This paper focuses on the simulation and optimization of car traffic, modelled through a fluid dynamic model, based on the conservation of the cars number. In particular, the case study of the harbour of Salerno, Italy, is presented. Simulations of vehicular flows are carried out by a graphical tool, that allows to reproduce the evolution of densities on the roads of the network through animated and coloured pictures. From the analysis of simulated densities on roads, obtained by a given input configuration for the network object of study, the tool is able to plan some strategies for the improvement of traffic conditions through an optimization routine