It seems like you could dramatically improve the standard elevator system now that microcontrollers make it easy to have what used to be sophisticated control systems and modern power semiconductors make it easy to control large amounts of electrical power at high speeds.

Here’s a braindump. The overlong sentences are probably a symptom of too much coffee.

You’d have an “up” lane on the left and a “down” lane on the right, as in a paternoster or in Hitachi’s system mentioned in https://news.ycombinator.com/item?id=9786871, but the cars wouldn’t stop in them; instead, you’d have a “station” at each floor in between the two lanes for the car to stop in without blocking traffic. (Popular floors, like typically the ground floor, would have several stations.) The cars would be small and light, holding two friends or a parent with some small children comfortably, with seatbelts and a maximum gross weight of maybe 300 kg; you could have a door to keep you from accidentally falling out of the car while it was moving, but it wouldn’t need to be automatic, since if you didn’t manage to get it closed, it would inconvenience only you (and whoever else is waiting to reach your floor, if you’re on a single-station floor.)

Once you are in motion, you continue to your destination floor without stopping; because you are sharing the elevator shaft with other cars, you don’t need to share the elevator car with other people. Your trajectory through spacetime to the destination station is reserved by the control computer before you leave the station, so that other cars will only crash into yours if there is a malfunction, such as a rail jam or a cable break. Much of the time, cars will travel through the shaft in convoys with their bumpers in contact with one another, limited by the speed of the frontmost car, which will greatly limit potential collision damage if a malfunction should happen.

(Probably the optimal number of stations on most floors is two, not one, because with two stations, there will almost always be one unoccupied station that your arrival can be scheduled into.)

Power and non-emergency braking are applied to the cars using the same cable-traction system all current elevators use (except for those shitty Otis hydraulic elevators, and those few rack-and-pinion elevators), but the energy is not applied to or removed from the cable by a motor; it is delivered to your car entirely from counterweights connected to your car’s cable through a system of CVTs and clutches. Low-power electric motors lift spare counterweights continuously to replace energy either lost to friction or stairway descents or currently stored in people or objects that haven’t returned back down to street level.

This system removes electric-power constraints to maximum acceleration, so that a continuous-jerk spline trajectory should allow comfortable ascents and descents with accelerations as large as ±⅓g. For a Burj-Khalifa-scale tower of 900 meters, ⅓g means you can comfortably travel from the bottom to the top, in any of the 100 or so cars, in about 20 or 30 seconds, reaching about 70 MPH in the middle of the trip, ten times normal elevator speed.

(Accelerating 300kg at ⅓g at 70MPH is about 43 horsepower, which is within the range of normal elevator power capacities, so it wouldn’t be impractical to build such a high-speed elevator system without the complicated CVT/clutch system, just inefficient.)

As with public-transit cable-car systems or cable tramways, your car can grasp and release cables dynamically, but it can grasp any of several different cables, allowing us to have more cars running at different velocities than we have cable loops and preventing cable breaks from being an emergency under normal circumstances.

And you would do all of this while taking up only the floor footprint of three small elevator cars on most levels, unlike the Burj Khalifa’s 57 large shafts, which run at one-third the peak speed described here and have to stop frequently because you share the car with a dozen other people.

(If you build a subway along these principles, you could use a 48-volt DC third rail; lightweight four-seat vehicles running on bicycle wheels powered by independent motors in the vehicle, rather than cableways; dirt-floored tunnels, unless you’re below the water table; and stations and lines spaced some 50 meters apart instead of 500.)