An axiomatic design approach to passenger itinerary enumeration in reconfigurable transportation systems

Transportation systems represent a critical infrastructure upon which nations' economies and national security depend. As infrastructure systems, they must be planned and operated to accommodate the uncertain and continually evolving needs of their passengers and freight. New roads are planned or existing roads are closed for maintenance or due to operational breakdowns. Reconfigurable transportation systems are those which adapt to these changes quickly and efficiently. They are not overdesigned with capabilities that may be left unused; instead, capabilities are added only when needed, thus supporting the need for resilient infrastructure. An axiomatic-design-for-large-flexible- systems approach is chosen as a methodology for its deep roots in engineering design. It addresses systems where the functionality not only evolves over time, but also can be fulfilled by one or more system resources, and is used here to enumerate passenger itineraries. This paper builds upon a recent work in which axiomatic design was used to develop a theory of degrees of freedom in transportation systems for their reconfigurable design and operation. The methodological developments are then demonstrated on a small subsection of the Mexico City transportation system to demonstrate its wide-ranging utility in reconfigurability decision-making at the planning and operation timescales. In addition, further comparisons of axiomatic design to traditional graph theory are made, indicating the mathematical basis of the former in the latter.