Stumbled upon this when researching for my employers.
Electric bikes, they can store energy from your ride...the more intensive the ride the more enrgy stored. The bikes then can be folded and carried onto a bus, this bus allows the bikes to be 'docked' and act as seats in their folded state. The more 'energy' the bike has stored the cheaper your fare as the energy acts as currency.
Can you imagine a world like that? Super cool.