Ansgar Kirchner

Simulation of evacuation processes using a bionics-inspired cellular automaton model for pedestrian dynamics

We present simulations of evacuation processes using a recently introduced cellular automaton model for pedestrian dynamics. This model applies a bionics approach to describe the interaction between the pedestrians using ideas from chemotaxis. Here we study a rather simple situation, namely the evacuation from a large room with one or two doors. It is shown that the variation of the model parameters allows to describe different types of behaviour, from regular to panic. We find a non-monotonic dependence of the evacuation times on the coupling constants. These times depend on the strength of the herding behaviour, with minimal evacuation times for some intermediate values of the couplings, i.e., a proper combination of herding and use of knowledge about the shortest way to the exit.

Friction effects and clogging in a cellular automaton model for pedestrian dynamics

We investigate the role of conflicts in pedestrian traffic, i.e., situations where two or more people try to enter the same space. Therefore a recently introduced cellular automaton model for pedestrian dynamics is extended by a friction parameter mu. This parameter controls the probability that the movement of all particles involved in a conflict is denied at one time step. It is shown that these conflicts are not an undesirable artifact of the parallel update scheme, but are important for a correct description of the dynamics. The friction parameter mu can be interpreted as a kind of an internal local pressure between the pedestrians which becomes important in regions of high density, occurring, e.g., in panic situations. We present simulations of the evacuation of a large room with one door. It is found that friction has not only quantitative effects, but can also lead to qualitative changes, e.g., of the dependence of the evacuation time on the system parameters. We also observe similarities to the flow of granular materials, e.g., arching effects.

Discretization effects and the influence of walking speed in cellular automata models for pedestrian dynamics

We study discretization effects in cellular automata models for pedestrian dynamics by reducing the cell size. Then a particle occupies more than one cell which leads to subtle effects in the dynamics, e.g. non-local conflict situations. Results from computer simulations of the floor field model are compared with empirical findings. Furthermore, the influence of increasing the maximal walking speed vmax is investigated by increasing the interaction range beyond nearest neighbour interactions. The extension of the model to vmax>1 turns out to be a severe challenge which can be solved in different ways. Four major variants are discussed that take into account different dynamical aspects. The variation of vmax has a strong influence on the shape of the flow–density relation. We show that walking speeds vmax>1 lead to results which are in very good agreement with empirical data.

Simulation of competitive egress behavior: comparison with aircraft evacuation data

We report new results obtained using cellular automata for pedestrian dynamics with friction. Monte-Carlo simulations of evacuation processes are compared with experimental results on competitive behavior in emergency egress from an aircraft. In the model, the recently introduced concept of a friction parameter μ is used to distinguish between competitive and cooperative movement. However, an additional influence in competition is increased walking speed. Empirical results show that a critical door width wc separates two regimes: for wwc it leads to a decrease. This result is reproduced in the simulation only if both influences, walking speed and friction, are taken into account.

CA Approach to Collective Phenomena in Pedestrian Dynamics

Pedestrian dynamics exhibits a variety of fascinating and surprising collective phenomena (lane formation, flow oscillations at doors etc.). A 2-dimensional cellular automaton model is presented which is able to reproduce these effects. Inspired by the principles of chemotaxis the interactions between the pedestrians are mediated by a so-called floor field. This field has a similar effect as the chemical trace created e.g. by ants to guide other individuals to food places. Due to its simplicity the model allows for faster than real time simulations of large crowds.

From ant trails to pedestrian dynamics

This paper presents a model for the simulation of pedestrian dynamics inspired by the behaviour of ants in ant trails. Ants communicate by producing a pheromone that can be smelled by other ants. In this model, pedestrians produce a virtual pheromone that influences the motion of others. In this way all interactions are strictly local, and so even large crowds can be simulated very efficiently. Nevertheless, the model is able to reproduce the collective effects observed empirically, eg the formation of lanes in counterflow. As an application, we reproduce a surprising result found in experiments of evacuation from an aircraft.

Simulations of Evacuation by an Extended Floor Field CA Model

The floor field CA model for studying evacuation dynamics is extended in this paper. A method for calculating the static floor field, which describes the shortest distance to an exit door, in an arbitrary geometry of rooms is presented. The wall potential and contraction effect at a wide exit are also proposed in order to obtain realistic behavior near corners and bottlenecks.

Cellular Automaton Simulations of Pedestrian Dynamics and Evacuation Processes

We present applications and numerical results for a bionics-inspired cellular automaton approach to pedestrian dynamics [1,2]. The model is able to reproduce collective effects and self-organization phenomena encountered in pedestrian traffic, e.g. lane formation in counterflow. Here we present an analysis of the quantitative impact of the so-called sensitivity parameters k S and k D during evacuation processes. Furthermore the model is applied to the problem of optimization of evacuation times.

Cellular Automata Simulation of Collective Phenomena in Pedestrian Dynamics

Pedestrian dynamics exhibits a variety of fascinating and surprising collective phenomena. A 2-dimensional cellular automaton model is presented which is able to reproduce these effects in a simple way. Inspired by the principles of chemotaxis the interactions between the pedestrians are mediated by a so-called floor field. This field has a similar effect as the chemical trace created e.g. by ants to guide other individuals to food places. In our case the floor field modifies the transition rates to neighbouring cells such that a motion in the direction of higher fields is preferred. Already the inclusion of only nearest-neighbour interactions allows to reproduce many of the collective effects and self-organization phenomena (lane formation, flow oscillations at doors etc.) encountered in pedestrian dynamics