REGIONAL FREIGHT FLOW ASSIGNMENT USING GEOGRAPHIC INFORMATION SYSTEMS

The movement of freight is an important but often overlooked aspect of the transportation system. While much research and planning has centered on passenger transport, freight demand and modeling have received relatively little attention due to lack of appropriate data from which accurate vehicle flows could be predicted. This report proposes a methodology that can be used to better understand commodity movement. A method for estimating traffic volumes by commodity type on the transportation network from inter-region commodity flow data is presented. This approach was applied to a case study using the Metropolitan Planning Organization, and has been evaluated for effectiveness. Freight tons of different commodities originating, traveling within and ending in the Boston area have been converted to truck numbers and distributed to different areas in the state using industrial employment density as an indicator variable. Truck flows have then been assigned to the highway network using the user-equilibrium technique, and the resulting link volumes have been validated against existing survey counts. On comparison, a large percentage of roads showed that the estimated truck counts were within a tolerable error margin.