The Road most Travelled: The Impact of Urban Road Infrastructure on Supply Chain Network Vulnerability

Making a supply chain more resilient and making it more efficient are often diametrically opposed objectives. Managers have to make informed trade-offs when designing their supply chain networks. There are many methods available to quantify and optimise efficiency. Unfortunately the same cannot be said for vulnerability and resilience. We propose a method to quantify the impact that a supply chain’s dependence on the underlying transport infrastructure has on its vulnerability. The dependence relationship is modelled using multilayered complex network theory. We develop two metrics relating to the unique collection of shortest path sets namely redundancy and overlap. To test the relationships between these metrics and supply chain vulnerability we simulate progressive random link disruption of the urban road network and assess the impact this has on Fully Connected, Single Hub and Double Hub network archetypes. The results show that redundancy and overlap of the collection of shortest paths are significantly related to supply chain resilience, however under a purely random disturbance regime they hold no predictive power. This paper builds a foundation for a new field of inquiry into supply chain vulnerability by presenting a flexible mathematical formulation of the multilayered network and defining and testing two novel metrics that could be incorporated into supply chain network design decisions.