Solution Algorithm for Long-Haul Freight Network Design Using Shipper-Carrier Freight Flow Prediction with Explicit Capacity Constraints

Abstract

Freight transportation has long been recognized as an important foundation of economic strength. Previous studies used traditional methods such as cost-benefit analysis to examine a set of scenarios. However, because of the complexity of transportation projects that can have substitution or complementary effects in a network, more scenarios may result than can be examined on a case-by-case basis. To realize optimal network design, a branch and bound method is applied to examine all possible scenarios. The work described in this paper focuses on developing public infrastructure investment decisions to improve freight movements. A freight flow prediction model that focuses on the relationship between shippers, who select types of services, and carriers, who decide how to route vehicles, is used to represent freight route choice behaviors. In addition, explicit capacity constraints are used to divert traffic volume from congested links. The benefits and limitations of the method are discussed, its computational efficiency is examined, and a numerical example is provided. The results indicate that project selection by the traditional case-by-case analysis cannot capture the complexity of freight transportation network improvements and yields a suboptimal solution.