Multilevel Pedestrian movement: does visibility make any difference?

Abstract

Hong Kong’s urban built environment is characterized by high-rise compact urban form with vertical distribution of land use accessed through multilevel spatial structure. In the large mixed use urban complexes developed around the high capacity mass transit system, the multilevel spatial structure (MSS) leads to various types of movement spaces like square, atrium, corridor, podium, footbridges, sub-ways. This variety of spatial expression connected by vertical transitional space induces varied pattern of movement that in turn has implications for the extreme high-density urban living. During the initial days of Hong Kong’s urban development this MSS was designed mainly to separate the pedestrian movement from the vehicular traffic. But in course of time it has evolved as an indispensable part of the compact built environment. Using visibility graph analysis this study investigates the visual dimension of a large multilevel complex in Hong Kong. The aim is to understand the relationship between the visual accessibility and pedestrian movement of such complex spatial system. Owing to the prominence of urban design parameters like the mass transit railway (MTR), level variation, and vertical transitional spaces which are characteristic to such compact development, the study develops an integrated model that includes the isovist properties and some other variables to take into account the effects of the key urban design parameters in a single statistical model. Preliminary finding of the study reveals, notwithstanding the strong influence of the urban design parameters, visibility of multilevel spaces seems to have significant effects on the observed patterns of movement. The study suggests that the visual accessibility of the multilevel public circulation spaces may prove to be an important spatial quality to the description of pedestrian movement in other highly complex but comparable built environment.