Crowd dynamics are highly complex by different self-organization phenomena resulting from the interactions of pedestrians, which may improve or obstruct their flow. Besides formation of lanes of uniform walking direction and oscillations at bottlenecks at moderate densities, it was recently discovered that stop-and-go waves and a phenomenon called “crowd turbulence” can occur at high pedestrian densities.

If things turn out differently than expected or the inexplicable occurs, this implies that our models are wrong or insufficient. In these moments, insecurity and fear arise, which may in turn escalate into panic. We sense that this kind of inconsistency between model and reality is just as dangerous as an actual, dangerous situation.

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