The bus driver was familiar with the area. No mechanical defects have been discovered in the vehicle. The incident occurred in daylight.

The National Transportation Safety Board (NTSB) investigators have so far been unable to determine what caused a tour bus to leave the roadway in Garfield County, Utah on September 20th, during a Los Angeles – to – Salt Lake City run. The overcorrection that followed led to a crash that killed four of the 30 passengers and injured the rest of the passengers and the driver, 15 of them seriously.

The bus, described as “medium-size” by the NTSB, was operated by American Shengjia, Inc. The passengers were all Chinese nationals, headed for Bryce Canyon, the last stop before Salt Lake City.

The trip was the first time the 60-year-old driver had driven that route for American Shengjia, but he had driven the route several times for another company and was familiar with the area.

How it happened

For unknown reasons, the bus went off the right side of the roadway. When the driver steered left to return the vehicle to the roadway, the bus began to cross into the westbound lane. The driver then steered sharply back to the right. The bus began to roll left. As it rolled over, the bus’s roof struck the guardrail next to the westbound lane, significantly crushing the roof (as shown above). The bus rolled one complete revolution before coming to rest on its wheels.

At its final rest, the bus straddled the damaged guardrail, with its front partially blocking the westbound traffic lane of SR-12. According to preliminary information, 11 passengers were completely ejected and 2 passengers were partially ejected during the rollover.

No defects

The Utah Highway Patrol and the National Transportation Safety Board (NTSB) examined the bus and uncovered no defects that could account for the driver’s loss of control. All rear seating positions were equipped with lap belts, and the driver’s seat was equipped with a lap/shoulder belt. The extent of belt use by the passengers is being examined.

All aspects of the crash remain under investigation as the NTSB determines the probable cause, with the intent of issuing safety recommendations to prevent similar crashes. The NTSB is working in conjunction with the Utah Highway Patrol to compile a complete and accurate account of the crash.