Freight Analysis Network – Terminal Capacity Estimation
Under a previous research effort, researchers constructed a first generation intermodal freight transportation GIS network to support analysis and forecasting. A merged (all surface modes) network and several related base layers (terminals, environmental, economic and demographic) were brought together into a single routable network layer. Several steps were taken to verify terminal locations and the transportation mode combinations supported therein.
One interesting finding from this research was the number of publicly available freight data products and the difficulties involved in integrating them within a GIS environment. These data products include the Freight Analysis Framework (all modes, U.S. Department of Transportation), Carload Waybill Sample (rail, Surface Transportation Board), Commodity Flow Survey (all modes, U.S. Bureau of the Census), Vehicle Inventory and Use Survey (trucking, U.S. Bureau of the Census), and Manuscript Cargo Files (water, U.S. Army Corps of Engineers). In addition, there are also for-fee databases (e.g., Transearch by Global Insight and the Port Import Export Reporting Service (PIERS) by Global Intelligence Solutions) and various economic data that can be used to further support analysis of intermodal freight movement.
The most challenging task of building an intermodal network is estimating terminal capacity and delay. The network has been designed to accommodate intermodal transfer capacities and costs (time) at the actual location they are incurred (e.g., truck drayage movements). Researchers were able to incorporate very recent throughput times using the AAR performance measures website. Additionally, terminal throughput has been shown to be correlated with the area of the terminal. To this end, terminal boundary areas were digitized using high-resolution satellite imagery.
Supplemental Notes: This research was sponsored by the U.S. Department of Transportation, University Transportation Centers Program (University of Memphis, Intermodal Freight Transportation Institute).