A relative total cost index for the evaluation of transportationnetwork robustness in the presence of degradable links andalternative travel behavior

摘要

In this paper, we demonstrate how to capture the robustness of a transportation network in the case ofdegradable links represented by decreasing capacities. In particular, with the use of Bureau of Public Roadsuser link travel cost functions, we propose two relative total cost indices to assess transportation networkrobustness in the case of travel behavior associated with either user optimization or system optimization.We derive upper bounds of the relative total cost index for transportation networks with special structure andcongestion parameters under the user optimal flow pattern. We also derive an upper bound for the relativetotal cost index under the system optimal flow pattern for general transportation networks. Numericalexamples are presented for illustration purposes. This research is the first to quantify transportation networkrobustness in the presence of degradable links and alternative travel behavior. This research has implicationsfor transportation planning and management, for vulnerability analysis, as well as for security issues.