Highway Freight Flow Assignment in Massachusetts Using Geographic Information Systems

Goods movement is an important aspect of the transportation system. Freight flow, complemented with the much-researched passenger movement, provides a way for understanding the complete vehicle flow scenario on the highways. Commodity movement prediction has not received much attention because of the lack of sufficient and easily accessible data sources. Most data sources give aggregated commodity movements and, because of the heterogeneity of freight, accurate predictions of truck flows have not been possible. A methodology for calculating the truck flows on the various highways in Massachusetts from interstate commodity flow data is presented. Freight tons originating and ending in Massachusetts have been converted to truck numbers by using a quantitative procedure and distributed to different areas in the state by using employment as an economic indicator variable. The truck flow is assigned to the important highways and validated against existing survey counts. On comparison, a large percentage of the roads show the estimated truck counts are within a tolerable error margin. The research also shows that statewide analyses need to be refined near urban areas because of a variety of complexities involved.