Understanding Road Congestion as an Emergent Property of Traffic Networks

Despite a considerable amount of research into the modelling of traffic flow through road networks, a clear understanding of the conditions that cause and exacerbate urban road congestion remains elusive. This paper presents a novel approach to this problem, by identifying congestion as an unintentional emergent property of driver-to-driver interactions. It is described how human interaction is a constant and important intrinsic property of city driving, and how these interactions can lead to explicit phenomena. A framework is presented for the further analysis of congestion at three spatial levels, and the driver behaviours that may be of most significance at each described. Building on this model, the paper presents a case study carried out at the highly congested Blackwall Tunnel in London. In providing evidence for some of the concepts described in this paper, the case study demonstrates how human behaviour causes the emergence of road congestion. The concepts and framework presented in this paper represent a strong starting point for further understanding and eventual modelling of the occurrence and spread of road congestion.