In this chapter we illustrate the challenges of modeling vehicular motions and introduce the various options that may be found in literature, where models are considered in five categories (pure random, flow, traffic, behavioral and trace-based) as function of their scopes and characteristics. We then describe the most popular vehicular mobility and traffic models available in literature but address them from a networking and application point of view, notably by discussing their interactions with network simulators and emphasizing the role of VANET applications in determining their required level of precision. We introduce three major interaction classes controlling how traffic information is shared with network simulators and conversely how communication information may be used by traffic simulators to improve VANET applications. We finally conclude this chapter by proposing a design framework for the generation of realistic vehicular mobility models depicting the required modeling modules, their level of precision and their interaction capabilities. Our objective is to provide readers with a clear vision of how the various option ... mehrs described in this chapter can be applied for the design of mobility models.