Update: This article is a revised version of one published earlier Sunday evening.
The Bay Bridge reopened around 8 p.m. Sunday, far ahead of its scheduled reopening at 5 a.m. Tuesday.
The upper deck, containing all westbound lanes, was shut down beginning at 8 p.m. Friday for construction work on the western approach of the new Bridge Bridge, which is being built next to the old one.
"We had some great sun," said Caltrans spokesman Bart Ney, quoted in the San Francisco Chronicle. "It was nothing we could have forecasted, but it allowed us to finish the work quickly. In the long run this will save us a lot of money."
Motorists passing through the toll plaza are asked to drive carefully, since the merge will be different, Bay City News reported. While 20 lanes will still merge down to 5, they will curve slightly to the south, Ney said.
The bridge won't need to be closed again until Labor Day weekend in 2013, Ney said.
"The next time we plan to close the Bay Bridge will be to open the new Bay Bridge, Labor Day weekend 2013," Ney said.
The closure caused a surge of traffic on to the Golden Gate Bridge, with an unofficial count showing that more than 67,600 vehicles going south over the bridge on Saturday, up from 39,799 vehicles on the Saturday of Presidents Day in 2011, said Golden Gate Transportation District spokeswoman Mary Currie, according to Bay City News.