Fuel tanks are part of the fuel supply. They are used to store and transport fuels during the operation of combustion engines. For safety, tanks are installed at a safe distance from the engine and outside the crumple zones, prefered in front of the rear axle, usually between the rear seats and the trunk. Pressure-resistant fuel tanks consist of steel sheets with corrosion-resistant inner and outer coating or impact-resistant plastic (polyethylene) and are not electrically conductive. The plastic fuel tanks produced by the extrusion blow-molding process are being adapted to the given room conditions and enable a weight reduction compared to traditional models made of steel sheets. Automobile fuel tanks are designed for distances between 400 and 700 km, filling speeds of 50 liters per minute are typical. Fuel tanks, which are installed on the right side of the vehicle as standard, are equipped with filler necks, filler tubes, overflow lines or rather venting pipes. Fuel pumps and rotary potentiometers with floats for the fuel gauge are installed directly at or inside the fuel tank, depending on the model. Fuel tanks are used in passenger cars, commercial vehicles and motorcycles.