  This work explores cascading failures in networked control systems by
employing a platoon of vehicles that exchange information over a time-delayed
communication graph as a model. We study the roles of network connectivity,
system dynamics, communication time-delay, and uncertainty in the emergence of
these failure phenomena. Our results yield closed-form expressions for the
average value-at-risk (AV@R), which we utilize as a coherent risk measure to
quantify the cascading effect of vehicle collisions within a platoon. These
findings are further extended with several standard communication graphs with
symmetries to reveal the impact of graph design parameters on the risk of
cascading collisions. By presenting the boundedness of the steady-state
statistics of the inter-vehicle distances, we present the best achievable risk
of cascading collision with general graph topologies, which is further
specified for special communication graph such as the complete graph. Our
theoretical findings pave the way for the development of a robust framework
designed to mitigate the risk of cascading collisions in vehicle platoons by
exploring how platoon reacts to the various existing failures and the change of
communication links.
