Increasing evacuation flow through school bus emergency roof hatches

Area of Science:

• Vehicle safety engineering
• Human factors in transportation safety
• Emergency egress systems

Background:

• Emergency escape roof hatches are critical for school bus evacuation in rollover incidents.
• Current Federal Motor Vehicle Safety Standard (FMVSS) no. 217 minimum opening sizes may be inadequate for a growing child population and post-accident conditions.
• Factors like passenger size, injuries, disorientation, and obstructions can impede timely egress.

Purpose of the Study:

• To redesign and fabricate a school bus roof hatch with an enlarged opening.
• To evaluate the egress characteristics of the redesigned hatch for diverse passenger sizes.
• To assess the impact of the larger opening on evacuation flow rates.

Main Methods:

• Fabrication of a prototype roof hatch with a larger aperture.
• Egress testing with a range of representative school bus passengers.
• Measurement and comparison of evacuation flow rates through the redesigned hatch versus standard hatches and front doors.

Main Results:

• The redesigned larger roof hatch demonstrated significantly greater evacuation flow rates.
• The egress capacity of the enlarged hatch was found to be nearly equivalent to the front door evacuation rate in an upright bus.
• The improved design facilitates more efficient passage for a wider range of passenger sizes.

Conclusions:

• Enlarging the roof hatch opening is an effective strategy to improve emergency egress from school buses.
• The redesigned hatch addresses potential limitations of current standards concerning passenger size and egress efficiency.
• This enhancement offers a vital safety improvement for school bus occupants during emergencies.