I was wondering if anyone had devised an airbrake for a bicycle ? I am a complete technical retard, but thought a simple pump when closed off would stop you quite effectively. Brakes at present rely on friction, therefore subject to wear and tear, heat, failure, whereas an air system would be virtually maintenance-free. In the horrible car industry, they have already developed hydraulic systems for recovering the energy used in braking to be recycled as propulsion. However nothing seems to be happening in bicycle innovations at all.