As a programmer who works in a building with one of these -- I've often been quite sure I could code a more efficient system.

It would be pretty fun if someone were to make a version that supported this. :)

I think I read once that when elevators still had operators, larger buildings would have one or more dispatch agents in the lobby that would line people up at the appropriate elevator for the range of floors they intended to visit.

Taller buildings with complex and highly trafficked elevators still do this only using electronics. Employees swipe their badges at a podium which reads what floor they work on and indicates which elevator they should proceed to. The system can intelligently schedule the elevator for that person to use knowing where their destination is.

I'm in a building with a mere nine floors that has such a system (the only buttons in the elevators themselves are door open, door close and alarm). I imagine that the technology will increasingly appear in the smaller buildings as their elevators are built or refurbished.

Whenever I use those sorts of lifts I find it very unsettling - it's interesting, because floor buttons vs external destination buttons give me no more control over the lift, but as a user I become very anxious when my mechanism for "driving" the lift is taken away.

What if you need to visit someone on another floor?

There's touchscreens in the lift lobbies where you can select an override floor before scanning your pass.

I used to work in a 50-story building that had banks of elevators, each of which was hard-coded to only visit the lobby and the appropriate range of floors. For example, the first bank would only visit 2-13, the 2nd bank would visit 14-25, etc. The elevator cars only had buttons inside for the floors they were allowed to visit. There were also a couple service/freight elevators that could visit all floors (including a couple of service/equipment floors that weren't reachable at all by the normal elevators), and had a human operator/guard who logged badge numbers, floors, and property-removal authorization forms.

I think this sort of elevator allocation is fairly common for tall buildings, because it's horribly inefficient for people going to the 44th floor to have to wait while people get on and off at all of the 42 floors in between!

In very tall buildings, to reach the highest floors you might have to take an express car to a higher lift lobby, where you change cars (because it's also inefficient for the 2-13 lift to have an empty shaft that's never used for 80 floors above 13).