It depends on the speed and size of the vehicle. The shell of the Hussardes has been studied aerodynamically in order to present a very low Cx (drag coefficient). On the road at 80 km/h, the additional consumption is not noticeable. On the motorway, depending on the size of the vehicle, overconsumption varies from almost nothing (large vehicle) to 20% (small vehicle). Speed has a significant impact so we recommend reducing it to limit consumption.