The aviation industry realised some years ago that one of the reasons for the limitation on airspace capacity is that the very concept of external air traffic control requires aircraft to fly by regulated routes, traversing named and defined airways, and navigating by named and defined beacons. This entails that all the aircraft in the sky are channelled together into small regions of space, and the minimum safe separation between aircraft then determines the limiting capacity of the airspace.
We have a similar problem in the UK with our ground transport system, namely the road and rail network. The control surfaces of automobiles and trains are assumed to be rotating wheels, and this method of control entails the need for an artificially constructed network of roads and rails. Such a network channels all the cars and trains into small areas of the land surface, and this severely limits the capacity of the ground transport system. The demand placed upon our ground transport system continues to grow, and due to the economic cost and enivronmental implications of building new roads and railways, our ground transport system becomes increasingly inefficient with each passing year.
In aviation, the concept of 'free flight' has been suggested as a partial remedy to the airspace capacity problem. The idea is to make each individual aircraft responsible for its flight-path, rather than an external air traffic controller. Each aircraft is to be equipped with the necessary radar and avionics to predict potential conflicts with other aircraft, and to maintain safe separation. By so doing, aircraft would utilise a larger region of airspace.
I would like to propose that a similar concept of 'free motoring' should be applied to our ground transport network, at least the automobile component of it. I would like to resurrect a suggestion made by Arthur C. Clarke some decades ago, that our favoured form of personalised ground transport should be a hovercraft. (At least, I propose that our ground vehicles should have hovercraft capabilities; the best solution may be a wheeled-hovercraft hybrid). This would instantly free us from our dependency upon a road network, or at least our dependency upon the motorway and trunk-road network between towns and cities. Hovercraft can travel across open land without any need for an aggregated road surface, and without causing any damage to the land. There would be no need for new road-building, and because such vehicles would not be channelled into small areas of the land surface, the capacity of the ground transport system would be boosted. The money currently taken by the Exchequer in the form of road tax and petrol tax, could be used to pay land owners an annual fee for the use of their land.
At the time Clarke proposed his idea, the problem of collisions between such freely driven vehicles would have been insurmountable. Today, the hardware and software being developed for free flight could equally be used to predict and prevent collisions between ground vehicles.