The Future(?) of Transportation

Back in the 1950's, several Science Fiction writers "predicted" the future of transportation.  Most of the predictions were way off base.

Robert Heinlein wrote a story called "The Roads Must Roll," in which the premise was that the US would be criss-crossed with belts which rolled on track-like devices.  There would be a series of belts, each one going a bit faster than its predecessor, so riders could step from one to the next until they were travelling at high speed.  At the slow edge, where pedestrians entered the system, they built businesses, such as restaurants, dry-cleaners, shops and theaters.  The story centered on the underside of the roads, the machinery and the workers who kept them running.  Except for airports, this never happened.

There was another story in the '50's which I have been unable to identify, but it predicted that the need for high-speed transportation would become so great that the Interstate highway system would be roofed over and improved so that the lower speed limit would be 600 miles per hour (lots of new technology in the cars, since 600 was the top speed of jet fighters then) and it took years of study and practice to get your driver's license.  The story  revolved around a driver trying to get and then keep his license.  This obviously never happened - the technology and the reflexes aren't there.

Several writers thought that sub-orbital rocket liners would be here by now.  They used them to shuttle characters around the world at high speed, in order to facilitate their action.  I don't know about you, but I wouldn't get on one of those for a million dollars!

Then there were mag-lev trains.  These are trains which are "levitated" over the rails by magnetic force.  This almost eliminated the friction of traveling along and the drag of wheels turning on axles, making the train much more efficient.  We have the technology, and mag-lev trains are currently in use in several countries - alas, not the United States.

Finally, there were predictions of personal flying devices.  Think of the Jetsons, etc.  Strap-on rockets and helicopters, flying cars, hovercraft, inertia-less drive devices and so-on were used in countless stories.  Some of them were actually invented and found to be highly impracticable.  The jury is out on hover craft and inertia-less drives, although it looks like hovercraft will have limited utility due to the wind - although they are in use over water in several places.  Inertia-less drives await the technology.

Can you think of any others?