Week 8 Tutorial: Measuring a Pile-Up

Timing how far a sudden stop propagates through a moving crowd, treating pedestrian flow as a fluid-dynamics problem.

14 September 2027

Activity#

Watch a busy footpath, doorway, or escalator exit for a sudden stop — someone checking a phone, reading a sign — and note how far back the disruption propagates before it clears. In the department’s terms: you are looking for a live Unilateral Flow Interruption, and, if you’re lucky, a clean Margin-Seeking Deceleration Protocol to compare it against.

Record your reaction#

Estimate how many people were caught in the pile-up, and how many of them likely never learned what caused it.

Reflection#

In your own words, explain why the lecture treats crowd flow as a fluid-dynamics problem, and name one place where the analogy breaks down — a fluid has no single person who chose to stop.