Unidirectional pedestrian circulation: Physical distancing in informal settlements

The COVID-19 pandemic has resulted in a wide range of spatial interventions to slow the spread of the virus. The spatial limitations of narrow public circulation spaces within informal settlements, which house over 1 billion people around the world, make it impossible for pedestrians to practice physical distancing (or social distancing). A flexible mathematical method, the Cluster Lane Method, is proposed for turning a planar circulation network of any size or complexity into a network of unidirectional lanes. This makes physical distancing possible in narrow circulation spaces by limiting face-to-face interactions. The opportunities and challenges are discussed for the implementation of this cost-efficient, low-tech solution. New notions and theorems are introduced for oriented graphs in graph theory. PRACTICE RELEVANCE A new approach based on graph theory is used to address the problem of COVID-19 contagion in the narrow public circulation networks of informal settlements. The Cluster Lane Method shows how to convert a planar circulation network of any size or complexity into a network of unidirectional lanes. This makes physical distancing possible in narrow circulation spaces by limiting face-to-face interactions between pedestrians. By involving the inhabitants of the informal settlement throughout the process, more adequate orientations of the lanes can be found.