Congestion and the Third Dimension

Any time two vehicular routes cross, congestion results. They have to share the capacity of single space, something only feasible to accomplish through time separation: each route taking its turn to cross that space, by traffic signal. Preventing the congestion of intersection between two routes requires shifting the surface transportation system from 2 dimensions into 3: One route must cross over the other, either elevated or subterranean. Doing so is costly: Vehicles are heavy, possible grades are limited.

Some of the most epic public work projects of our age are highway interchanges: Lofting long ribbons of concrete into the sky to permit routes not only to pass over one another, but to permit traffic on those routes to merge and diverge onto one another.

The cost of building all the 'sky bridges' that allow our limited access highway system to function is astronomical, both in terms construction and maintenance, and of the opportunity cost of urban real estate (no highway pays property taxes).

Let us propose an alternate paradigm for urban transportation: Where we reduce congestion of intersecting routes by ascending to the third dimension. Except without the astronomical costs of building the infrastructure to do so. This is what the personal copter would offer.

Imagine an alternate world, the Hindenburg did not burn. Zeppelin development continued, become more comfortable and reliable. The 'anchor masts' at the top of the Empire State Building became the norm for skyscrapers. A continental network of such vertical termini developed. Imagine the emergence of a world where every major skyscraper has a landing pad for multi-rotor copters at the top, an esplanade where the passengers embark and disembark.