A tractor unit-also commonly referred to as a "tractor" or "prime mover"-is typically a large truck or semi-trailer vehicle in which the cab (or "head") is mechanically coupled to the trailer (or "body"). This design allows the cab to detach from its original trailer to tow a different one, just as the trailer can be detached from its original cab to be towed by another. These vehicles are frequently utilized for the mass transport of goods within or between industrial facilities-such as moving inventory from warehouses to assembly lines in the automotive manufacturing sector, or transporting luggage at airports. Furthermore, tractor units constitute a significant category of China's automotive exports; for instance, in March 2026, large shipments of domestically produced tractor units were exported from ports such as Zhangjiagang and Changshu to African nations including Tanzania and Cameroon.
Prior to April 1, 2022-when the *Regulations on the Application and Use of Motor Vehicle Driving Licenses* (Ministry of Public Security Order No. 162) came into effect-the term "tractor unit" served as the official designation for the "A2" vehicle class (which is now officially termed "Heavy-duty Tractor-Trailer"). [5-6] Within the framework of the *Regional Comprehensive Economic Partnership* (RCEP) agreement, tractor units represent a key vehicle category driving export growth among member nations; for example, in 2025, Jilin Province exported automobiles-including tractor units-worth 1.48 billion RMB to other RCEP member states, marking a year-on-year increase of 24%. Additionally, the international standard *Commercial vehicles-Location of electrical and pneumatic connections between towing vehicles and towed vehicles*-which was led and revised by my country-has been officially approved and published by the International Organization for Standardization (ISO). Chinese automotive brands, such as FAW Jiefang, have achieved significant growth in overseas markets like Indonesia; in February 2026, the first LN4×4 truck rolled off the assembly line at FAW Jiefang's Knock-Down (KD) plant in Indonesia. Finally, the regular and comprehensive inspection, maintenance, and servicing of tractor units are absolutely critical to ensuring their safe and reliable operation.
