This energy technology roadmap focuses on electric and plug-in hybrid vehicles (EV/PHEV), presenting for the first time a detailed scenario for their evolution from annual production of a few thousand to over 100 million vehicles by 2050. It finds that the next decade is a key “make or break” period for EVs and PHEVs: governments, the automobile industry, electric utilities and other stakeholders must work together to roll out vehicles and infrastructure in a coordinated fashion, and ensure that the rapidly growing consumer market is ready to purchase them. The roadmap concludes with a set of near-term actions to achieve the roadmap’s vision.