## Elevator Economics

Where would we be without the elevator?

To deliver a bed, sometimes you need an elevator. It is easy now…but not during the mid-19th century.

When a bed company mechanic, Elisha Graves Otis, was asked to create a freight elevator, he knew he had to solve the snapping cables problem. At the time, a ripped cable meant a terrifying and perhaps fatal descent. So Otis invented the safety brake. To prove that it worked, at NY’s Crystal Palace Exposition, he had someone cut the cable as his stood on a freight platform that was moving downward. Onlookers’ faces turned from horror to smiles as Otis’s safety spring prevented the platform from moving.

Starting with the safety spring, the elevator is really an innovation story. In 1915, Otis figured out how elevator cars could remain level as people entered and left. Today, at Otis Elevator Co., when mathematician Theresa Christy worries about loads, weight and culture count. In the US, she assumes each person will be 22 pounds heavier than someone in China. Combine that with Westerners wanting more personal space in a small enclosure than people in Asia and you can see why worldwide elevators can vary.

In some ways, elevators just represent one huge math problem. Explained by *WSJ*, when someone on the 6th floor awaits an elevator, if it stops and then goes straight down to one, that passenger is happy. But what about the people who needed to descend on other floors? In a building with 6 elevators and 10 people waiting on different floors, there are over 60 million possible combinations. Imagine how in Mecca, because of prayers, elevator designers had to plan for peak elevator occupancy at least 5 times daily.

Our bottom line? As the elevator ascended, so too did the US economy. With skyscrapers, cities could grow, retailers could expand upward and bulky freight could move to higher destinations.

A final fact: After 20 seconds, people become impatient waiting for an elevator.

Sources and Resources: This *WSJ* article presents a fascinating profile of Otis mathematician, Theresa Christy while the Otis website has an interesting history of the elevator.