Emergency escape roof hatches are used to evacuate school buses in rolled-over orientations. In the United States, the minimum opening size of a roof hatch is defined by Federal Motor Vehicle Safety Standard (FMVSS) no. 217. With the prevalence of rising obesity rates among children, the minimum roof hatch opening size may not be large enough to accommodate larger passengers. Post-accident conditions such as injuries, disorientation, and exit obstructions may also prevent unobstructed passage for egress within acceptable time limits. The purpose of this study was to redesign and fabricate a roof hatch with a larger opening and evaluate its egress characteristics for a range of typical school bus passengers. The larger roof hatch opening allows greater evacuation flow rates, and is almost functionally equivalent to the evacuation flow rate of the front door on an upright school bus.

紧急逃生车顶舱口用于以翻转的方向疏散校车。在美国，车顶舱门的最小开口尺寸由美国联邦机动车安全标准（FMVSS）编号为。217.随着儿童肥胖率上升的普遍性，最小的舱口开口尺寸可能不足以容纳更多的乘客。事故后的状况，例如受伤，迷失方向和出口障碍物，也可以防止在可接受的时间内无障碍地通过出口。这项研究的目的是重新设计和制造具有较大开口的车顶舱口，并评估其对一系列典型校车乘客的出口特性。较大的车顶舱口开口允许更大的疏散流量，