Network Robustness Index Application at Pikes Peak Area Council of Governments, Colorado Springs, Colorado

Abstract

The evaluation and prioritization of highway segments is a key task in the allocation of transportation planning resources at metropolitan planning organizations (MPOs). The network robustness index (NRI) is a new and evolving transportation planning measure that is based on changes in travel time that result from the removal of one highway link segment. In Colorado Springs, Colorado, the MPO applied the NRI measure, first on the National Highway System (NHS) and then on a small set of highway project links. The use of the NRI on the NHS made clear a ranking system for high-level criticality in the region, with four categories emerging: low, medium, high, and critical. This criticality assessment function of the NRI is effective in road segment evaluation for evacuation, resilience, and emergency preparedness. The NRI was also tested for planning. A small set of regional highway projects was tested with increases in capacity or speed to rank the projects numerically by vehicle hours saved. This use of the NRI may be of value in evaluating regional transportation plan projects. In all, the NRI was found to be a simple, flexible, and practical tool for MPO transportation planning.