The accident occurred in the very heart of an unruly cloverleaf known as the MacArthur Maze, where several major arteries converge at the approach to the Bay Bridge, which connects San Francisco with the cities and suburbs that line the east side of San Francisco Bay.

Image A fiery pre-dawn tanker truck accident caused the collapse of heavily used freeway overpass near downtown Oakland early this morning. Credit... Peter DaSilva for The New York Times

The California Highway Patrol identified the driver of the tanker as James Mosqueda, 51, from Woodland, Calif., near Sacramento. Officer Trent Cross, a spokesman for the highway patrol, said Mr. Mosqueda had just picked up the gasoline from a nearby refinery and was headed to a gas station near the Oakland airport when the accident occurred.

The highway patrol believes that Mr. Mosqueda was heading south on an interchange of Interstate 80 when he lost control in a curve, hit a guardrail and flipped his truck on its side. The tanker exploded, sending flames hundreds of feet into the air, according to witnesses, and quickly buckled a three-lane section of Interstate 580 and caused it to collapse onto Interstate 880 some thirty feet below.

Michael Brown, the commissioner of the highway patrol, said the driver was able to escape the burning truck and apparently hailed a cab in order to go to the hospital. Mr. Brown said there was “no indication of impairment of the driver” by drugs or alcohol, but that some legal issues are outstanding for both Mr. Mosqueda, and the truck’s owner, Sabek Transportation, based in San Francisco.