In the last decade there has been a continuous progress in the development of cellular automata models of vehicular traffic. The most recent models are able to reproduce free flow, spontaneous jam formation, synchronized traffic, as well as meta-stability. However, these models have been developed and tested on topologically simple road networks and the translation to large and topologically complex real road networks is non-trivial. In this paper we describe the cellular automaton model we use to simulate the traffic on the autobahn network in North Rhine-Westphalia and discuss some of the challenges that arise when using this model on such a huge and topologically complex network.