This work addresses an important research topic of freight modeling by analyzing the freight patterns, in terms of freight generation and logistics sprawl, of warehouses and distribution centers in Southern California. Specifically, this work analyzes the concentration of Warehouses and Distribution Centers (W&DC) in five counties in Southern California between 1998 and 2014; and explores spatial relationships between W&DC and other industry sectors through centrographic and econometric modeling techniques. Furthermore, the authors estimate factors that explain the concentration of W&DC in the area.
The work uses both disaggregate and aggregate approaches considering the nature of the information available. For the aggregate approach, the analyses used aggregate establishment, employment and other socio-economic data for different industries, complemented with transportation related variables. Using the Commodity Flow Survey (CFS) Microdata and other Census products, the team estimated disaggregate econometric models to characterize the amount of freight generated by NAICS 493 establishments as a function of economic variables of the establishments (i.e., employment).