Resilient urban forms: A review of literature on streets and street networks

Cities need to build on their resilience to deal with the combined effects of urbanization, changing geopolitical contexts, and climate change. The physical form of cities has significant implications for their capacity to deal with adverse events and changing conditions. This paper focuses on streets as major constituent elements of urban form. It offers a review of the theoretical discussions and empirical evidence on how design and configuration of urban streets and street networks can contribute to/detract from urban resilience. For the purpose of this study, measures related to urban streets are divided into two broad categories: network topology and design and orientation. Network topology is used to represent urban street network as a combination of nodes and links. Relationships between urban resilience and different centrality and connectivity measures related to network topology are discussed. The design and orientation category explores the possible effects of street width, street edges, street canyon geometry, and street layout and orientation on resilience of cities. It is discussed that all topology and design measures have implications for urban resilience. Appropriate physical form of urban streets can contribute to urban resilience by, among other things, ameliorating urban microclimate, reducing energy consumption and its associated Greenhouse Gas (GHG) emissions, enhancing social capital, improving community health and well-being, and facilitating rapid and effective emergency response in the aftermath of disasters. Overall, results provide insights about physical properties that are required to design resilient streets and street networks.