The pedestrian speed-density relation: modelling and application.

The relation between density and velocity of pedestrian movement has so far mainly been analysed using an empirical approach and fundamental relations found from the fitting of experimental measurements of the main quantities. The present study proposes a phenomenological model that is able to distinguish and take into account various factors that can affect the density-velocity relation by means of the induced microscopic walking phenomena. In particular, three factors are retained: the geographic area; the travel purpose; the effect of the lateral vibrations of the platform on which pedestrians walk, in view of the use of the fundamental diagrams within a crowd-structure interaction model applied to lively footbridges. The main features of the phenomenological model are then applied to a non-linear law found in literature and herein revisited in a more general form. The latter is finally used within a crowd-structure interaction model, which is applied to the T-bridge in Japan, in order to perform a sensitivity study of the deck response to different travel purposes.