The U.S. electric power infrastructure is a significantly underutilized strategic asset which, with the proper shift in operational paradigms could provide a significant portion of the energy requirements for the existing U.S. light duty vehicle (LDV) fleet. This shift would result in reduced emissions, improved economics for utilities, and a reduced dependence on oil. A previous study has shown that the existing generation and transmission assets of the U.S. electric power infrastructure could feasibly supply the electricity for approximately 70% of the U.S. LDV fleet. In the limitations of the distribution system were not explicitly addressed and are more difficult to quantify because of the large diversity of distribution systems topology, design guidelines and load growth. This paper focuses on the impacts of a high penetration of plug-in electric hybrid vehicles (PHEVs) on the distribution systems. Presented are results specific for the Pacific Northwest.