Slidewalk

A slidewalk is a fictional moving sidewalk structurally sound enough to support buildings and large populations of travelers. Adjacent slidewalks moving at different rates could let travelers accelerate to great speeds.

They were imagined by science fiction writer H. G. Wells in When the Sleeper Wakes. Robert A. Heinlein made them the instruments of social upheaval in the 1940 short story The Roads Must Roll. Isaac Asimov, in his Robot series, imagined slidewalks as the potential method of transportation of practically the entire urban population on Earth, with expressways moving at up to 60 km/h (37 mph) equipped with seating accommodations for long distance travel, and with slower subsidiary tracks branching off from the main lines. Arthur C. Clarke also used them in The City and the Stars. Larry Niven used them in Ringworld and Flatlander. Slidewalks figure prominently in the animated series "The Jetsons".