The confined space of a car and the configuration of its controls and displays towards the driver, offer significant advantages for Augmented Reality (AR) systems in terms of the immersion level provided to the user. In addition, the inherent mobility and virtually unlimited power autonomy transform cars into perfect mobile computing platforms. However, the limited network connectivity that is currently available in automobiles leads to the design of Advanced Driver Assistance Systems (ADAS) that create AR objects based only on the information generated by on-board sensors, stored maps and databases, and eventually high-latency online content for Internet-enabled vehicles. By combining the new paradigm of Vehicular Ad Hoc Networking (VANET) with AR human machine interfaces, we show that it is possible to design novel cooperative ADAS, that base the creation of AR content on the information collected from neighbouring vehicles or roadside infrastructures. We provide a prototype implementation of a visual AR system that can significantly improve the driving experience.