We present a fluid-dynamic model for the simulation of urban traffic networks with street sections of different lengths and capacities.The model allows one to efficiently simulate the transitions between free and congested traffic based on an integrated Lighthill-Whitham model.On top of this,we observe non-linear dynamic patterns which are produced by the respective network topology.Synchronization is only one interesting example and implies the emergence of green waves.In this connection,we will discuss adaptive strategies of traffic light control which can considerably improve throughputs and travel times,using self-organization principles based on local interactions between vehicles and traffic fights.Similar adaptive control principles can be applied to other queueing networks such as production systems.