Though most Americans hold pro-environmental attitudes, an attitudes-behavior gap exists with respect to vehicle ownership. Significant constraints appear to prevent most people with environmental concerns from buying smaller, more fuel-efficient, less-polluting vehicles. But researchers have only a simplistic understanding of what those constraints are and how individuals describe and react to them. This study explored these barriers in depth through a series of focus group discussions with 36 residents of the Sacramento, California, metropolitan region who held pro-environmental attitudes. Analysis of the focus group conversations revealed that the features of vehicles currently on the market, family and work responsibilities, residential choices, and routines and preferences all constrained participants’ vehicle purchase choices to ones which, more often than not, poorly reflect their environmental attitudes. The group conversations also revealed serious misunderstandings about the environmental impacts of owning and using vehicles that make it difficult for many to accurately assess their alternatives. For some participants, environmental concerns are unlikely to influence future vehicle purchase decisions, even if constraints were removed altogether; other priorities have taken and will take precedence over the environmental impacts of their choices. But for many participants, strategies to remove or weaken the identified constraints to owning smaller and more fuel-efficient vehicles could lead them to choose vehicles that would reduce their resource and energy consumption for personal transportation. Further research with a larger pool of subjects is needed to confirm whether the focus group findings apply to the larger population.