Self-Organization Phenomena in Pedestrian Crowds
  Pedestrian crowds can very realistically be simulated with a social force model which describes the different influences affecting individual pedestrian motion by a few simple force terms. The model is able to reproduce the emergence of several empirically observed collective patterns of motion. These self-organization phenomena can be utilized for new flow optimization methods which are indispensable for skilful town- and traffic-planning. 
Dirk Helbing and Peter Molnar