Oh wow, this is perfect reading for me. One of my first college career fair questions was "Tell me how you would program an elevator". Forgot what sad attempt at an answer I gave, but I pretty much thought about that algorithm every time I've ever waited for the elevator. Which was pretty much daily when living in NY.

This is a fun simulation to play with. One variable I appreciate in efficient elevators is how the doors work. Usually they don't let you press the button to open a closing door - effectively delaying an already departing car

You have no idea how excited I was to see this article today. I've long been fascinated with elevators and the algorithms that control them. Thank you!

One case not covered, I believe I saw at London Heathrow was where 4 cars essentially moved people across only 2 floors. With only 1 centralized button, only 1-point-something car was effectively moving people on average, because people had to wait for the currently filled car to have its doors closed and starting to move, before hitting the button to call the next car to pick them up. Imaging 100-200 people in line and, often, overly eager would-be elevator passengers hitting the button too early. Thus leading to halting the just filled car and doing an additional full open and close doors cycle. Fun stuff!

Reminds of something I haven't thought about in a very long time... SimTower

I recently wrote an article about this problem, and detail one reasonable algo for minimizing wait time. (Doesn’t consider concept of cars being full though, interesting addition)

https://jslandy.com/elevators/

I feel like most cases of wait times are due to elevators "waiting" empty in the wrong floor. They either all wait in the bottom floor, or all wait where they were last left at. Would be better if their waiting floors were distributed throughout the floors so that first response is fast.

> This counterintuitive result is all thanks to the rebalancing step where every 5 seconds, the system re-optimizes each elevator's path. The kiosk enforces rigidity, you must get in the assigned elevator.

Sounds like destination dispatch would work better if it didn't tell you which elevator to get into until the elevator arrived.

EDIT: already being discussed in the thread at https://news.ycombinator.com/item?id=49125423

One of the most frustrating assignments[1] (2011) in my computer science education was trying to build a better mousetrap for elevator control.

[1]: https://clarkmoody.com/Moody_AgentBasedElevatorControl.pdf

User experience is not always correlated with metrics targeted by engineers.

I visit a building sometimes with destination dispatch elevators, and with low exposure across multiple years I'm confused every time the elevator I need to take is open behind me.

I once used the paternoster lift in Germany, beats any elevator algorithm efficiency because it's a non-stop "conveyor" with no doors. I still get nightmares about that elevator.