American cities have gone through major transformation as the automobile has become the primary means of transportation for the masses. This change has come with long-lasting implications for the experience of urban life and for the streets. This dissertation analyzes various livable city advocates' efforts to reshape cities, and particularly, to challenge automobiles' dominant influence on urban form. The analysis first focuses on three carfree-streets events--Critical Mass, Park(ing) Day and Sunday Streets--and later, on the recent physical and social transformations in San Francisco, California. The study examines the implications and limits of carfree-streets events on urban social and spatial justice with mixed research methods.

Each carfree-streets event is different and unique, yet each reclaims public space from automobiles and assumes an underlying need to make cities and urban streets more inclusive of multiple users and uses. Thus, the research is situated at the intersection of discussions about right to the city, public sphere, appropriation of urban space, and the right to green and livable cities. Two foundational theoretical concepts help frame the analysis: "counterspaces" (Lefebvre 1991) and "counterpublics" (Fraser 1992). Analysis of the three carfree-streets events details temporary counterspaces created during the events and the multiple reasons that underlie the carfree-streets counterpublics' interest in alternative uses of streets. Analysis of spatial changes details the City's recently developed programs through which the local government's role is reduced to a manager, and the cost and efforts involved in providing improvements to public spaces are significantly outsourced to community groups, private and civic sector.

I argue that such spatial transformations may indicate an extreme case of neoliberalism in which the do-it-yourself attitude is institutionalized. Further, the marginalized position of non-motorists in the context of their limited access to streets, in contrast to the carfree-streets events' organizers/initiators' considerably powerful standing in society, reveals the complexities of spatial justice. Finally, although the events help alleviate the automobile's hegemony in urban space, and make the city more just and inclusive of non-motorists, the ways in which the City provides new public infrastructure might result in social and spatial inequalities in other respects.