Research in freight transportation focuses on the integration of cutting edge economic principles into freight transportation modeling, so that a complete picture could be developed on the broader impacts of transportation activity on the economy and the environment. This research takes place in two major fields: freight transportation demand modeling, and sustainable freight systems. The work on freight demand modeling focuses on enhancing the realism of spatial price equilibrium (SPE) models, and development of simplified modeling techniques. The work on sustainable freight policy studies the interactions between the agents (e.g., shippers, carriers, receivers) involved in freight activity, to define ways to exploit these interactions to foster sustainable development and operations.