PALM SPRINGS, Calif. — National Transportation Safety Board (NTSB) officials said the tires on the motorcoach that slammed into a big rig in Palm Springs on Sunday killing 12 were worn so far below safety standards that the bus could have been taken out of service, NBC News reports.

The NTSB officials said a preliminary examination of the tread on the motorcoach found that multiple tires were worn below safety standards and that it will continue to investigate vehicle conditions as well as driver histories to determine what caused the accident, but cautioned that it could take at least a year for a full picture to emerge.

According to the California Highway Patrol's Border Division there was no indication that the driver, Teodulo Elias Vides, braked before hitting the tractor-trailer, while hospital officials said that the bus model was not equipped with seat belts and that the majority of injuries indicated that passengers were thrown from their seats. For the full story, click here.