The National Transportation Safety Board today determined that the probable cause of a school bus crash in Nebraska was the failure of the Nebraska Department of Roads to recognize and correct the hazardous condition in the work zone created by the irregular geometry of the roadway, narrow lane widths, and speed limit.
"School bus safety is one of the Board's top priorities because they carry our most precious cargo," said Chairman Ellen Engleman-Conners. "The Board will continue to aggressively pursue needed safety improvements to prevent these accidents from occurring."
On Saturday, October 13 2001, a 78-passenger school bus carrying 27 high school students and 3 adults (excluding the driver) was traveling westbound through a work zone on U.S. Route 6 in Omaha, Nebraska. As the bus entered the work zone lane shift at the approach to the West Papillion Creek Bridge, it encountered a 52-passenger motorcoach carrying high school students traveling eastbound. Although no collision occurred between the two buses, the westbound school bus departed the roadway and struck a barrier, steered to the left and then steered abruptly back to the right, striking the barrier again and, finally, a three-rail barrier between a guardrail and a concrete bridge railing. The bus passed through the remains of the three-rail barrier, rode up onto the bridge's sidewall, and rolled 270 degrees clockwise as it fell about 49 feet, landing on its left side in the creek below the bridge. Three students and one adult sustained fatal injuries. The remaining passengers and the bus driver sustained injuries ranging from serious to minor.
The Board believes that the failure of the traffic barrier system to redirect the accident vehicle further contributed to the severity of the accident. Also, the accident bus driver's unfamiliarity with the vehicle was a contributing factor.
The Board identified that the Nebraska Department of Roads and the contractor failed to adequately maintain the barrier system on the northeast corner of the West Papillion Creek Bridge, as required by the construction contract. Moreover, had the barrier system struck by the accident bus been repaired to its original design and strength, the bus would probably have been deflected back into its lane and its departure from the bridge avoided, the Board noted.
In the report, the Board stated that the roadway geometry in the work zone created a visual phenomenon that caused the accident bus driver to perceive the oncoming motorcoach as impinging upon its lane. Although it cannot be determined if the oncoming motorcoach crossed the line or not, the narrowness of travel lanes in the work zone relative to the space occupied by the buses left the accident bus driver little room for error.
Investigators found that the accident bus driver was not impaired due to drugs, alcohol, or fatigue. Neither the weather nor the mechanical condition of the bus contributed to the accident. However, the accident bus driver's unfamiliarity with the vehicle, which differed both in its perceptual demands and its handling characteristics from his regular route bus, may have contributed to his inability to accurately judge the lateral distance to the guardrail, bridge rail, and oncoming bus. The Board went on to state that this may have affected the driver's ability to properly steer the bus through the work zone.
As a result of this accident investigation, the Safety Board made recommendations to the Federal Highway Administration, Nebraska Department of Roads, Omaha Fire Department, National Association of State Directors of Pupil Transportation Services, and Thomas Built Buses, Inc. These recommendations deal with proper work zone safety inspections and maintenance, and training emergency responders for extricating passengers from school buses, among other issues.
A synopsis of the accident investigation report, including the findings, probable cause, and safety recommendations, can be found on the Publications page of the Board's web site, http://www.ntsb.gov. The complete report will be available in about six weeks.