On Building Cooperative Intelligent Transportation Systems over Public Transports

Cooperative Intelligent Transportation Systems (C-ITS) have gained an increasing interest in the last few years. Within these systems, vehicles use wireless communications to cooperatively exchange information in the perspective of enhancing traffic efficiency and comfort. Public transport represents an excellent candidate for C-ITS support. Indeed, unlike private cars, public transport vehicles are inherently cooperative and can be easily augmented with wireless communication capabilities. In this paper, we analyze the communication contact opportunities between public transport buses. Understanding these contacts is a basic building block towards the design and deployment of intelligent, distributed and cooperative applications on top of bus public transport systems. We particularly investigate bus-to-bus contacts in the actual bus public transport of the entire Luxembourg city over a whole day. This city is a representative example of many other European cities. Our study shows that both space and time are chief factors in the characterization of bus-to-bus contacts. Different geographical regions and daytimes show varied contacts properties. Our analysis thus stresses the importance of considering large-scale scenarios when evaluating C-ITS.