Challenge: peers on wheels - a road to new traffic information systems

In the context of vehicular ad-hoc networks (VANETs), a number of highly promising convenience applications have been proposed. These include collecting and distributing information on the traffic situation, distributed monitoring of road and weather conditions, and finding available parking places in a distributed, cooperative manner. Unfortunately, all of these applications face major problems when a VANET is used as a means to distribute the required information. In particular a large number of vehicles needs to be equipped with dedicated VANET technology before these applications can provide a useful service. Even if customers were willing to purchase a system which is not immediately useful, it would still take quite some time until the required density of equipped cars is reached. In contrast, affordable always-on mobile Internet access is already mainstream. Such Internet connectivity could be used to build the proposed applications in a different fashion: by using peer-to-peer communication, essentially creating a peer-to-peer network of cars sharing traffic information. This allows to overcome the limitations of VANETs, while it preserves their key benefits of decentralization and robustness. In this paper, we describe the technical challenges that arise from such an approach, point out relevant research directions, and outline possible starting points for solutions.