The Integrative Freight Market Simulation (IFMS) attempts to depict a comprehensive picture of freight movements, in which both the user side, i.e., commodity flows, and the logistic side, i.e., vehicle-trips, are considered. This framework has the potential to overcome the limitations of both commodity based models and vehicle-trip models. Commodity based models have great limitations in considering the flow of empty vehicles (which are the result of logistic decisions), while vehicle trip models are unable to take into account the economic characteristics of the cargoes.
The IFMS is based on a market equilibrium formulation that depict the competition among freight transportation providers, and a subset of routing problems to represent the actions of these companies when picking up and delivering the goods. The IFMS entails a bi-level approach in which the top level corresponds to the estimation of the provision of service consistent with Cournot-Nash equilibrium, while the bottom level focuses on the construction of tours that satisfy the Cournot-Nash solution and the remaining system constraints, in a context of a large scale simulation-optimization problem. The system constraints have been classified in: a) Primary; and b) Secondary. The primary constraints are: I) freight transportation companies maximize profits in a context of market equilibrium; and II) the user requirements are met, i.e., the commodities produced by and attracted to each zone are transported. Secondary constraints are: III) the resulting trip chains are consistent with known trip chain data; and IV) the resulting commercial vehicle traffic is consistent with secondary data sources, e.g., ITS traffic data. This project will focus on solving the most basic case of IFMS, taking into account the primary constraints (I and II), referred to as the Primary IFMS. This would entail developing solution algorithms that obtain the routing patterns that are consistent with both the Cournot-Nash solution for the provision of service (based on assumed economic parameters) and the user requirements. This will entail the definition of a set of synthetic, though meaningful, test cases that are meant to represent urban areas of different sizes and levels of complexity. These cases will be comprised of a number of data sets: 1. zoning system; 2. set of relevant economic parameters; 3. a set of commercial vehicle operators; 4. a set of user requirements; and, 5. a set of commercial vehicle trips. In other words, a set of synthetic cases for which all relevant information is known will be created. The collaboration of freight industry representatives will be requested to ensure a meaningful and realistic definition of the test cases. Their input is particularly important for the creation of data sets 3, 4, and 5. Algorithms will be developed to solve the Primary IFMS and applied to these test cases. The input data will be comprised of the data sets 1, 2, 3, and 4. The reasonableness and efficiency of the algorithms will be assessed by determining how well they are able to estimate the commercial vehicle trips (data set 5).
This award is made under the Exploratory Research on Engineering the Transport Industries (ETI) program solicitation.
