Executive SummaryThis report synthesizes consumer behavior research as it pertains to the plug-in electric vehicle (PEV) purchase decision process. The purpose is to clarify what is known about the vital role consumers play in the U.S. PEV market as it matures to become less policy-reliant and more representative of the U.S., both spatially and demographically. A more representative PEV market will: help OEMs recoup more of their R&D investments in PEVs; help American consumers access the economic and performance benefits of PEVs; and help the U.S. become more energy independent while improving air quality-related public health and reducing greenhouse gas emissions.This report draws heavily from the marketing literature for its organization and insights. Section 2 introduces the standard five steps of the purchase decision process used in consumer behavior research and introduces important internal and external factors that are likely to affect that decision process. Section 3 provides a review of transportation data and literature that is structured around these five purchase decision steps, namely problem recognition, search (both internal and external), alternative evaluation, purchase, and post-purchase behavior. The final section of the report, Section 4, highlights cross-cutting themes in consumer behavior research that are relevant to the maturation of the U.S. PEV market. It also provides a table that compiles a variety of research topics that would fill important knowledge gaps about the PEV purchase decision process.The report identifies several challenges on the consumer side of the PEV purchase process. These include experience gaps and the need for consumers to make high investments of time and effort in the PEV purchase decision-making process and in post-purchase use. As is true for many purchase decisions, there is potential for negative emotions to arise throughout the PEV purchase decision process and for consumers to have negative purchase consequences. The vehicle purchase context can compound some of these challenges and/or differentiate how they play out with respect to PEV purchases versus traditionally-fueled light-duty vehicle purchases. Relevant contextual elements include: time constraints for purchase; rapid technological change in both PEVs and traditionally-fueled vehicles; and competition between PEVs and traditionallyfueled vehicles that are familiar, high-quality, and prominently advertised by OEMs.Despite these challenges, the report makes clear that there is an increasing value proposition for PEV purchase for a growing group of consumers based on the economic, performance, convenience, psycho-social, and societal benefits of PEVs. To increase public awareness of this value proposition, the report emphasizes the importance of emotional appeals and highlights the possible role of PEV owners in shaping these appeals.iii