A tubeway was an ultra-fast mode of transport in the year 2091. It consisted of a network of tunnels that could deliver a vehicle to its destination.
After telling the tubeway robot your destination, you would be accelerated through the tunnel at an incredible speed - so fast, in fact, that the DeLorean time machine's hubcap was left spinning in mid air.
If one did not register their destination with the tubeway robot, a section of tunnel would fold away and their vehicle would be sent to the violation center. The 'violation center' was actually Hill Valley Junkyard.
- The tubeway seems to be the advanced form of the skyway, which in turn was the advanced form of the highway.