A fuel supply system for a road vehicle and having: a fuel tank, which is shaped like saddle due to the presence of a central saddle and delimits an inner volume divided into an upper area, which is located above the central saddle, and two lower areas, which are located under the upper area and are separated from one another by the central saddle; two low-pressure fuel pumps, which each suck from the bottom of a corresponding lower area; at least one high-pressure fuel pump, which receives fuel from both low-pressure fuel pumps; a level sensor arranged in the upper area and configured to measure a fuel level only in the upper area; and two level sensors, each arranged in a respective lower area and configured to measure a fuel level only in the respective lower area.