The CarTALK 2000 project aims at the development of new driver assistance systems that are based upon inter-vehicle communication. To this purpose, a mobile ad hoc network (MANET) consisting of vehicles will be developed as the communication platform to support co-operative driver assistance applications. Routing in such a vehicular MANET faces a number of new challenges, in particular due to the extremely dynamic network topology and a large variable number of mobile nodes. Therefore, an efficient and scalable ad hoc routing mechanism is crucial for the performance of the CarTALK 2000 communication system. After analyzing the system characteristics and requirements, this paper introduces a spatially aware routing protocol and a distributed location service. The key of Spatially Aware Routing is to improve position-based routing performance by integrating spatial environment information into routing, such as the underlying road topology.