Does accessibility shape land use? Or, does land use shape accessibility? Or do both?

The theme of accessibility leads us into the gap between its well-established notion in territorial modelling and the meaning it constantly assumes in the common speaking. Aiming at bridging the gap, the use of configurational analysis for the solution of problems of material accessibility is here proposed: the notion of accessibility the configurational theory implicitly conveys, as a function of the configuration of urban spaces, does in fact appear a useful conceptual link between those mentioned so far. Its use can hence allow a quantitative approach to the theme of the improvement of urban accessibility, so as to overcome the limits of subjective and discretionary evaluations. With such purpose, this paper proposes the integration of the classic notion of interactional accessibility (that is the generalized one) with the configurational accessibility (that is the spatial, or pure, accessibility) into a single operational method, aimed at supporting and orientating the strategies for enhancing the material accessibility of urban spaces. The proposed method can hence be assumed as a support tool for the working out of the Italian PEBAs (Piani per l’Eliminazione delle Barriere Architettoniche), in that it allows to calibrate the demand for accessibility each urban space does actually claim, with reference to the located activities (their position, their consistency) and to their integration in the grid as well. The method is here applied to several case studies. And the results it provides appear so interesting as to encourage further studies.