Socio-economic stress in relation to car travel needs and transport alternatives : what is the contribution of energy costs ?

Fuel poverty and vulnerability have emerged as distinct concepts, respectively to characterize current household's inability to achieve their energy needs at reasonable cost with respect to their resources, and socio-economic risks associated with rising fuel prices. In the field of transport, they can manifest under the forms of either budgetary stress or travel restrictions, none of which is directly observable, but can be revealed through the estimation of car travel needs, while also accounting for transport alternatives. In this research, we resort to a Tobit model of daily car travel needs to reproduce the annual required car mileage distribution among French households through a Monte-Carlo simulation, which allows us to estimate the frequency of travel restrictions, along with degrees of related budgetary stress among households. Our results point out the contribution of rising car travel needs to the increasing frequency of travel restrictions, although public transportation alternatives allow to mitigate their severeness, especially in large cities. The variable adequacy of alternative transport supply across residential areas tends to reinforce the advantage of high-income groups through their ability to locate in central, well-desserved areas, thus contributing to reduce their vulnerability. By contrast, situations of transport-related socio-economic stress are found mostly among the poor and the lower middle class. The contribution of energy costs to transport-related socio-economic stress is modest in general, but more significant among low-income households and residents of low-density areas, in particular in small to medium urban areas and the rural space.