Determining the marginal value of improved freight mobility along a corridor requires full information on tonnage, dollar value of freight movements and services used in moving these products and the value-added characteristics of those products. This report investigates whether a practical methodology, applicable in the real world, can estimate value-added components of freight moving on Washington's transportation system. Determining this value-added can be done with the methodology identified in this study though it was found that specific data availability varied heavily from commodity to commodity, from corridor to corridor and project to project. The general results, and restructive assumptions and data deficiencies necessary for statewide analysis, cast doubt on specific findings. Regional or highway segment analysis can be more precise, if the data are locally developed. The basic model, consisting of knowledge about traffic levels, commodity composition, commodity value and value added of the commodity can reveal the importance of a corridor or region of interest to the state's economy.