Microscopic dynamics of the evacuation phenomena

TL;DR

This study analyzes pedestrian evacuation dynamics using the Social Force Model, revealing how cluster formations influence delays and efficiency during escape, with different behaviors observed at varying anxiety levels and desired velocities.

Contribution

It provides new insights into the microscopic cluster structures and their impact on evacuation regimes, especially distinguishing between 'faster is slower' and 'faster is faster' phenomena.

Findings

Giant clusters characterize the 'faster is faster' regime.

Blocking clusters attached to walls cause delays in the 'faster is slower' regime.

Small clusters are relevant at very low velocities, while larger clusters appear at intermediate velocities.

Abstract

We studied the room evacuation problem within the context of the Social Force Model. We focused on a system of 225 pedestrians escaping from a room in different anxiety levels, and analyzed the clogging delays as the relevant magnitude responsible for the evacuation performance. We linked the delays with the clusterization phenomenon along the "faster is slower" and the "faster is faster" regimes. We will show that the "faster is faster" regime is characterized by the presence of a giant cluster structure (composed by more than 15 pedestrians), although no long lasting delays appear within this regime. For this system, we found that the relevant structures in the "faster is slower" regime are those blocking clusters that are somehow attached to the two walls defining the exit. At very low desired velocities, very small structures become relevant (composed by less than 5 pedestrians), but at intermediate velocities (vd = 3 m/s) the pedestrians involved in the blockings increases (not exceeding 15 pedestrians).