The reduction of CO2 emission levels is one of the major concerns of the automotive industry.OEMs and suppliers are focused on the development of more efficient powertrain solutions and the improvement of vehicle running resistance.For this purpose,the main innovation is a methodology which enables enhanced integration of the expertise and testing capabilities in different engineering functional areas in order to obtain the vehicle running resistance contributions in an accurate,reliable and effec-tive way.The split-up of the contributions allows their individual impact in the energy consumption and the potential of CO2 reduction of the different possible vehicle improvements to be calculated.