The discrete network design problem over time

Abstract

Over time there will be inevitable changes in the travel demand patterns in a transport network. To capture these changing demands and design a gradually upgraded network it is necessary to introduce the time dimension into the transport Network Design Problem (NDP). Previous efforts have extended the continuous network design problem to cater for such considerations. However the continuous problem does not always indicate improvements that are practical. Therefore in this paper we develop a model of the time-dependent discrete network design problem. The importance of the model is illustrated by two numerical studies, which demonstrate the importance of introducing the time dimension to the NDP and the importance of introducing discrete decision variables to the NDP over time. An example on NDP under two cost-recovery principles is also provided to illustrate the application of the model.