Analysis of Topological Dynamical Properties of Urban Road Traffic Network

The technologies and applications aiming at the dynamic properties of micro-level road traffic have made plenty of contributions for the development of Intelligent Transportation Systems (ITS) in past decades, which causes a lack of understanding and analysis for the dynamical properties of the whole structure at macro-level. Therefore, in this paper, we construct the Variable-Structure Dynamic Network modle (VSDN) and the Extended Variable-Structure Dynamic Network model (EVSDN) for urban road traffic systems, basing on the Level-Of-Service (LOS) and the traffic reachability. The VSDN model defines the edge set at any time includes only the edges whose LOS lies in un-congestion levels, which causes that the structure of the urban road traffic network varies with time. Furthermore, we extend VSDN to EVSDN that redefines the edge set to combine the micro-level time-varying characteristics into the macro-level topology. The experiments with traffic data and topology data of the Beijing road traffic system show that the EVSDN model is scale-free at some peak-time phases and the appearance of the scale-free property represents the significant change of topological features of urban road traffic networks. During rush hours, the scale-free property can be used to characterize urban road traffic networks.