In support ofthe Federal Transit Administration (FTA) Electric Drive Strategic Plan (EDSP), this report assesses state-of-art advances inlithium-ion batteries, ultracapacitors, and relatedpower management and controltechnologies for the rechargeable energy storage systems (RESS) on-board existing and emerging electric drive buses. RD&T roadmaps for near-, mid-, and long-term are developed for FTA and potential partners developing next generation electric drive buses, based on a review of technical literature, and inputs from experts and transit stakeholders regarding lessons learned, knowledge gaps, and priority RD&T needs. Illustrative projects up to 2020 are proposed based on the identified priority needs in these roadmaps. They promise to advance RESS technologiesfrom research, development, demonstration, test and evaluationto full integration in more fuel efficient, environmentally sustainable, and cost-effectivecommercial electric drive transit buses.