Effects of communication efficiency and exit capacity on fundamental diagrams for pedestrian motion in an obscure tunnel - a particle system approach

TL;DR

This study models pedestrian escape from an obscure tunnel using a particle system approach, revealing how communication efficiency and exit capacity influence fundamental diagrams and pedestrian flow behaviors.

Contribution

It introduces a particle system model incorporating communication and exit thresholds to analyze pedestrian dynamics in tunnel escape scenarios, highlighting non-intuitive effects.

Findings

Standard fundamental diagrams are reproduced without communication limits.

Limited communication causes non-monotonic speed-density relationships.

Existence of an optimal pedestrian density for escape efficiency.

Abstract

Fundamental diagrams describing the relation between pedestrians speed and density are key points in understanding pedestrian dynamics. Experimental data evidence the onset of complex behaviors in which the velocity decreases with the density and different logistic regimes are identified. This paper addresses the issue of pedestrians transport and of fundamental diagrams for a scenario involving the motion of pedestrians escaping from an obscure tunnel. We capture the effects of the communication efficiency and the exit capacity by means of two thresholds controlling the rate at which particles (walkers, pedestrians) move on the lattice. Using a particle system model, we show that in absence of limitation in communication among pedestrians we reproduce with good accuracy the standard fundamental diagrams, whose basic behaviors can be interpreted in terms of the exit capacity limitation. When the effect of a limited communication ability is considered, then interesting non-intuitive phenomena occur. Particularly, we shed light on the loss of monotonicity of the typical speed--density curves, revealing the existence of a pedestrians density optimizing the escape. We study both the discrete particle dynamics as well as the corresponding hydrodynamic limit (a porous medium equation and a transport (continuity) equation). We also point out the dependence of the effective transport coefficients on the two thresholds - the essence of the microstructure information.