Trucks play an extremely important role in many countries since these vehicles carry much of the most varied and essential products such as clothing, water, food, and other goods. Many industries have huge fleets of trucks, which makes it necessary to reduce the cost of fuel consumption as it represents a large portion of the total cost of services rendered. But there is an obstacle known by air resistance, which is one of the biggest responsible for the fuel consumption. Also, the automotive industry aims for more economical cars not only for profit by reducing development costs and maybe a bigger market share, but also to meet government-established emissions requirements for the preservation of health and the environment, which are getting even stronger year by year. However, to help engineers with this challenge, it is now possible to know in advance the aerodynamic performance of vehicles thanks to the great advances in Computational Fluid Dynamics (CFD), such as turbulence models and calculation codes, and available computational resources. Therefore, MSC Software conducted this study using Cradle's CFD solutions in which comparisons were made between two designs, one basic and one with additional exterior parts to improve the aerodynamic performance of the same truck. Results demonstrated the reduction of drag coefficient and its positive impact on fuel consumption.