The fuel tank semi-trailer is a towed heavy-duty vehicle designed for bulk transportation of gasoline, diesel, aviation fuel, and other liquid petroleum products. It features a cylindrical or elliptical tank body made of carbon steel, aluminum alloy, or stainless steel, typically divided into multiple compartments for carrying different fuel types. Mounted on a multi-axle chassis (2 to 4 axles or more), it offers capacities ranging from 20,000 to 50,000 liters or more. Equipped with essential safety features such as anti-rollover devices, emergency valves, grounding reels, and fire extinguishers, it is widely used for long-distance fuel delivery to gas stations, airports, and industrial facilities.