Providing vehicles with enhanced ability to communicate and exchange real-time data with neighboring vehicles opens up a variety of complex challenges that can only be met by combining different research fronts such as wireless communications, information processing, self-organization protocols and collaborative optimization. The difficulty in performing real tests in this area forces the use of computer simulation. In this paper we introduce an efficient simulation framework for large scale vehicle-to-vehicle (V2V) networks in urban environments. Our main contribution is a sophisticated traffic simulator, which is oriented towards simulating car-to-car communications, and relies on a global positioning server in order to convey location information for micro-simulated vehicles. To illustrate the various studies made possible by our simulation system, we provide a preliminary characterization of how the wireless transmission range in an urban-like environment affects the freshness and inter-vehicle propagation characteristics of real-time mobility information.