The focus of the work is to carry out a study of the relative impact of the rolling resistance measurements on CO₂ emission and fuel consumption reduction for heavy-duty vehicles. For the purpose of the study, friction coefficients of the tires from tire test machine according to UN/ECE Regulation No 117 test procedure have been used. The rolling resistance coefficient has also been obtained from SAE J1263 and SAE J2263 procedure for coast-down determination on proving ground. The fuel consumption has been simulated and tested on the proving ground by following FIGE standard cycle and stabilized speed conditions. A simulation tool has been developed and validated by testing different rolling resistance coefficient tires, analyzing their effect on the fuel consumption. The analysis of the contribution of the tires to fuel consumption achieved on the test track has been correlated with the experimental results and those obtained from the simulation tool. Finally, the simulation tool has been used to predict the fuel consumption and CO₂ emissions that have been compared with the experimental results. The sensitivity analysis provided by the simulation tool allows a prediction of the potential fuel consumption savings in the different sub-systems. From the different possible subsystems, the rolling resistance improvement option has been chosen because it has shown a relatively high influence on fuel consumption savings without reducing other vehicle performances or significantly increasing costs and timing. An accurate measurement methodology considering the main variables that influence rolling resistance has been implemented in order to obtain consistent results. This study gives guidelines for fuel consumption savings process for heavy-duty vehicles, but further work is required to extend the methodology to other cases. Through this work, a better understanding of the effect of accurate rolling resistance measurements on the energy efficiency and fuel consumption prediction for heavy-duty vehicles can be achieved. Also a relation has been achieved between the rolling resistance reduction and fuel consumption reduction potential for the heavy-duty vehicle under study. The effect of accurate rolling resistance measurements has been evaluated yielding the necessary guidelines on the fuel consumption prediction for heavy-duty vehicles. Finally, the economic and emission impact of the tires with low rolling resistance coefficient characteristics used in the study has been established.