The evaluation and prioritization of highway segments is a key task in the allocation of transportation planning resources at Metropolitan Planning Organizations (MPOs). Identification and prioritization of critical highway segments for security and evacuation planning is also an essential element in the 3-C planning processes carried out by MPOs. The Network Robustness Index (NRI) is a new and evolving transportation planning performance metric. The NRI is based on link segment time changes that result from the removal of the candidate link segments, or changes in link capacity or speed. The concept can also be extended to the effect of adding links and/or making changes in link capacity. In Colorado Springs, Colorado USA, the MPO applied the NRI measure, first on the National Highway System (NHS) network, and then on a small set of “significant” highway corridors. Application of the NRI was used initially to assess the roles of the selected facilities in transport system security. Later the NRI was evaluated for feasibility as a performance measure for Regional Transportation Plan project scoring, prioritization and selection for inclusion in the fiscally constrained plan. The application of the NRI to the NHS yielded a clear ranking system for high-level security “criticality” in the region, with four categories emerging: “low”, “medium”, “high” and “critical”. Using this criticality function of the NRI was also effective in road segment evaluation for significant highway corridor project evaluation. Projects were tested using increases in capacity or speed to rank them numerically by vehicle hours saved. These findings suggest that use of the NRI by PPACG may prove to be of value for 2040 Regional Transportation Plan project evaluation and prioritization as well. In all, the NRI was found to be a simple, flexible and practical tool for MPO transportation planning.