ASPRS 2009 Annual Conference Baltimore, Maryland  March 9-13, 2009 A TRANSPORTATION CORRIDOR CASE STUDY FOR MULTI-CRITERIA DECISION ANALYSIS Raviraj Sadasivuni, PhD candidate Charles G. O’Hara*, Associate Professor (corresponding author) Rodrigo Nobrega, Post-Doctoral Research Associate Jeramiah Dumas, Assistant Professor Geosystems Research Institute Mississippi State University Starkville, MS 39759 raviraj@gri.msstate.edu cgohara@gri.msstate.edu * sal@gri.msstate.edu jdumas@gri.msstate.edu ABSTRACT Roadway planning can become a contentious process. Delays to projects are frequently due to opposition, conflicting interests and differing opinions from stakeholders, resource agencies, planning organizations and others. Due to the many factors affecting the decision making process, the lack of a unique solution and the plurality of opinions, computational tools may support conflict resolution and decision making. Multiple Criteria Decision Analysis (MCDA) offers a framework wherein differing opinions concerning priorities and values may be utilized in a structured process that considers decision factors, ranks factor criteria, and allocates weights to factors so that results reflect the appropriate priority of each factor considered. This paper addresses a GIS-based decision making framework focusing on environmental and early planning needs in a high impacted transportation corridors. It contains an implementation of MCDA called Analytical Hierarchy Process (AHP) into a geospatial analysis framework to support geo-spatial decision making in generating and selecting paths for roadway options. In this approach, each decision factor is represented as a thematic geospatial layer with attributes that express criteria being considered. Pair-wise comparisons of criteria give rise to relative ranking of criteria. For each factor, a numerical weight assigning relative priority in the decision process is computed. The weighted factors are then combined resulting in a cumulative cost surface. This cost surface is used to generate a least-cost path between selected locations on the surface. The AHP method was adapted to the selection of alternative alignments for Interstate-269, which bypasses the metropolitan area of Memphis-TN. The results show close similarity to results generated by use of traditional methods, but were generated using automated approaches. The methodology enables transportation alternatives to be generated in an efficient and systematic manner and enables multiple scenarios to be simultaneously considered in the transportation planning process to facilitate decisions. This procedure allows scientists and researchers to provide methods useful to decision makers and stakeholders in a balanced and rational way that helps to avoid conflict. INTRODUCTION Transportation corridor planning involves collaborative decision making among stakeholders who often have conflicting values and objectives. Geographic Information Systems (GIS) are capable of handling massive amounts of data. When coupled with physical or economic models, a GIS may be employed to transform and manipulate spatial and attribute data as needed to express values for evaluation criteria, e.g. the cost of different alternatives, the population exposure to different levels of health risk, and the distribution of road network concentrations in different areas of a city. Through a case-study approach that focuses the application upon evaluating transportation corridor alignment alternatives, this paper builds upon past efforts to combine GIS and Multi Criteria Decision Analysis (MCDA) capabilities to deliver decision support for selecting among transportation alternatives (Malczewski, 1999). Analytic Hierarchy Process (AHP) is a highly precise tool in planning which can be used in resource allocation, benefit/cost