Travel Importance and Strategic Investment in Vermont’s Transportation Assets

Acknowledgements The author would like to acknowledge VTrans for providing funding for this work. Disclaimer The contents of this report reflect the views of the authors, who are responsible for the facts and the accuracy of the data presented herein. Th e contents do not necessarily reflect the official view or policies of the UVM Transportation Research Center. This report does not constitute a standard, specification, or regulation. In recent decades, the " wear-and-tear " of the last 60 years of travel on our nation's transportation infrastructure has outpaced our ability to maintain our highways. In an environment of scarce public resources, addressing this problem will require a rethinking of our current approaches to strategic transportation planning. As networks become increasingly saturated, focus on the most highly-traveled elements is not enough. New performance measures are required to provide objective information for identifying critical elements in saturated networks under disrupted flow regimes to ensure that scarce resources can be utilized effectively. This project advances a new type of system-wide measurement of link criticality that will provide the tools needed for strategic disinvestment in roads that are not critical to the health and welfare of Vermonters. This new approach requires a paradigm shift in our current planning function and in the methods used to measure the importance of transportation system components. In this research, the Network Robustness Index (NRI) methodology is modified to include a process for considering the reason for travel in valuing roadways in Vermont. In addition, a new planning metric based on critical accessibility to emergency services is introduced, and combined with the NRI to yield a new measure, the access-based NRI (aNRI), that is uniquely suited to disinvestment planning. Based on the statistical evidence presented in this report, the exact method used in valuing travel purposes for the calculation of the modified NRI (mNRI) is critical to the calculation of the least critical links in the roadway network. The statistical test used demonstrated evidence of differences in the rank orders at the bottom of the lists generated by each method. The bottom of the rank orders are presumably the links that are most useful for decision-makers considering disinvestment scenarios, so this finding is very important. All of the ranking methods tested in this study produced more defensible rank ordering of the most and least important links in the network than simply assuming that all trips are equivalent in …