title: Demand and Congestion in Multiplex Transportation Networks.
abstract: Urban transportation systems are multimodal, sociotechnical systems; however, while their multimodal aspect has received extensive attention in recent literature on multiplex networks, their sociotechnical aspect has been largely neglected. We present the first study of an urban transportation system using multiplex network analysis and validated Origin-Destination travel demand, with Riyadh's planned metro as a case study. We develop methods for analyzing the impact of additional transportation layers on existing dynamics, and show that demand structure plays key quantitative and qualitative roles. There exist fundamental geometrical limits to the metro's impact on traffic dynamics, and the bulk of environmental accrue at metro speeds only slightly faster than those planned. We develop a simple model for informing the use of additional, "feeder" layers to maximize reductions in global congestion. Our techniques are computationally practical, easily extensible to arbitrary transportation layers with complex transfer logic, and implementable in open-source software.
authors.affiliation: Operations Research Center, Massachussetts Institute of Technology, Cambridge, MA 02139, United States of America.
authors.forename: Philip S
authors.identifier: http://orcid.org/0000-0001-5667-490X
authors.initials: PS
authors.lastname: Chodrow
authors.affiliation: Center for Complex Engineering Systems, King Abdulaziz City for Science and Technology, Riyadh 11442, Saudi Arabia.
authors.forename: Zeyad
authors.initials: Z
authors.lastname: Al-Awwad
authors.affiliation: Department of Civil and Environmental Engineering, Massachussetts Institute of Technology, Cambridge, MA 02139, United States of America.
authors.forename: Shan
authors.initials: S
authors.lastname: Jiang
authors.affiliation: Department of Civil and Environmental Engineering, Massachussetts Institute of Technology, Cambridge, MA 02139, United States of America.
authors.forename: Marta C
authors.initials: MC
authors.lastname: González