Modern intelligent transport systems are large, distributed, and at least partially embedded systems. They raise new challenges through safe design because of their characteristics that are not easily managed informal methods. The purpose of this paper is to set up a methodology that selects appropriate techniques for the modeling and analysis of such systems. Our methodology relies on symmetric nets (formerly known as well formed Petri nets). We make intensive use of this formalism's capabilities to scale up analysis and set up a roadmap for the design of dedicated model checkers