This work addresses the distribution of warehouses and distribution centers (W&DCs) influenced by e-commerce, through spatial analysis and econometric modelling. Specifically, this work analyzes the concentration of W&DCs in various metropolitan planning organizations (MPOs) in California between 1989 and 2016-18; and studies the spatial relationships between W&DC distribution and other demographic and environmental factors through econometric modeling techniques. The work conducts analyses to uncover common trends in W&DC distribution. The analyses used aggregate establishment, employment, and other socio-economic information, complemented with transportation related variables. The results: 1) confirm that the weighted geometric centers of W&DCs have shifted slightly towards city central areas in all five MPOs; 2) W&DCs show a non-decreasing trend between 2008 and 2016; and 3) areas with more serious environmental problems are more likely to have W&DCs. A disaggregate analyses of properties sold and leased in one of the study regions shows a trend where businesses are buying or leasing smaller facilities, closer to the core of consumer demand. Among other factors, the growth of e-commerce sales, and expedited delivery services, which require proximity to the customers, may explain these trends. The study results provide insights for planners and policy decision makers, and will be of interest to practitioners, public and private entities, and academia. Caltrans, MPOs, and affiliated institutions of the National Center for Sustainable Transportation will directly benefit from the results as they want to avoid equity issues brought by the fast development of e-commerce, and its potential impact on W&DC distribution
