LARGE SCHOOL BUS DESIGN VEHICLE DIMENSIONS

A survey of United States school bus operators and manufacturers was conducted to define the larger sizes of school buses in regular use. A mid-60 passenger type-C bus (SB-C) and a mid-80 passenger type-D bus (SB-D) were selected as design vehicles. Both the dimensions (length, width, etc.) and the trace of turning path swept through 90 degrees and 180 degrees right turns were measured. During the field tests, these school buses made turns somewhat sharper than those of the AASHTO design single unit or bus vehicles. Simulation methods such as computer-generated templates replicate the field turns fairly well in mid-turn, but do not well replicate the spiral at the end of a turn. The long overhang of these school bus design vehicles allows the outer rear corner of the vehicle to swing outside the wheel path at the beginning of a turn, and therefore be a design consideration in some situations. Recommended SB-C and SB-D turning path templates were developed and presented.