilized mainly by trucks, were terminal points for the lower deck highway. Beyond them, the tracks of the bridge railway (see below) also left the lower deck, curving northward into a loop through the Transbay Terminal.
There were three original eastern approaches: a viaduct from the end of Cypress Street (State Highway 17) in Oakland; a viaduct from the end of 38th Street (U.S. Highway 50) at San Pablo Avenue in Oakland; and the Eastshore Highway which carried U.S. Highway 40 along the shoreline of Albany, Berkeley and Emeryville.
When the bridge first opened, the upper deck consisted of three lanes of traffic in each direction and was restricted to automobiles only. The lower deck carried three lanes of truck and auto traffic on the north side. The middle of these three lanes was reversed according to the commute direction utilizing traffic lights, but with no divider. Two railroad tracks were built on the south side of the lower deck for the electric commuter trains of the Southern Pacific, the Key System, and the Sacramento Northern, although train service across the bridge did not begin until January 15, 1939. An overhead catenary supplied power to the Southern Pacific and Sacramento Northern trains while a third rail was utilized by the Key trains. After 1941, only the Key System used these tracks. Rail service on the bridge ended in April of 1958.
The highway on the bridge was originally designated U.S. Highways 40 and 50. This was replaced by Interstate 80 in 1964.
The offramps for Treasure Island and Yerba Buena Island are unusual as they are on the left-hand side both in the eastbound and westbound directions. Eastbound and westbound onramps are on the usual right-hand side, but are tricky as the onramps require acceleration from a dead stop to freeway speeds in less than 20 feet.
Automobile traffic increased dramatically in the ensuing decades while the Key System declined, and in October 1963 the bridge was reconfigured with five lanes of westbound traffic on the upper deck and five lanes of eastbound traffic on the lower deck. Trucks were allowed on both decks and the railway was removed. Owing to a lack of clearance for trucks through the upper-deck portion of the Yerba Buena tunnel, it was necessary to lower the upper deck where it passed through the tunnel and to correspondingly excavate the lower portion. This was done while the bridge was in use by using a movable temporary span over the portion being lowered. On the lower deck of the tunnel and its eastern viaduct extension it was necessary to remove central supports, with each transverse beam being doubled to take the load across all lanes. It was also necessary to further reinforce each beam supporting the upper deck throughout the entire span, modifications still visible to the traveler.
The series of lights adorning the suspension cables were added in 1987 as part of the bridge's 50th-anniversary celebration.
Collapsed section of the Bay Bridge after the Loma Prieta earthquake in 1989.During the October 17, 1989, Loma Prieta earthquake, which measured 7.1 on the Richter scale, a 50-foot (15 m) section of the upper deck of the eastern truss portion of the bridge at Pier E9 collapsed onto the deck below, indirectly causing one death (some people claim this was actually due to misdirection of traffic by the California Highway Patrol). The bridge was closed for just over a month as construction crews repaired the fallen section. It reopened on November 18 of that year.
Western Span Retrofitting:
The western suspension span has undergone extensive seismic retrofitting, almost all at a detail level that does not substantially affect (and in some cases improves) the overall appearance.