Cascading Failure From Targeted Road Network Disruptions

Recent natural disasters have shown that urban road networks are susceptible to cascading failures as evidenced by city scale traffic jams. Further, the rise of internet connected vehicles and smart city infrastructure leads to the potential for hackers and nation states to target disruptions that maximize the potential for cascading failure. Here, we quantify the potential for targeted disruptions on urban traffic networks. Guided by microscopic traffic simulations, we develop a theoretical framework for predicting the growth in cascading traffic jams around disruptions. Application of our framework to previously validated Boston trips reveals that a targeted disruption of roads leads to a disproportionately large proportion of shortest time routes being blocked, due to the relative importance of a few key roads. We find that an initial targeted disruption quickly impacts a significant portion of incoming traffic. Depending on the percentage of initial disruption, vehicle density, and characteristic free flow trip time the cascade occurs on the minutes to hours timescale. However, connected component analysis reveals that route redundancy provides an order of magnitude improvement in fragility, demonstrating the potential for strengthening transportation against network failure.