Abstract: While studies based on past data trends for hybrid electric vehicles (HEVs) and other fuel-efficient vehicles provide relevant insight, they are of limited applicability for estimating consumer response to the very different conditions associated with current-day adoption of plug-in hybrid electric vehicle (PHEV) technology. The plug-in technology offers new challenges to market penetration, and environmental attitudes and awareness are also very different than in past decades. While awareness of the role of vehicle emissions in global climate change is high in many parts of the world, it is not clear how consumers will weigh a vehicle’s heuristically perceived benefits against rational financial considerations when making a vehicle purchasing decision. The research goals of this project were: to create a model to study potential PHEV market penetration in the personal transportation sector; to assemble data to properly inform the model; to develop methods for efficient up-scaling of model behavior; to use the model to assess the sensitivities of system behavior to various policies and market conditions; and to understand the regulatory regime necessary to support widespread adoption of PHEVs. Various complex systems modeling approaches were used to tackle these goals. To fill identified gaps in the data, the authors designed, conducted, and analyzed an extensive survey on consumer attitudes towards PHEVs using the Amazon Mechanical Turk crowd-sourcing platform.