Alternate capacity reliability measures for transportation networks

Capacity reliability is defined as the probability that the network capacity can accommodate a certain volume of traffic demand at a required service level. It is a supply-side reliability measure for assessing the adequacy of a degradable transportation network. The network capacity model used to calculate the capacity reliability measure is based on the concept of reserve capacity, which requires preserving a pre-determined origin-destination (O-D) demand pattern. In this paper, we relax this assumption by allowing a non-uniform growth in the spatial distribution of the O-D demand pattern. By using this non-uniform O-D growth approach, two network capacity models related to the concepts of ultimate capacity and practical capacity are developed to estimate alternate capacity reliability measures. Numerical results are provided to analyze the features of three capacity reliability measures for transportation networks.