There are optimizations in most modern group dispatch systems to attempt optimal traffic routing and predictive placement of idle elevators. The fancy stuff OTIS has played with gets into AI, but the simple algorithms work nearly as well.

It's the unpredictability of the system (people holding doors, elevators going out of service, faulty mechanical switches, etc) that makes the algorithm design fun.

Feel free to ask me anything. I used to design elevator group dispatch systems as a side job in college.

The New Yorker had a fascinating article about elevator design a while back:

http://www.newyorker.com/reporting/2008/04/21/080421fa_fact_...