The U.S. National Transportation Safety Board (NTSB) determined that the probable cause of the crash was the failure of one of the drivers to keep his vehicle right of the center line.
At approximately 3:20 pm, Conger, driving his tractor-trailer northbound, crossed the center line and struck the school bus.
Reportedly, Conger was alive at during the time of the initial impact, but died due to multiple chest injuries, combined with the fire that broke out in his cab.
[2] Robbie Bass, 10 years old, died the evening of June 2 at Duke University Hospital, bringing the death toll to a total of seven.
The team found that the driver of the Military Distributors tractor-trailer had, during a momentary lapse in alertness, crossed the center line into the path of the school bus.
As a result of its investigation, the NTSB recommended that states end the "issuance of licenses for the operation of large commercial trucks and vehicles capable of transporting more than 10 passengers to persons with diagnosed seizure disorders.