There are already numerous clever ways to rent out a parking space on land you own. These days, the pressure on parking is so great that even more creative measures can be investigated.
Given the availability of communications, today’s invention is a system which allows anyone in a parking space to make a small amount of money (or phone credit) just by calling a certain number when they are about to leave their current spot. The information about this space is then provided to the nearest subscriber to the service who has just called the system to say they need somewhere to park. This assumes that everyone in the near future will have a GPS streetmap system on board their vehicle.
The usual Council/City parking fees would still apply, of course, but this extra charge would more nearly optimise the use of space and time in getting stopped near one’s urban destination. Subscribers could set triggers in connection with regular or forthcoming visits to some town, but they would still have to get physically near their end-point to be alerted to any suitable vacant bays (indicated on the screen of their in-car navigation device).
A more sophisticated system would require that a departer wait for an arriver before driving off, although that would require a recognition protocol which might be too socially complex to manage.