Peri-urban residential neighborhoods at the margins current trends in urban growth: towards sustainable transition paths?

In Switzerland as in most European countries, the last decades of urban development have put much pressure on the environment due to uncontrolled urban sprawl. The existing peripheral residential built-up areas mostly composed of single-family houses are responsible for and subjected to many sustainability issues, which are expected to grow in the short/medium term. Focusing on urban and architectural design, this on-going research investigates possible paths for the future of peri-urban neighborhoods of single-family houses by 2050. The paper presents the intermediary results of several test-applications of prospective scenarios developed for two case studies in the urban region of Lausanne, Switzerland. First, this article briefly introduces the research framework of the peri-urban question in Switzerland by highlighting the specificities of the policy and territorial contexts. Second, it describes the design framework, focusing on the elaboration of a typology of peri-urban neighborhoods of single-family houses used as a preoperational tool to guide the design process. The core of the paper then focuses on the conceptual elaboration of four prospective scenarios foreseeing possible evolutions for peri-urban neighborhoods of single-family houses. To illustrate this approach, test-applications – in terms of urban and architectural design – are conducted in two existing neighborhoods. Finally, a limited list of indicators on density, land use and environmental impacts helps assessing the performances of each applied prospective scenario. The scenarios seek to be operational and feasible in a way to provide a decision support. The preliminary conclusions of the study highlight several initial conditions to bring peri-urban neighborhoods on a path towards sustainable transitions