The Coast Guard reported that a freighter hit the rocks west of the Golden Gate Bridge on Tuesday evening. (Photo By Justin Sullivan/Getty Images)
The $116 million Battery Tunnel began construction Wednesday along with an elevated 1,340-foot-long viaduct to take drivers into city.
One tunnel is slated to open on Labor Day 2011 with five lanes that will handle both northbound and southbound traffic, until a second tunnel is built.
The current route between the bridge and downtown San Francisco, Doyle Drive, has been found to be seismically unsafe. The 1.5-mile southern approach to bridge was built in 1936.
The state Department of Transportation has since spent $35 million to strengthen Doyle Drive. But bridge officials say it still could be vulnerable in a large earthquake.