It's easy if you try...
I never thought I would see a blog all about buttons, but then came History of the Button.
In this provocative post, our host asks the question, does the elevator user interface need changing? Those who, like me, have waited an hour or more for an elevator going our way at DragonCon might argue that it does. I find myself longing for the days of a human operator who could (a) enforce load limits or (b) keep people from getting on an down-elevator in order to go up. (Aside from the fundamental unfairness of the tactic, it places unnecessary wear and tear on the elevator itself. Or is it not obvious that an elevator that is moving someone in the wrong direction is wasting energy?)
The original "user interface", as I understand it, was a single handle: Moved in one direction, the elevator ascended: In the other, it descended. It was up to the human operator, specially trained for the job, to bring it to a gentle halt with the elevator floor level with that of the desired story of the building.
The problems began when we got rid of that darned operator, put out on the sidewalk to commiserate with the buggy whip manufacturers. The elevator was now controlled by its riders--and a sophisticated set of relays, sensors, and failsafes that (generally) accomplished the task at hand without a human being's constant attention.
Suddenly the question "Is this elevator going up?" was subject to a vote. Every time the door opened. The operator, the final arbiter of the question, was gone--and the elevator itself didn't care. I hope the poor operator at least derived some amusement from the new problems his absence created.
Elevator brains got more and more complex, resulting in a conveyance that would continue rising until it got to the topmost floor to which it was sent (or from which it was called) before it would turn around.
The problem is, the elevator encourages each rider to think only of himself. There's no way to know how many other people want the same floor you do, and nothing to do about it if you did know. With increasingly rare exceptions, there's no way for the average rider to know where the elevator is if he isn't actually on it. PC Tech Support can tell you how long before your call is answered, but nobody can tell you how long before "your" elevator arrives, or how many intermediate stops it will make before it reaches your floor. The user is "protected" from the information he needs to make any kind of intelligent decision regarding the allocation of elevator resources. He's also "protected" from any clues what the elevator system itself is doing, or why.
I'm sure there must have been a few false starts before the familiar elevator interface came together. The rider approaches the lobby and calls an elevator moving in a particular direction, then when one arrives, he gets on and designates his floor. It's a two-step process (unless one happens to be on the topmost or bottommost floor, and so few buildings have their main entrances on either one).
Why should it be two steps?
Back to Bill at the History of the Button, who talks about “destination elevators”. All of the user controls are in each floor's elevator lobby: On the numeric keypad, you tell the system your intended destination floor: It responds by telling you which elevator will go there. There are no buttons in the elevator itself (except, one presumes, the reassuring Emergency Alarm button).
I would love to see a hotel full of science-fiction fans try to cope with elevators like these.