Introducing social contacts into the node-place model: A case study of Hong Kong

Abstract

The node-place model epitomizes metro stations as nodes in a city's transportation network and station areas as places accommodating activities in the city. According to this model, stations and station areas with balanced node and place contents/values contribute to harmony among human interactions, land uses, and (public) transportation services. The harmony is indispensable for civic engagement, quality of life, and well-being of urbanites. Most of the existing studies on the model, however, focus on transportation services and land uses. Little has been done on whether and how social contacts play an essential role in such harmony and are associated with node-place values. In this article, we therefore measure social contact in a city and introduce social contact as a third aspect to the node-place model. In particular, we introduce a method to identify group travel activities in the metro system, as a proxy for social contact, by using smartcard swipe records from Hong Kong's metro system in 2020. We then define and calculate place values, node values, and the intensity and density of social contacts by metro station or station area. We find that some stations with balanced and even stressed node-place values would have relatively low social contacts. The conventional node-place framework is not capable of capturing and evaluating realized social contacts of a metro station area. There exists a gap between realization of social contacts and the interaction potential facilitated by both node and place values of stations. Our new model allows us to better categorize different metro station areas according to their respective realized social contacts.