The Fragile Nature of Road Transportation Systems

Abstract

Traffic demand has been increasing continuously and presents a substantial challenge to the efficiency of traffic control strategies. Meanwhile, the operation of transportation systems is widely believed to display fragile properties, i.e., the loss in performance increases exponentially with the linearly increasing magnitude of disruptions. Currently, the risk engineering community is embracing the novel concept of (anti-)fragility, which enables systems to learn from historical disruptions and exhibit improved performance as disruption levels reach unprecedented magnitudes. In this study, we demonstrate the fragile nature of road transportation systems under demand or supply disruptions. First, we conducted a rigorous mathematical analysis to establish the fragile nature theoretically. Then, by considering real-world stochasticity, we implemented a numerical simulation to bridge the gap between the theoretical proof and the real-world operations. This work aims to help researchers better comprehend the necessity to consider antifragile design for the application of future traffic control strategies.