Fuel consumption and CO₂ emission are important drivers of automotive industry product evolution. In Europe, the manufacturers have the compromise to reduce their fleet consumption steadily and, in Brazil, a still voluntary but growing labeling program makes the vehicular energetic efficiency one of the main concerns during the concept phase. Although powertrain efficiency plays a decisive role, also vehicular parameters such as weight, aerodynamic, tires rolling resistance and electrical and mechanical loads have an important influence on fuel consumption and CO₂ emissions. The cost-benefit analysis of the modifications in these parameters needs to be performed in the early project stages, where prototypes are still not available. Therefore, the objective of this article is to summarize and compare the magnitude of influence of these parameters on the fuel consumption and CO₂ emission on the urban and highway cycles defined by the Brazilian standards NBR 6601 and NBR 7024 using a computational simulation tool and taking a small popular flexible fuel vehicle as the base of comparison.