National Transportation Safety Board
Office of Public Affairs
Washington, DC - The National Transportation Safety Board today determined that the probable cause of a fatal motorcoach accident in Sherman, Texas, was the failure of the right steer axle tire, due to an extended period of low-pressure operation, which resulted in sidewall, belting, and body ply separation within the tire, leading to loss of vehicle control.
Contributing to the severity of the accident was the failure of the bridge railing to redirect the motorcoach and prevent it from departing the bridge. The lack of an adequate occupant protection system contributed to the severity of the passenger injuries.
The accident occurred on August 8, 2008, when a 2002 56-passenger motorcoach with a driver and 55 passengers on board departed Houston en route to a festival in Carthage, Missouri. About four-and-a-half hours into the trip while traveling northbound in the right lane of U.S. Highway 75, the right steer axle tire failed as the motorcoach approached the Post Oak Creek bridge at a speed of about 68 mph; the bus went through the bridge railing and off the bridge. It fell about 8 feet and slid approximately 24 feet on its right side before coming to rest. As a result of the accident, 17 passengers died. In addition, the driver received serious injuries and 38 passengers received minor-to-serious injuries.
Major safety issues identified by this accident investigation include the following safety issues:
As a result of its investigation of this accident, the Safety Board made eight new recommendations in these five safety issue areas to three Federal agencies: the Federal Highway Administration (FHWA), the Federal Motor Carrier Safety Administration (FMCSA) and the National Highway Traffic Safety Administration (NHTSA.
Two recommendations were made to the American Association of State Highway and Transportation Officials (AASHTO) in the area of bridge railing design and one recommendation to the American Association of Motor Vehicle Administrators (AAMVA) regarding tire pressure monitoring procedures, and one recommendation was made to the motorcoach manufacturer, Motor Coach Industries, Inc., calling for revised vehicle maintenance manuals.
The NTSB also reiterated five previous recommendations made to FMCSA and NHTSA in the areas of drug and alcohol testing and motorcoach occupant protection systems.
A synopsis of the Board's report, including the probable cause and recommendations, is available on the NTSB's website. The Board's full report will be available on the website in several weeks.
NTSB Office of Public Affairs: (202) 314-6100
The National Transportation Safety Board (NTSB) is an independent federal agency charged with determining the probable cause
of transportation accidents, promoting transportation safety, and assisting victims of transportation accidents and their families.