Although school buses statistically are the safest mode of mass transportation, the reported number of pupils injured appears to be increasing faster than the number transported. During the last ten years, clinical interdisciplinary research of vehicular collisions and their attending injuries has contributed significantly to the recent reduction, both absolute and relative, in highway injuries and fatalities. The objective of the UCLA Trauma Research Group (TRG) in the present study was to apply clinical interdisciplinary research methodology to the problem of school bus and coach passenger protection.Current available statistics on bus collision and injury production are reviewed and presented as background material. Pertinent findings of the study include collision causation factors resulting from driver, vehicle, and environmental influences. A major portion of the paper relates injury causation and injury patterns to ejection, restraints, structure design, seats, etc. Occupant kinematics and the subsequent injury production are related to three classes of school bus and coach collisions.Post-collision factors influencing injury, such as egress, extrication, fire, etc., are discussed. Summaries of selected cases are included to illustrate methodology and findings. The paper contains conclusions and recommendations resulting from the statistical review and clinical interdisciplinary study.