Synopsis: Straying from the Norm in Pedestrian Movements
From far away, bustling crowds of people can appear to move as one. But zoom in and track the motion of individuals, and this apparent synchronicity disappears—everyone’s path is a little bit different, and there is always someone walking against the flow. Federico Toschi, from Eindhoven University of Technology in the Netherlands, and colleagues have now recorded the motions of hundreds of thousands of individuals walking down a corridor to understand just how varied their paths can be. The team’s “crowds” were extremely sparse—just one person walking at a time. But incorporating realistic individual path fluctuations into crowd dynamics simulations should help architects and planners mitigate dangerous congestion at train stations and sports stadia, for example.
The team set up an overhead 3D camera in a corridor connecting the cafeteria at Eindhoven University’s Metaforum building to its dining area. People could enter and exit at both ends of this windowless, poster-bereft, white corridor—Toschi chose this location because of its simple geometry and lack of distractions. For a year the team captured person after person treading this 5.2-meter-long hallway, and extracted their paths from the footage.
As you might expect, most people entered at one end and exited at the other, following similar semi-straight lines down the corridor. But about one in a thousand pedestrians took a sudden U-turn and left from where they entered. The team modeled people as self-propelled particles, showing that path variations and U-turns could be quantitatively accounted for by adding random noise to their velocities. While making quick U-turns isn’t particularly dangerous for lone pedestrians in otherwise empty corridors, such erratic behavior could have ramifications for dense, fast-moving crowds.
This research is published in Physical Review E.
Katherine Wright is a Contributing Editor for Physics.