(Reuters) - A trucker had driven more than 350 miles and worked over seven hours towing two semi-trailers when his vehicle crossed a California highway median and slammed into a bus full of high school students this month, killing 10 people, a preliminary report showed on Friday.
But the report by the National Transportation Safety Board did not say whether the FedEx driver had become distracted or lost consciousness or whether a mechanical failure had occurred when his truck swerved across the median.
Among the dead in the fiery April 10 crash in the city of Orland, an agricultural community north of Sacramento, were five Los Angeles-area students on their way to tour a Northern California university campus, as well as their chaperones and both drivers.
"The fire consumed the combination vehicle and partially burned the motor coach," the report said.
Friday's report said the truck driver left a FedEx facility in Sacramento at 10 a.m. the day of the crash and delivered two trailers to the city of Weeds, about 230 miles north.
There, the driver swapped out his 28-foot trailers for two new ones and was headed back to Sacramento.
At about 5:40 p.m, while traveling south on Interstate 5, the truck gradually veered left and crossed a 58-foot wide median, planted with a row of oleander bushes, before entering oncoming traffic lanes, the report said.
The truck swiped a Nissan sedan with two passengers, who were not seriously injured, before colliding with the tour bus, the report said. The vehicles caught fire and flames engulfed the truck and partially burned the bus.
In addition to the 10 people who died, more than 30 bus passengers "received injuries of varying degree," the report said.
The students had been on their way to visit Humboldt State University in Arcata, California, as part of a program to help disadvantaged college hopefuls.
The NTSB said information in the preliminary report would be supplemented or corrected during the course of the investigation into the crash.
Editing by Cynthia Johnston and Gunna Dickson