You press a button and wait for your elevator. How long before
you get impatient and agitated? Theresa Christy says 20 seconds.
As a mathematician steeped in the theories of vertical
transportation at Otis Elevator Co., Ms. Christy, 55, has spent
a quarter-century developing systems that make elevators run as
perfectly as possible—which means getting most riders into a car
in less than 20 seconds. "Traditionally, the wait time is the
most important factor," she says. "The thing people hate the
most is waiting." Developed in the 19th century, elevators
transformed urban living, real estate markets and skylines
around the world. As an Otis research fellow, Ms. Christy gets
to work on the toughest problems and on signature projects like
the 1,483-foot-high Petronas Towers in Malaysia, for a time the
world's tallest building. During the recent $550 million upgrade
of the Empire State Building, Ms. Christy was asked whether she
could help get more people up to the observation deck. She said
she couldn't get more p