Transportation Supply Design Models

Abstract

This chapter outlines a wide range of methods and mathematical models that may assist the transportation systems engineer in designing projects or other interventions. It should be stated at the outset that supply design models are not meant to “automate” the complex task of design, especially when the proposed actions can significantly alter the performance of the transportation system. In this case, as we have seen, a project may have structural effects ranging from changes in land use to modifications in the level and structure of travel demand. On the other hand, the elements of the transportation supply to be designed may assume a very large number of possible configurations: circulation directions in an urban road network or the lines and frequencies of a transit system are two cases in point. In the presence of such a large number of possibilities, it is practically impossible to explore and compare all the feasible configurations in order to identify the optimum with respect to a given set of objectives and constraints.