The snarled highways envisioned for the region didn't materialize Monday morning, as many commuters seized on free public transportation, avoided rush hour or just stayed home.
Officials worried the afternoon drive would create bigger problems as traffic leaving San Francisco was diverted away from the collapsed eastbound segment.
"The traffic from the Bay Bridge fans out from across three freeways," said Jeff Weiss, a spokesman for the California Department of Transportation. "Taking away two-thirds of the capacity is really going to cause a bottleneck."
The interchange was destroyed early Sunday when the heat of a burning gasoline tanker truck weakened part of one overpass, crumpling it onto another. The truck's driver walked away with only second-degree burns; no other injuries were reported.
Authorities predicted that overall the crash would cause the worst disruption for commuters since the 1989 Loma Prieta earthquake damaged the Bay Bridge itself.
The sight of the soaring freeway twisted into a fractured mass of steel and concrete was reminiscent of that quake's damage. Originally built in the 1950s, the collapsed roadway was retrofitted in the late 1990s to withstand earthquake damage. Rather than rebuild the ramp to existing blueprints, however, engineers will likely overhaul the interchange to conform to today's more stringent seismic standards. Some 80,000 vehicles used the damaged portion of the road every day. But because the accident occurred where three highways converge, authorities said it could cause problems for hundreds of thousands of commuters. State transportation officials said 280,000 commuters take the Bay Bridge into San Francisco each day. To encourage motorists to switch to public transit, Gov. Arnold Schwarzenegger authorized free passage Monday on ferries, buses and the BART rail system. Extra trains were added and bus and ferry operators also expanded service. Many commuters avoided peak congestion by getting a head start or leaving later than usual, Bay Area Rapid Transit spokesman Jim Allison said. "I did make a little effort to get here a little earlier today because of the freeway melting, or whatever you want to call it," Mark Griffey, who took a BART train into the city, told KTVU-TV. Inspectors X-rayed about a dozen pillars supporting the ramp near the collapsed section to see if they could be salvaged, Weiss said. "Until all the data has been collected, we can't move forward with the design," he said. State officials promised to move swiftly, and observers said the span could be rebuilt in a matter of months. The investigation was still under way, but the California Highway Patrol believes the driver, James Mosqueda, 51, may have been speeding. Investigators do not suspect drugs or alcohol were involved, Officer Les Bishop said. Mosqueda has a history of criminal activity, including drug and burglary arrests, and served two years and eight months in prison following a 1996 arrest for heroin possession, court records show. The state's vehicle code allows convicted felons who have served their sentences to get commercial driver's licenses so long as they have clear driving records, Patrol Chief Steve Vaughn said. Mosqueda remained hospitalized Monday and his family issued a news release, saying: "We are relieved that James is alive and in stable condition. We are grateful that no one else was hurt and thank God that James is on the road to recovery." San Francisco Mayor Gavin Newsom praised the response to the collapse, saying emergency protocols were put into place without major glitches. "This is not a dress rehearsal, it's serious, but we didn't lose any lives," Newsom said. The crash occurred on the MacArthur Maze, a network of ramps and interchanges at the edge of downtown Oakland and about a half-mile from the Bay Bridge toll plaza. Heat exceeded 2,750 degrees, softening and buckling steel beams and melting bolts, California Department of Transportation Director Will Kempton said. The cost of the repairs likely will run into the tens of millions of dollars, and the state was seeking federal disaster aid, Kempton said. (AP) Associated Press writers Aaron Davis, Don Thompson and Juliet Williams in Sacramento, Juliana Barbassa and Scott Lindlaw in San Francisco and Michelle Locke in Berkeley, Calif., contributed to this report. AP-CS-04-30-07 2133EDT