A limousine taking nine women to a hen party erupted in flames, killing five of the passengers, including the bride-to-be, authorities and the mother of one of the survivors has said.
Five of the women were trapped, but the four other women managed to get out after the vehicle came to a stop on the San Mateo-Hayward Bridge, the patrol said.
Rosita Guardiano told the San Francisco Chronicle that the woman for whom the hen party was being thrown was to be married next month. Ms Guardiano said her daughter was one of the survivors.
Investigators have not determined what sparked the fire, but the patrol said the white stretch limo became engulfed in flames after smoke started coming out of the rear of the vehicle.
A photo taken by a witness and broadcast on KTVU-TV showed flames shooting from the back. Aerial video shot after the incident showed about one-third of the back half of the limousine had been scorched by the fire. Its taillights and bumper were gone and it appeared to be resting on its rims, but the remainder of the vehicle did not appear to be damaged.
The driver of the limo - 46-year-old Orville Brown of San Jose - was the only person to escape unhurt. It is not clear how he managed to escape without injury. Investigators on Sunday afternoon were still seeking witnesses, the highway patrol said.
"Four people got out, as far as what was going on inside, I don't know," highway patrol officer Jeremy Lofstrom said. All five women were pronounced dead at the scene.
Ms Guardiano said her daughter - 42-year-old Mary Grace Guardiano - was being treated for smoke inhalation. The three other women who escaped the fire, Jasmine Desguia, 34, Nelia Arrellano, 36, and Amalia Loyola, 48, were taken to hospitals to be treated for smoke inhalation and burns, the patrol said.
Ms Desguia and Ms Loyola were listed in critical condition, said Joy Alexiou, a spokeswoman for Valley Medical Centre. The condition of Ms Arrellano, who was taken to another hospital, was not known.