Instantaneous information propagation in a traffic stream through inter-vehicle communication

The advancement of wireless communication technology has made possible the consideration of inter-vehicle communication as a foundation for developing decentralized advanced transportation information systems that would function as a sort of "internet on the road". In this paper, we discuss the reliability of inter-vehicle communication in a traffic stream, dependent on the distribution of equipped vehicles. With the assumption that information propagation is instantaneous compared to vehicle movements, the reliability is measured by the probability of success for information to travel beyond a location; stochastic models are presented for both uniform and general traffic streams. In the models, the traffic stream is divided into a series of cells based on the transmission range, the structure of possible most-forward-within-range communication chains is clarified, the probabilities for information to travel to and beyond a vehicle at a certain hop are computed regressively, and the lower bound of the absolute success rate for information to travel beyond a point is determined. Based on the models, we examine the performance of information propagation for different penetration rates, transmission ranges, and traffic scenarios that include gaps and shock waves. Finally, some implications and future extensions of this effort are discussed.