Commuters' Choreography

With all this energy and all these people, the question is why there are not more collisions. I'm not talking about people and automobiles, but about people and people. By what strange grace do pedestrians keep from running into each other?

I went to Grand Central Station to try and learn the answer. I observed commuters rushing to their trains, entering from 42nd Street or from the Met Life building, heading in scores of directions at once, never colliding. 

There's an almost balletic precision to the movements, many narrow misses, but somehow people get where they're going without rehearsing any of the bobs and weaves required to do it.

It's worthy of Balanchine: the commuters' choreography.