Low plate semi-trailer is a type of vehicle commonly used in the domestic transportation industry, such as 17.5 large plate car. Strictly speaking, it belongs to low plate trailer. In accordance with the requirements of regulations, low plate semi-trailer is specially used for large and not disassembled heavy goods transportation, but in actual transportation, some owners tend to use it for general goods transportation such as zero-load, green pass, and even "what goods can pull, what money can earn", so that the owners of those who are in compliance to run transportation love and hate. According to the notice issued by the Ministry of Industry and Information Technology in 2007, the announcement of 17.5 large plates has been cancelled and cannot be produced or licensed again. According to the regulations, the last batch of 17.5 large plates licensed will also reach the scrap point now, or will not be able to drive on the road. Top semi trailer manufacturers claimed Mountain rain has not arrived, the wind has been full floor, although the old model has not quit, the current model has taken over, such as the current "super" word temporary car or 13.75 plate car. According to the technical specification given by the Ministry of Transport in March 2020, the longest low plate semi-trailer can be 13.75m, that is to say, the 13.75m large plate may become a compliance "substitute" for the 17.5 large plate. In terms of quality parameters, the original version of the standard requires three axis low plate quality ≤10t, the current requirements are ≥42t, five axis ≥55t. Compared with other types of semitrailers, low plate semitrailers can load up to 140 square meters, considerably higher than the volume of standard van semitrailers. But it should be noted that 13.75 large plate car can only be used for the transportation of large and not disassemble the goods. That is to say, it is illegal for general goods transportation, once the relevant departments improve the governance efforts, such as "one penalty four", numerous illegal vehicles or will be idle down. It is suggested that the owners should follow the law of industry development, compliance transportation can be more conducive to the long-term development of the freight market. Under normal circumstances, the structure of low plate semi-trailer adopts a concave beam frame, that is, the front section is gooseneck, the middle section is cargo platform, the rear section is wheel frame, and there is no fence plate around. When loading and unloading, move the mechanical equipment from the rear wheel frame or remove the wheel, and then secure the mechanical equipment to the semi-trailer. This kind of gooseneck type flat car can effectively reduce the center of gravity, which is convenient for the loading and unloading of goods, and can improve the stability of the vehicle and the stability of the road on the height limit. It should be noted that the gooseneck section is not allowed to carry cargo. In addition to this gooseneck type of flat car, numerous owners have seen the following picture of a flat body girder, no gooseneck: In fact, this model does not belong to the low plate semi-trailer, simply not installed and installed ordinary semi-trailer, compared with the Gooseneck low plate, its center of gravity is higher, the load is smaller, the same configuration can be about 2000 yuan cheaper. Due to the particularity of low plate semi-trailer in the application field, its accessories are also different from ordinary semi-trailer.