A retrofitted bus featuring a progressive floor elevation system that gradually increases the height of modular flooring sections from front to rear, creating additional underfloor storage space and improving passenger visibility. The bus incorporates elevated passenger seating assemblies with rigid support structures and adjustable footrests for enhanced comfort and accessibility. The retrofitted stowage space may include insulation, climate control, and video monitoring systems. An engine safety cover, constructed from fire-resistant, thermally insulating, and structurally reinforced materials, integrates an extinguishing system for fire suppression. A swing-down egress mechanism at the rear of the bus serves as a structural component during normal operation and converts to an evacuation slide or stairs during emergencies.