One aim of the scientific and industrial automotive research is the development of applications that enhance both safety and traffic efficiency. Vehicular communication based on wireless short-ranged networks (Vehicle-2-X Communication) provides the foundation for these applications. For example, an obstacle warning application can inform other vehicles in its neighbourhood about a potentially dangerous situation before the obstacle is visible to them. Field tests are carried out to evaluate the improvements that could be achieved by these new applications. However, detailed simulations have to precede tests in the real world. Currently, different kinds of simulators are necessary for the simulation of vehicular communication. Traffic simulators are used to generate the movement of vehicles. In general, traffic simulators have no or only rudimentary functionality for the simulation of direct and multi-hop vehicular communication. Therefore, network simulators are used to simulate the communication between vehicles. They simulate all aspects of the behaviour of a wireless network, such as medium access control, signal strength, and propagation delays. Moreover, an environment generator is used to provide real road maps and an application interface simulator allows the integration of applications designed for real vehicles. One key requirement is the interaction at runtime of the simulation between all components because modifications of traffic parameters, like movements of vehicles and characteristics of roads, need to be made at runtime. For example, when an obstacle warning application of a vehicle detects a dangerous situation, this vehicle sends a warning message to vehicles in its neighbourhood using the network simulator. As a result, receivers of this warning could, then, change their routes, which has to be fed into the traffic simulator.
