Highway Special Investigation Report - Bus Crashworthiness

NTSB Number: SIR-99-04
NTIS Number: PB99-917006
Adopted September 21, 1999
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Introduction

School bus and motorcoach travel are two of the safest forms of transportation in the United States. Each year, on average, nine school bus passengers and four motorcoach passengers are fatally injured in bus crashes, according to National Highway Traffic Safety Administration (NHTSA) and motorcoach industry statistics. In comparison, NHTSA statistics show that in 1998 over 41,000 people were fatally injured in highway crashes. Although much has been done to improve the safety of school buses and motorcoaches over the years, the safe transportation of bus passengers, especially students and senior citizens, continues to be a national safety priority. Children and seniors are predicted to be the fastest growing segments of our society, and these groups are the primary users of bus transportation. Therefore, the National Transportation Safety Board initiated this special investigation to determine whether additional measures should be taken to better protect bus occupants.

To address crucial safety questions on bus safety, this special investigation examines school bus and motorcoach crashworthiness issues through the analysis of 6 school bus and 40 bus accidents and through information gathered at the Safety Board's August 12, 1998, public hearing. This report also evaluates the Federal Motor Vehicle Safety Standards (FMVSS) that govern the design of school buses and motorcoaches to determine the effectiveness of these standards and to determine whether further occupant protection measures are needed. Also included here are the results of computer simulations performed to evaluate the safety levels afforded by passenger crash protection systems not currently required for school buses. Further, the report reviews international perspectives on, and developments in, motorcoach occupant protection. Finally, the report addresses data collection issues that are hampering effective accident study. During the Safety Board's discussion of bus crashworthiness issues, this special investigation identifies the following safety issues:

  • Effectiveness of current school bus occupant protection systems;
  • Effectiveness of Federal motorcoach bus crashworthiness standards and occupant protection systems;
  • Discrepancies among different Federal bus definitions;
  • Deficiencies in the National Highway Traffic Safety Administration's Fatality Analysis Reporting Systems bus ejection data; and
  • Lack of school bus injury data.

As a result of this special investigation, the Safety Board makes recommendations to the U.S. Department of Transportation, the National Highway Traffic Safety Administration, the National Association of Governors' Highway Safety Representatives, and the bus manufacturers.

Recommendations

To the U.S. Department of Transportation:

In 1 year and in cooperation with the bus manufacturers, complete the development of standard definitions and classifications for each of the different bus body types, and include these definitions and classifications in the Federal Motor Vehicle Safety Standards. (H-99-43)

Once the standard definitions and classifications for each of the different bus types have been established in the Federal Motor Vehicle Safety Standards, in cooperation with the National Association of Governors' Highway Safety Representatives, amend the Model Minimum Uniform Crash Criteria's bus configuration coding to incorporate the FMVSS definitions and standards. (H-99-44)

To the National Highway Traffic Safety Administration:

In 2 years, develop performance standards for school bus occupant protection systems that account for frontal impact collisions, side impact collisions, rear impact collisions, and rollovers. (H-99-45)

Once pertinent standards have been developed for school bus occupant protection systems, require newly manufactured school buses to have an occupant crash protection system that meets the newly developed performance standards and retains passengers, including those in child safety restraint systems, within the seating compartment throughout the accident sequence for all accident scenarios. (H-99-46)

In 2 years, develop performance standards for motorcoach occupant protection systems that account for frontal impact collisions, side impact collisions, rear impact collisions, and rollovers. (H-99-47)

Once pertinent standards have been developed for motorcoach occupant protection systems, require newly manufactured motorcoaches to have an occupant crash protection system that meets the newly developed performance standards and retains passengers, including those in child safety restraint systems, within the seating compartment throughout the accident sequence for all accident scenarios. (H-99-48)

Expand your research on current advanced glazing to include its applicability to motorcoach occupant ejection prevention, and revise window glazing requirements for newly manufactured motorcoaches based on the results of this research. (H-99-49)

In 2 years, develop performance standards for motorcoach roof strength that provide maximum survival space for all seating positions and that take into account current typical motorcoach window dimensions. (H-99-50)

Once performance standards have been developed for motorcoach roof strength, require newly manufactured motorcoaches to meet those standards. (H-99-51)

Modify your methodology to collect accurate, timely, and sufficient data on passenger injuries resulting from school bus accidents so that thorough assessments can be made relating to school bus safety. (H-99-52)

Require that all school buses and motorcoaches manufactured after January 1, 2003, be equipped with on-board recording systems that record vehicle parameters, including, at a minimum, lateral acceleration, longitudinal acceleration, vertical acceleration, heading, vehicle speed, engine speed, driver's seat belt status, braking input, steering input, gear selection, turn signal status (left/right), brake light status (on/off), head/tail light status (on/off), passenger door status (open/closed), emergency door status (open/closed), hazard light status (on/off), brake system status (normal/warning), and flashing red light status (on/off) (school buses only). For those buses so equipped, the following should also be recorded: status of additional seat belts, airbag deployment criteria, airbag deployment time, and airbag deployment energy. The on-board recording system should record data at a sampling rate that is sufficient to define vehicle dynamics and should be capable of preserving data in the event of a vehicle crash or an electrical power loss. In addition, the on-board recording system should be mounted to the bus body, not the chassis, to ensure that the data necessary for defining bus body motion are recorded. (H-99-53)

Develop and implement, in cooperation with other Government agencies and industry, standards for on-board recording of bus crash data that address, at a minimum, parameters to be recorded, data sampling rates, duration of recording, interface configurations, data storage format, incorporation of fleet management tools, fluid immersion survivability, impact shock survivability, crush and penetration survivability, fire survivability, independent power supply, and ability to accommodate future requirements and technological advances. (H-99-54)

To the National Association of Governors' Highway Safety Representatives:

In conjunction with the U.S. Department of Transportation, amend the Model Minimum Uniform Crash Criteria's bus configuration coding to comply with standard definitions and classifications of buses. (H-99-55)

To the bus manufacturers:

Cooperate with the U.S. Department of Transportation in the development of standard definitions and classifications for each of the different bus body types. (H-99-56)