Two UPS employees who were in one of the tractor-trailers were also killed.
Investigators said the bus crashed and rolled before it was struck by the FedEx tractor-trailer. One of the UPS tractor-trailers then crashed into the wreckage. The driver of the car swerved to try to avoid the crash, sliding to a stop next to the UPS truck. The second UPS tractor-trailer also swerved before hitting the car.
CLICK HERE to read the full preliminary report.
Officials said light snow was falling at the time of the crash and the roadway had been treated with salt.
Thursday's report said the NTSB is gathering records on the commercial drivers involved in the crash and is "evaluating occupant protection, human performance, vehicle performance, the Pennsylvania Turnpike Commission's snow- and ice-removal procedures, collision avoidance technology installed on the three truck-tractors, and the safety culture of Z&D Tour."
NTSB officials said, “all aspects” of the crash remain under investigation as they work to determine the probable cause.
Following the release of the report on Thursday, Carl DeFebo from the PA Turnpike Commission released this statement:
The PA Turnpike has worked in close coordination and cooperation with the National Transportation Safety Board and will continue to do so. However, we will await the completion of the investigation and issuance of the final report before commenting further.
Carl DeFebo, PA Turnpike Commission