The mathematics of elevators

As a mathematician who works at Otis elevators, Theresa Christy can tell you pretty much everything you want to know about humans and elevators (except why some functional adults still haven’t gotten the message that you let people out before you get in). How long are we willing to wait? How many of us will safely fit into an elevator? And does that close doors button really do anything? The WSJ on: The Ups and Downs of Making Elevators Go.

The challenges she deals with depend on the place. At a hotel in the holy city of Mecca in Saudi Arabia, she has to make sure that the elevators can clear a building quickly enough to get most people out five times a day for prayer.

In Japan, riders immediately want to know which car will serve them — indicated by a light and the sound of a gong — even if the elevator won’t arrive for 30 seconds. That way, people can line up in front of the correct elevator.

• elevators
• Theresa Christy