We now describe a new transportation network performance measure that can be used to
evaluate the efficiency of a transportation network as well as the importance of its network
components. It contains the Latora and Marchiori (2001) measure used in the “complex”
network literature, as a special case. The measure, due to Nagurney and Qiang (2007),
has the additional notable feature that it is applicable, as is the accompanying importance
definition of network components, even in the case that the network becomes disconnected
(after the removal of the component).