Comment by JumpCrisscross

The next century of personal transportation will be autonomous electric cars for short distances, autonomous regional rail for medium within-density transport (e.g.. interborough or within-the-Bay-Area distances), autonomous electric aircraft for cross-density transport(e.g. New York to the Hamptons or Cupertino to Napa) and cheap windowless airplanes for long distance. The unique aspect of this vision is the reduced role for public transit outside intracity subway and regional commuter rail. Autonomous cars and planes seem to increase road efficiency in a manner that competes effectively with rail for density-crossing transport.