Conceptual modelling of the interaction between transportation, land use and the environment as a tool for selecting sustainability indicators of urban mobility.

There is an internationally shared agreement on the use of indicators for evaluating the sustainability of the observed patterns of urban development. The most commonly used framework to organise and select such indicators is the Pressures-State-Responses scheme. First proposed by the OECD to organise environmental indicators, its inadequacy is increasingly evident. The weaknesses of the conceptual frameworks currently used in urban sustainability analysis induced us to develop a more coherent theoretical framework in the form of a systemic scheme. The new scheme combines the causal approach of the Pressures-State-Responses model and the focus on urban sustainability issues of the extended urban metabolism model by Newman and Kenworthy. In this paper, the new scheme was used to derive a systemic framework for the assessment of the sustainability of urban mobility. First, we adapted the general scheme to the analysis of urban mobility. Successively, using the cognitive mapping software Decision Explorer, we further developed this scheme to obtain a more disaggregated conceptual model. A selection table could be derived for every element of the model to guide the selection of pertinent indicators based on the systemic links of the element. We could thus define a set of some sixty system indicators to be used in the assessment of the sustainability of urban mobility. The selected set of indicators reflects the causal links between phenomena and can monitor the attainment of sustainability objectives for the urban mobility system. All indicators allow geographical comparison and integrate the role played by different urban actors and modes of transportation. This work has been carried out within the first year of a joint PhD research program at the University of Nice-Sophia Antipolis and at the Polytechnic of Milan.