Heterogeneous dynamics through coupling cellular automata models

In certain situations the simultaneous dynamics of two systems influencing each other, for instance due to the fact that they share a portion of space, must be simulated to study the interaction among them. When a CA approach is adopted to model this kind of situation, we must consider that particular care in selecting the proper granularity level in environmental representation and time resolution must be paid. In addition to this, specific interaction rules, "inter-rules", must be defined in addition to the traditional transition function, representing "intra-rules". In this paper we discuss the general issues of the above general scenario and we describe in details a relevant example represented by the dynamical interplay among pedestrians and vehicles in non-signalized crossings.