The development of new design concepts for school bus body structures and for passively restraining school bus passengers were the major objectives of the program. Passenger protection in front and rear rigid barrier impacts and in a side impact with a rigid pole - all at a 30 mph impact velocity - were the design goals. A unitized bus configuration was specified wherein the body and chassis frame are a single integrated structure in contrast to the typical school bus configuration where the body is bolted onto a chassis frame. Analyses and development tests indicated the feasibility of providing a uniform level of protection to seated occupants, ranging in size from a 6 year old child to a 50th percentile adult male in the front and rear impacts. In the side impact with a rigid pole at 30 mph, the hazard zone existing in the vicinity of the impacted area precludes uniform levels of protection for all occupants. Design layouts of 55-passenger operational school bus incorporating the unitized body structure and passive restraint systems were prepared.