Crowd Evacuation Simulator
A room full of people, one exit, and the clock running: this simulator drives every agent with the social-force model, the standard physics of crowd dynamics. Each person accelerates toward the door at a desired speed, is pushed back by neighbours and walls, and jostles through the bottleneck where clogging arches form and break. Sliders set the crowd size, the door width and the desired speed — push the speed up and you recreate the “faster-is-slower” effect, where a panicked crowd exits more slowly than a calm one. A toggle drops a pillar in front of the exit, the famous counterintuitive trick that can break up arches and improve flow. Readouts track evacuation time, people remaining, and the flow rate through the door in persons per second.
Runs 100% in your browser — simulations are computed locally on your device.
Read the full guide to this tool
Notes
- The social-force model (Helbing & Molnár, 1995) treats each pedestrian as a particle with a goal force, repulsion from others and from walls — enough to reproduce lane formation, arching and clogging.
- Faster-is-slower: above a critical desired speed, pushing harder raises friction and arch stability at the exit, and total evacuation time goes up.
- Clogging arches are the same physics as granular flow jamming in a hopper — people, sand and pills all form load-bearing arches at a narrow outlet.
- An obstacle slightly upstream of the exit can absorb pressure and stagger arrivals, so the door itself stays unjammed — a trick used in real stadium design.
- Runs 100% in your browser — simulations are computed locally on your device.
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