Describing/Modelling the Dynamics of Pedestrian Behaviour: From the Role of Ambiance to a Hypothesis for a Physical Model

Let us look a little closely at the movement of people in public space. What do we see if we follow their paths, the relations played out among them, the areas occupied or left empty and, more importantly, the dynamics of these constant variations and adjustments? In designing public space, it is increasingly important to look at potential movement. This is the case whether considering the quality and diversity of itineraries (e.g. through parks, museums, stadiums, squares) or for the ease with which the public can get in to or out of a given place (e.g. shopping centres and railway stations). We must therefore seek to understand both the individual and collective dynamics involved here and bring to bear analysis and design tools that take them into account. Pedestrian behaviour in public space is a vast subject of research, involving numerous disciplines. This article will address it from the point of view of path making. The approach developed here highlights the role played by architectural and urban surroundings (Jean-François Augoyard 1979) in pedestrian dynamics, as situations of sensory interaction, which we experience according to a network-actor system (Bruno Latour, 2006). The actor may be a physical person, a group of persons, a moveable or fixed built object or semiographic features within the space, sensory elements of the environment such as a particular light, a zone or source of heat or coolness, soothing or stress-inducing sounds, and so on. We will first present the adaptation of a method of observation in situ (recurrent observation, (Pascal Amphoux, 2001), then describe experiments with a numerical relational model. This is the physical model developed by ACROE, which generates dynamics using the descriptors and operators of Newtonian physics (the force concept and the principle of action-reaction). The initial subject of study is an element of public architecture that is particularly dynamic, namely the automatic double doors at the entrance to a shopping centre. Since this first study (Tixier, 2000 ), numerous applications of this model have been developed and have enabled an approach to the whole of urban configurations having to do with public space to take place with a view to analysing existing spaces and investigating spatial design. This is covered in the third section of this article