Traffic began moving across the span after two rods and a crossbar were replaced and passed vibration and other tests, said Bart Ney, a spokesman for the state transportation department.

"I know that it's been difficult," he said. "But we're happy to be returning the Bay Bridge to public service."

Cars lined up at the toll plaza shortly before the opening. The first vehicles allowed to cross the bridge's upper deck were led by a line of California Highway Patrol cars.

The span was closed for nearly six days after 5,000 pounds of metal came crashing down into rush-hour traffic Tuesday evening when the two rods and crossbar failed. The parts had been installed over the Labor Day weekend to repair a crack.

One person sustained minor injuries and three cars were damaged when the metal fell.

Workers installed new rods, but a test Saturday showed the rods were rubbing against metal, which could cause them to fail, said Lauren Wonder, a spokeswoman for the state department of transportation.

The parts had to be reworked on Sunday.

The new fix includes anti-vibration dampeners and measures to prevent parts from falling on the bridge if they fail again, Ney said.

The closure -- the longest since the bridge was shut down for a month after the 1989 Loma Prieta earthquake -- had snarled traffic on area roads, as the roughly 280,000 commuters who use the bridge each day looked for alternate routes.

The Bay Area Rapid Transit Agency ran longer trains and provided overnight service over the weekend.