Multidimensional inequalities in attributed passenger-transport CO2 across 21 EU member States in 2015

Passenger-transport decarbonisation raises distributional questions, but harmonised physical travel data by household group remain scarce. We attribute national mode-specific CO 2 totals from a bottom-up transport model to 60 household-consumption cells in each of 21 EU Member States in 2015. WILIAM cells combine five income quintiles, two settlement-density categories and six household compositions, constructed in LOCOMOTION by statistical matching and reconciliation to 2015 national accounts. This is an accounting attribution, not a direct measurement of group-specific travel activity or technical efficiency. Within each country–mode, attributed-emission ratios and Ginis reproduce the corresponding WILIAM consumption metrics by construction; multimodal totals instead weight modal consumption by distinct attribution intensities. The official-population-weighted resident mean for the covered 21-country sample is 1507 kg CO 2 /person/year. Across countries, the median total Q5/Q1 is 2.75, compared with 4.44 for air and 2.59 for private transport. Median grouped Ginis are 0.322 for air, 0.176 for private transport, 0.184 for rail and 0.082 for bus CO 2 attributed using road-passenger-service expenditure shares. A structured-scenario envelope gives a median national total Q5/Q1 of 1.57–4.76; it is not a confidence interval. Dense cells receive higher total and aviation attributions on average, whereas non-dense cells receive higher private attribution. The baseline identifies where transport CO 2 totals are attributed and formulates testable hypotheses about aviation concentration, car dependence, heterogeneous adjustment and public-transport pricing. Its policy contribution is diagnostic and hypothesis-generating: it specifies where credible incidence models need greater resolution and which price, accessibility, behavioural and compensation mechanisms they should test.