Adding mode choice alternative into transportation network redundancy analysis

Redundancy analysis, as an important concept in resiliency analysis, has been recently considered by Xu et al. (2018) by providing two network-based measures to systematically characterize the redundancy of transportation networks. The route diversity measure evaluates the existence of multiple routes between each origin-destination (O-D) pair for travelers, and the network spare capacity measure quantifies the network-wide residual capacity with consideration of congestion for planners. In this paper, mode choice option is also considered in the redundancy analysis for the multi-modal transportation network. Hence, the route diversity measure is extended to the travel alternative diversity measure to consider both route and mode availability, while the network spare capacity measure is expanded from a single mode transportation network with only route choice to a multi-modal transportation network with both mode choice and route choice in a combined modal split and traffic assignment (CMSTA) problem. Numerical results will be presented to demonstrate how adding mode option can significantly increase the transportation network redundancy.