| With increasing demand for a more efficient transportation system and decreasing budget level, transportation investment decision-making that aims to select the optimal project portfolio which yields maximized overall networkwide benefits in terms of economy, society and environment has increasingly become important. This dissertation has conducted an in-depth investigation into project evaluation and project selection that are crucial steps of decision-making.;It begins with information search through a review of existing methods for project evaluation and selection. Several limitations of existing methods have been revealed: lack of consideration in the network impacts of a single investment project, interdependencies of simultaneously implementing multiple projects, and restriction of total risk of overall project benefits within an acceptable level. Then, a new methodology has been proposed for networkwide traffic assignment, project evaluation, and project selection.;A state-of-art large scale transportation simulation software, the TRansportation ANalysis and SIMulation System (TRANSIMS) toolbox is utilized to perform networkwide dynamic traffic assignments to general redistributed traffic volumes after implementation of single and multiple projects needed as inputs for project evaluation.;For project evaluation, a life-cycle cost analysis approach is developed to consider all agency costs and user costs in the service life-cycle of two primary categories of highway facilities: pavements and bridges.;For project selection, two-stage enhanced Knapsack model, hypergraph Knapsack, and two-stage hypergraph Knapsack model are proposed to choose the best sub-collection of interdependent projects to yield maximized overall benefits at various budget levels.;Three computational studies have been performed to apply the proposed methodology using two sets of data, including six-year data on 672 candidate projects proposed by Indiana Department of Transportation for state highway programming and 6 mega projects proposed by Illinois State Toll Highway Authority for tollway network major capital improvements. It has generally found that the two-stage hypergraph Knapsack model appears to be most robust in that it could simultaneously resolve the issues of project networkwide impacts, interdependency relationships, and total risks of overall project benefits, thus generating most reliable information to support rational transportation investment decision-making. |
