Improving the System Design and Evaluation Process by the Use of Trade-Off Information

A description of two methods of analyzing multidimensional alternatives in the design and evaluation process, applied in the context of future transportation systems for the Northeast Corridor. The first method develops and exhibits feasible/acceptable ranges of values for use in reducing the complexity of a potential selection process. The second method utilizes an indifference analysis or tradeoff approach to improve understanding of the relationship among attributes as viewed by various user, operator, and societal groups. Tradeoff curves are shown in terms of both equal preference and equal budget for various mixes of technical possibilities. When these two families of curves are considered together they provide a line of optimal design which can highlight a specific system design goal. This portrayal of the interaction between evaluation and design considerations can be helpful throughout the process of design improvement.