New city streets : the role of urban rail trails in the social and economic vitality of cities

Rail trails—abandoned rail corridors that are repurposed as trails for walking and biking—are increasingly common in the United States and Australia. In cities, rail trails are designed as linear parks, as bicycle superhighways, and as neighbourhood connectors. They function as both active transportation corridors and public space. In this way, they can reproduce aspects of historic urban streets, which were transportation corridors but also spaces for promenade, socialising, and shopping. This thesis examines urban rail trails through this potential as a new kind of city street. This potential is significant, as American and Australian cities struggle to integrate active transportation and to create public spaces that are lively and safe and that contribute to the social and economic life of the city. To analyse rail trails as both transportation and public space, this thesis develops a framework of urban vitality. Urban vitality is defined as a character of a space that encourages economic and social interaction between people. This framework of urban vitality is explored theoretically and practically through the development of three agents: First, territorialisation is the control over a physical space by a government, business, organization, or group; and the imposition of particular set of rules, meanings, and order to the space. Second, friction describes the physical, visual, and social interaction of people and places. These interactions are key to the creation and maintenance of a vibrant public sphere where individuals can come together to form communities. Third, looseness describes spaces where physical design, uses, and management contribute to a sense of freedom and possibility. Loose spaces are marked by a physical environment that can be modified and appropriated; a flexible (or non-existent, or vague) set of guidelines or regulations for the use of the space; and a resultant awareness or tolerance for overlapping and conflicting views. These three agents are independently increased or decreased in urban space through physical design, management practices, and everyday use. They interact with each other, reinforcing or conflicting with each other in different circumstances. This framework of urban vitality and the agents of territory, friction, and looseness are used in the analysis of three case study rail trails in the United States: The Burke-Gilman Trail in Seattle, Washington; the Midtown Greenway in Minneapolis, Minnesota; and the BeltLine in Atlanta, Georgia. The case study trails represent a diverse cross section of urban rail trails, varying by age, by design, and by their relationships to the surrounding urban fabric. The case study analysis leads to a generalised set of observations and findings on creating urban vitality in urban rail trails and other urban public spaces