Assessing Surface Transportation Network Component Criticality: A Multi-Layer Graph-Based Approach

As critical infrastructure, surface transportation networks need to be designed not only for safety and efficiency but also for maximum survivability during extreme events such as accidents, natural disasters and malicious events. Surface transportation systems are increasingly dependent on an extensive network of detection, surveillance, communication, and computing devices. It is no longer sufficient to consider the analysis of the transportation network, its components, its communication infrastructure, and its power supply in separation. This paper explores the use of multi-layer graph-based analysis applied to assess surface transportation network component criticality. Three layers of critical infrastructure are analyzed: power, communication, and physical roadway network. Interactions within layers and between layers are identified and the relative criticality of each component in the three layers is quantified as to the component's essentiality in terms of network performance. The analysis provides a simple means of assessing the importance of different components in critical infrastructure layers allowing decision makers to prioritize threat mitigation alternatives.