Statewide Programming: Implementing Transportation-Policy Objectives

Abstract

This paper reviews several prominent state of the practice prioritization methods, describes the ranking methodology for highway mobility improvements used by the Washington State Department of Transportation (WSDOT), and presents empirical results. The new mobility prioritization methodology constitutes a flexible, inclusive framework for assessing independent projects relating to all highway modes and responding directly to state policy goals. It uses a mathematical ranking algorithm to determine the optimal priority order of projects for programming on the basis of cost-efficiency, degree of community support, environmental impacts, mode integration, and land-use-plan compatibility. Because dollar values cannot be assigned to a full range of quantifiable criteria, the project benefit cost ratios are supplemented by the other four categories of risk criteria with disparate unit measures. Based on the first year of implementation, a strict adherence to priority order using the WSDOT prioritization method results in a slightly lower overall program cost-efficiency than might otherwise be achieved by optimizing the program's net present value. The overall effect is minor, but the nonmonetary criteria do improve the priority order of several projects while lowering the rankings of other projects. From a practical standpoint, the methodology is a tool for selecting a subset of highway mobility projects that provides increased knowledge of investment trade-offs given the budget constraints.