  We propose a 2-dimensional cellular automaton model to simulate pedestrian
traffic. It is a vmax=1 model with exclusion statistics and parallel dynamics.
Long-range interactions between the pedestrians are mediated by a so called
floor field which modifies the transition rates to neighbouring cells. This
field, which can be discrete or continuous, is subject to diffusion and decay.
Furthermore it can be modified by the motion of the pedestrians. Therefore the
model uses an idea similar to chemotaxis, but with pedestrians following a
virtual rather than a chemical trace. Our main goal is to show that the
introduction of such a floor field is sufficient to model collective effects
and self-organization encountered in pedestrian dynamics, e.g. lane formation
in counterflow through a large corridor. As an application we also present
simulations of the evacuation of a large room with reduced visibility, e.g. due
to failure of lights or smoke.
