Globally, different countries have different requirements for the size of semi-trailers. Understanding the size of semi-trailers is directly related to the legality of a company’s transportation, operational safety, transportation efficiency, and economic benefits.The following provides a detailed introduction to the main dimensions and standard specifications of semi-trailers, as well as the key considerations to understand before purchasing.
Understanding the Importance of Semi Trailer Dimensions
| Focus dimension | The main objective |
| Height | Make sure to cross the bridges and tunnels to avoid damaging the infrastructure. |
| Length | Determine the turning flexibility to avoid affecting the route planning. |
| Width | Make sure to drive in the designated lane and avoid excessive width penalties. |
| Internal volume | Improve the efficiency of single-trip transportation and increase revenue. |
Size of the Flatbed Trailer
The dimensions of flatbed trailers are usually defined according to the specific type of goods being transported. For example, the size requirements for flatbed trailers are completely different for transporting 20-foot, 40-foot, and 45-foot containers. It is important to communicate the container dimensions in advance so that an engineer can provide you with a design plan.
| Region | Length requirements | Width requirement | Cargo deck height requirements |
| China (GB1589-2016) | 13.0m – 13.75m | 2.55m | 1.4m – 1.5m |
| United States (DOT Standard) | 48ft – 53ft (14.6m – 16.1m) | 2.6m | 1.5m |
| European Union (EU) | 13.6m | 2.55m | 1.25m – 1.5m |
Lowbed Trailer Size
Total Length:Standard Lowboy trailers typically range from 13 to 13.75 meters in length. However, some specialized lowbed trailers can be extended to 20 or 30 meters using mechanical mechanisms to transport extra-long cargo.
Effective load-bearing surface length: refers to the flat area from the back of the gooseneck to the front of the wheelset. The effective load-bearing surface of a standard 13.75-meter vehicle is typically between 8.5 meters and 11 meters.
Width: Standard width of lowbed trailer: 2.55 meters or 3.0 meters. An extended design is available to accommodate extra-wide machinery; each side can be increased by 250mm when unfolded, bringing the total width to 3.5 meters.
Height – (Core parameter of lowbed trailer): The cargo surface height is typically between 0.85 meters and 1.2 meters.
The Size of the Fuel Tanker Trailer
The dimensions of an fuel tanker trailer directly determine its volume and driving safety. Since it transports liquid cargo, the size design must not only comply with road regulations but also consider the stability of the liquid’s center of gravity.
| Load capacity volume (liters) | Standard length(mm) | Standard width (mm) | Standard height (mm) |
| 30,000L | 9,500 | 2,500 | 3,600 |
| 40,000L | 10,500 | 2,500 | 3,700 |
| 50,000L | 11,500 | 2,500 | 3,750 |
| 50,000L-60,000L | 12,500 – 13,000 | 2,500 | 3,850 |









