The Bay Bridge closed at 8 p.m. Thursday night as scheduled, but so far traffic and rapid transit systems are weathering the closure.
Friday morning, the Pleasanton-Dublin BART station parking lots were only three-quarters full with no lines at the entry gates. Next to the station, westbound traffic on I-580, usually at a crawl during the morning peak traffic hour, moved along at 50 mph speeds.
However, that was not the case Friday night as northbound lanes of I-680 and eastbound lanes of I-580 were heavily congested through Pleasanton until 7:30 p.m.
The Bay Bridge replacement project started on schedule, according to California Department of Transportation spokesman Bart Ney. Crews stationed 150 feet in the air began cutting away a double-deck bridge section the size of two stacked football fields and will eventually slide in a prefabricated replacement.
This is the third time in four years that Caltrans has closed the bridge over Labor Day weekend to do important work so that a new, more seismically safe eastern span can open on schedule in 2013. The cost of the entire project is estimated to be $5.7 billion.
Caltrans has been building a new eastern span and upgrading the western side of the bridge in the wake of the 1989 Loma Prieta earthquake, which damaged the bridge and forced it to be closed for a month.
But the closure of the bridge, which is one of the busiest spans in the nation and carries about 280,000 vehicles a day, is the first time it will be closed on a regular commute day for seismic work, Ney said.
The work to replace a section of the Bay Bridge east of the Yerba Buena Island Tunnel to connect the bridge to a temporary detour is one of the biggest and most important parts of the project to build the new eastern span, he said.
Ney said when the work is completed, traffic will flow on a half-mile long replica of the bridge connecting the new eastern span to the Yerba Buena Island Tunnel.
The replacement will allow crews to demolish a portion of the original bridge and build a new, permanent connector from the tunnel to the new eastern span, he said.
Ney said motorists will have to use the half-mile-long detour for three or four years while the old approach to the Yerba Buena Island Tunnel is demolished.
There are "safety concerns" about the detour because it has sharp, S-shaped curves, Ney said. As a result, the speed limit on that section will be reduced from 50 miles per hour to 40 mph and it will be strictly enforced.
Ney said Caltrans was able to reopen the bridge 11 hours ahead of schedule on Labor Day weekend in 2007 but he said the construction work this year will be more challenging than last time.
The cost of putting in the new section has increased dramatically in the last several years, from $34 million to $140 million.
Ney said one reason the cost increased so much is that design changes were made after engineers determined that more should be done to prevent the bridge from collapsing in a major earthquake.
Another reason is that it was decided that more steel should be used for the project and the cost of steel escalated, he said.