UC Berkeley College of Environmental Design and Civil and Environmental Engineering Professor Marta Gonzalez recently published the article A Simple Contagion Process Describes Spreading of Traffic Jams in Urban Networks(link is external) at Nature Communications. Authors include: Meead Saberi(link is external) (University of New South Wales), Homayoun Hamedmoghadam(link is external) (Monash University), Mudabber Ashfaq(link is external) (UNSW), Seyed Amir Hosseini(link is external) (K.N. Toosi University of Technology), Ziyuan Gu(link is external) (UNSW),Sajjad Shafiei(link is external) (CSIRO), Divya J. Nair(link is external) (UNSW), Vinayak Dixit(link is external) (UNSW), Lauren Gardner(link is external) (Johns Hopkins University), S. Travis Waller(link is external) (UNSW), and Marta C. González(link is external) (UC Berkeley): https://doi.org/10.1038/s41467-020-15353-2(link is external).
The spread of traffic jams in urban networks has long been viewed as a complex spatio-temporal phenomenon that often requires computationally intensive microscopic models for analysis purposes.
In this study, we present a framework to describe the dynamics of congestion propagation and dissipation of traffic in cities using a simple contagion process, inspired by those used to model infectious disease spread in a population. We introduce two macroscopic characteristics for network traffic dynamics, namely congestion propagation rate β and congestion dissipation rate μ. We describe the dynamics of congestion spread using these new parameters embedded within a system of ordinary differential equations, similar to the well-known susceptible-infected-recovered (SIR) model.
The proposed contagion-based dynamics are verified through an empirical multi-city analysis, and can be used to monitor, predict and control the fraction of congested links in the network over time.