Determination and modelling of CO2 emissions from motor vehicle traffic

© Ralf Gosch / Fotolia

The aim of the present research project was to develop a new method to determine and model the real fuel consumption and CO₂ emissions of passenger cars and light commercial vehicles in the HBEFA and TREMOD models both for past years and for the future. Another objective was to update the emissions inventory in TREMOD, taking into account the differences between the calculated energy consumption and the sales figures of the energy statistics.

In order to determine the discrepancy between official and real consumption values of European passenger cars, twelve data sources were considered. The results of the evaluation were the basis for the methodology development and modelling of the real consumption values with the PHEM model, which provides the basis for the HBEFA.

Finally, the new methodology and the updated consumption values were transferred to HBEFA and the total energy consumption of road traffic in Germany was recalculated with TREMOD. The energy consumption of domestic traffic calculated with TREMOD is higher than the fuel sold in Germany. Based on available findings from various studies, this difference can mainly be explained by differences in refuelling ("grey imports") between Germany and its neighbouring countries, although the uncertainties are high and require in-depth consideration.