A bottom-up study on the relationships between transportation expenditures and socio-demographic variables: Evidences from the Italian case study

A precise understanding of the relationships between the household characteristics and the transportation expenditures is of paramount importance to support bottom-up policies, aiming at defining decarbonisation pathways keeping into account the household budget constraints. Despite the considerable amount of research activities carried out during the last decades, an agreement regarding the factors influencing the transportation expenditures is far from being reached. This paper contributes to the present-day discussion, focusing on the Italian case study, by analyzing the relationships between the private, public and total transportation expenditure and the socio-demographic and geographical dimensions. The impact that the household characteristics have on the transportation expenditures have been explored by coupling (a) the ordinary least squares method, to determine the relationship between the variables, (b) the variance inflation factor, to check for multicollinearity issues, (c) the least absolute shrinkage and selection operator, to select variable. Subsequently, a segmentation of the Italian households is proposed, by using a segmentation-tree approach and the outcomes of the previous analysis. It is found that the geographic area (in terms of the macro-scale as well as the micro-scale geographic locations) as well as income-related variables are likely to be factors influencing the transportation expenditures. These observations may serve as bottom-layer for the forthcoming studies regarding decarbonisation of the transportation sector, considering also the household budget constraints