Simulating Dynamical Features of Escape Panic

Dirk Helbing, Illés Farkas, and Tamás Vicsek

Alex Turek

Stampedes

• People trying to move faster than normal• Physical interactions between people• Uncoordinated passing of bottlenecks• Arching/clogging at exits• Dangerous pressures within jammed

crowd (up to 4,450 N/m)

Stampedes (cont’d)

• Injured/fallen people turn into obstacles• Tendency of “mass behavior,” i.e. herd

instinct• Alternative exits are overlooked or

underused

Studying Stampedes

• Mostly social psychology (mentality of herd behavior)

• Helbing et al. attempted to model them using self-driven particle systems

• Combine socio-psychological and physical forces

A Single Particle

Affected by multiple forces:Desired Velocity and associated acceleration

Interaction forces

Desired Velocity ForceHelbing et al. specified these parameters:

vi0 (Desired velocity)

• 0.6 m/s – Relaxed• 1.0 m/s – Normal• 1.5 m/s – Nervous• >1.5 m/s – Panic (transition to uncoordinated

bottleneck behavior)

Interaction Forces

• Psychological desire to have room between you and another person

• Psychological desire to not be too close to the walls

F

F

Interaction Forces

• Body force – counteracting body compression

• Sliding friction force – counteracting movement tangential to something you’re in contact with

F

F F

Measured Effects: Transition to uncoordination due to clogging

Arch-like bunching, with avalanche effect when arches break (demo)

• Attempting to have too high a vi0

• High interpersonal friction becoming the dominant force at a bottleneck

• Buildup of forces causing extremely high pressures, and injuries (demo)

• Asymmetrical columns can improve outflow and prevent buildup of fatal pressures (demo)

Measured Effects: Faster-is-Slower Effect

• Jamming can occur at widening of escape routes (demo)

Measured Effects: Faster-is-Slower Effect

• Individualism vs. Herd behavior• Each pedestrian may either select individual

direction, follow avg. direction of his neighbors in a certain radius, or a mixture of both, weighted by panic parameter pi. (demo)

Measured Effects: Mass Behavior

Desired direction at time t

• Both have drawbacks:– All individualistic means no one will learn from anyone

else (demo)– All herding means no exploration for other exits

(demo)

Measured Effects: Mass Behavior

Measured DataLeaving time vs. Desired

velocity

Measured DataLeaving time for 80 people, given

different combinations of individualistic and herding behavior

Questions?

Cited Paper:Helbing, Farkas, Vicsek.

“Simulating Dynamical Features of Escape Panic”. 2000

http://www.eecs.ucf.edu/~lboloni/Teaching/EEL6938_2007/papers/Helbing-EscapePanic.pdf

Presentation by Alex Turek