The research study investigates fuel consumption of a passenger car depending on aerodynamic resistance and related aspects. Introduction and next chapter describe all the resistance kinds affecting a passenger car while in-motion. Subsequent part outlines particular aspects such as aerodynamic resistance, aerodynamic resistance coefficient, car velocity and air temperature in terms of their effect on fuel consumption of selected passenger car. The most important chapter compares fuel consumption while a passenger car is in-motion on an expressway with closed and open windows with fuel consumption on a first class road infrastructure.