Modelling car-related socio-economic stress among French households : choice of indicators, contribution of energy costs, and impact of public transportation alternatives

This research displays a methodology to assess transport-related socio-economic stress, by simultaneously accounting for financial stress and travel restrictions among households. The cornerstone is a Tobit model of car travel needs, which is calibrated on French Household Travel Surveys, before using it to calculate the distribution of car travel needs through a Monte-Carlo simulation. The estimation of car travel needs allows us to estimate the frequency of car travel restrictions, indirectly revealing degrees of financial stress among households. These indicators are completed by an assessment of public transportation alternatives. Among our results, rising travel needs resulted in increasing the frequency of travel restrictions over the period 1994-2017, although their severeness is mitigated by public transportation alternatives, especially in large cities. The heterogeneity of supply reinforces the advantage of high-income groups through their ability to locate in central areas, allowing them to reduce their travel needs and decorrelate motility from the car. Transport-related socio-economic stress mostly concerns the lower half of the income distribution, corresponding to the poor and the lower middle class. In the end, we study the contribution of energy costs to these indicators, in a context characterized by recurrent social protests about fuel price rises.