Innovation and NYC subway don't usually come together but something changed in the past year or so. One of the greatest life-changers has been the installation of countdown clocks in many of the stations, telling riders how long till the next (several) trains arrive. Now there is a smartphone app for this. (link)
Readers of Chapter 1 of Numbers Rule Your World learn the concept behind these countdown clocks as a "congestion management" tool. It turns out that the psychology of waiting is as important as the mathematics of queuing. A minute of waiting is not the same as a minute of waiting. For instance, a minute of waiting when one is uncertain as to how long the total wait would be is much more irritating than a minute of waiting when one knows how long the total wait would be. By installing such clocks, the MTA removes the unknown which causes anxiety.
My life has absolutely improved as a result of these clocks. I feel much calmer knowing when the next train will arrive. The most amazing part of this congestion management tool is that the actual waiting time has not changed at all but the riders perceive their waiting time to have shortened.
Chapter 1 looks at the problem of congestion and how statistical concepts help us understand and tackle the problem.