Toward a Simple and Universal Law of Pedestrian Behavior

Big city sidewalks can feel like an inexplicable dance of elbows and shopping bags and baby strollers and pigeons and texting. But a group of crowd scientists has whittled the chaos to its core and found that, far from unpredictable, foot traffic follows a mathematical formula elegant for its simplicity. From Shibuya Crossing to Times Square we're all performing invisible calculus: computing other people's speeds and trajectories and adjusting our own accordingly.

Or something like that. In a recently published paper, to be presented this week at a conference, a research team led by computer scientist Ioannis Karamouzas of the University of Minnesota propose "a simple and universal law governing pedestrian behavior." The law suggests our sidewalk interactions are "fundamentally anticipatory in nature"—meaning all those fellow walkers that seem oblivious are actually projecting, and thereby avoiding, future collisions in real-time: