Pruned: Pedestrian Labyrinth
[from] a recently published paper on a largely ignored aspect of crowd behavior: the need to socialize.
Most current models of crowd displacement assume the individuals to act independently, simply trying to reach their destination without collisions. Using video recordings in urban areas, the team of Guy Theraulaz (Research Center on Animal Cognition, CRCA, University of Toulouse/CNRS), in a straight collaboration with Dirk Helbing of the Swiss Federal Institute of Technology in Zürich, showed the 50 to 70% of pedestrians do not move alone but in small groups of 2 to 4 people. The study of the spatial organisation within these groups reveals that they walk side by side as long as space allows it, but switch to more complex shapes when crowding increases, with the central persons waking behind the others. This leads ot V shapes in groups of three and U shapes in groups of 4. While these configurations facilitate the communication within the group, they slow down the whole group speed. These concave configurations simply make straight walking ahead more tedious and complicate avoidance manoeuvres. On the whole crowd scale this leads to a roughly 17% traffic reduction compared to a situation where pedestrians move independently.
As with many efforts to understand how crowds behave in urban environments, how they are affected, for instance, by bottlenecked entrances, dueling streams of pedestrian traffic and “turbulence” in shoulder-to-shoulder mobs, this new model of crowd dynamics will help urban planners develop safer and more flock-friendly public spaces.