(1) Semi-trailer
A semi-trailer is a trailer with an axle mounted behind the vehicle's center of gravity and equipped with a coupling device that transmits horizontal and vertical forces to the tractor. Generally speaking, the wheels of the semi-trailer are generally installed at the rear end of the carriage, and the front end of the carriage needs to be put on the saddle of the tractor when driving, and the tractor not only needs to provide the forward force of the carriage, but also needs to bear the weight of a part of the carriage. When disengaged from the tractor, the semi-trailer compartment cannot be balanced alone, and needs to be supported with the help of outriggers.
(2) Full trailer
Full trailer refers to the carriage load is completely borne by itself, and the tractor is connected by the hook, and the tractor only needs to provide a forward driving force to the trailer, and does not need to bear the weight of the carriage. Trailers are usually equipped with axles at the front and rear of the vehicle, so they can maintain balance on their own even when they are separated from the tractor.
(3) Mid-axle trailer
The axles of mid-axle trailers are often installed in the middle of the carriage, so they cannot be balanced independently when disengaged from the tractor, and they also need the strength of the trailer legs. Some owners feel that the central axle looks very similar to the full trailer, in fact, the difference is quite big, in addition to the fact that the balance can not be maintained independently, the connection between the compartment and the tractor, the connection position is also different, and the driving is slightly less difficult than the full trailer.
Whether it is a semi-trailer, a full trailer or a mid-axle trailer, you need to get an A2 license to drive on the road. A B2 licence allows you to drive a cargo vehicle, but you cannot drive a trailer. The permitted driving types of A2 driver's license mainly include tractors (including semi-trailers and full-trailers), medium-sized buses, large trucks, small manual transmission vehicles, small automatic transmission vehicles, low-speed trucks, three-wheeled vehicles and wheeled self-propelled mechanical vehicles.
