Aluminium weighs far less than steel. Your crew lifts the patient, the stretcher and the kit in one movement, so a lighter frame cuts strain on backs and shoulders (a real concern on long shifts).
The metal resists rust too. Ambulances face rain, humidity and constant disinfecting, and a corrosion-resistant frame holds up to that routine.
https://froodl.com/how-an-aluminium-ambulance-stretcher-supports-your-emergency-crew
