>Lifts are the disruptive technology. They make energetically efficient cities possible and cheap.
Are lifts really as efficient as escalators? An escalator is constantly moving (unless it's malfunctioning), so there is no wait to continue moving. An elevator on the other hand is not. Maybe it depends on the number of floors? I can see an elevator being faster going from ground to floor 40 rather than zig zagging floors from ground to 40. Does anybody use "express" escalators that skip floors allowing for faster transit to higher floors?
> An escalator is constantly moving (unless it's malfunctioning), so there is no wait to continue moving.
That wastes energy but makes it time efficient for users (in terms of latency). OTOH, escalators are slow compared to most lifts/elevators, which means total trip time efficiency isn't good unless you are only going a floor or two or are competing with an elevator that stops a lot, where the latency gain may still beat the loss of vertical speed. Which is why escalators tend to get used where you've got lots of traffic volume but they aren't going up/down lots of floors.
I used to work in an office building with escalators that are powered off at night -- there was some sort of motion sensor about 10 feet before the escalator that would power it on when someone approached, you'd have to be running to reach the escalator before it reached normal speed.
So on-demand escalators are possible, just rare.
In the daytime either they kept them on all the time, or maybe there was enough constant demand to keep them running as I never saw one powered off during the day.
They're more efficient because of reduced frictional losses, the contact point of an elevator is a pulley at the top of shaft and a couple guide rails. The guide rails are mostly there to provide lateral support. As for latency you can design around it, modern tall buildings will usually have multiple elevator banks that service different floors. A lot of engineering can go into designing the dispatching for elevators.
Our hospital used to have lifts that didn't stop at floors. The had no doors, you just jump on them and get off. They were intended for staff only, to quickly get between floors so slightly out of view of the public. They were replaced a few years ago though. Mabe too many accidents?
Are lifts really as efficient as escalators? An escalator is constantly moving (unless it's malfunctioning), so there is no wait to continue moving. An elevator on the other hand is not. Maybe it depends on the number of floors? I can see an elevator being faster going from ground to floor 40 rather than zig zagging floors from ground to 40. Does anybody use "express" escalators that skip floors allowing for faster transit to higher floors?