School bus rear emergency door design improvements to increase evacuation flow

摘要

United States Federal Motor Vehicle Safety Standard (FMVSS) No. 217 specifies the design requirements for school bus emergency exits. One component of a school bus evacuation system requires that the rear emergency door be fitted with a device that is capable of holding the door in an open position at the point at which the door is perpendicular to the rear of the bus body, regardless of the bus orientation. In the case where a school bus is rolled onto the driver's side of the vehicle, the rear emergency door hinge will be located at the top of the door. Due to the substantial weight of the door, pushing the door to the locked open position with the bus in this configuration requires forces that exceed the capabilities, both strength and anthropometry, of many adults and nearly all young children. This would result in the door hanging in the opening of the exit, obstructing the egress of passengers as they attempt evacuation, and increasing the potential for disastrous consequences. The purpose of this study was to design, fabricate, and evaluate an alternative rear emergency door hold-open device that allows the door to be held partially open and provides unobstructed passage. The results revealed that the alternative hold-open device facilitated significantly faster flow rates than the rear emergency door hold-open device currently in use on school buses.