I was in Vienna this weekend. My Tina was running Vienna City Marathon and the rest of the family was keeping her company. There were some 30,000 runners and many more spectators so the finish area was quite packed. Volksgarten was particularly problematic since this fenced garden has only few exits to the Ring. Juno, my older daughter, and I have squeezed through the fence doors quickly, while my other girls got stuck in the crowd. While waiting for them to come across, Juno and I were observing the bottleneck. The gate was not so narrow and there weren't so many people to justify such a slow moving queue. But people inside the Volksgarten were pushing to come out, while people on the outside pushed to come in. Observing this, Juno asked:
Why do they squeeze, daddy? If they would take turns everybody would come through much faster.
My daughter was right, of course. If there would be a semaphore, people would be able to enter and exit the Volksgarten with substantially less waiting. I explained to my daughter that every person in the crowd is doing what he thinks is the best for him, but in total everybody is worse off because they don't think about what's the best for everybody.
Crowd "decision making" is a fascinating thing, that is as inefficient today as it was hundreds and thousands years ago. But since everybody in the crowd had at least one mobile phone, we could do much better now. I'm pretty sure with the right application, it might be possible for this crowd of some hundred people to make a much more efficient decision that blindly pushing through.