puoliperävaunu

Puoliperävaunu, also known as a semi-trailer, is a type of trailer that is used in conjunction with a tractor unit to form a semi-trailer truck. Unlike a full trailer, a semi-trailer does not have its own front axle; instead, a portion of its weight is borne by the tractor unit. This is achieved through a coupling device called a fifth wheel, located on the rear of the tractor unit.

The design of a puoliperävaunu allows for a significant portion of the cargo load to be transferred to the towing vehicle, which simplifies steering and maneuvering compared to a full trailer. This weight distribution also contributes to better stability, especially when loaded. Semi-trailers come in various configurations and lengths, each designed for specific types of cargo and transport needs. Common types include box trailers for general goods, flatbeds for oversized or heavy items, and tankers for liquids or gases.

The tractor unit, which provides the motive power, is specifically designed to handle the load from the semi-trailer. The combination of a tractor unit and a semi-trailer is a prevalent mode of long-haul freight transportation worldwide due to its efficiency and capacity. The detachability of the semi-trailer also allows for quick trailer swaps, meaning a tractor unit can uncouple from one trailer and attach to another without extensive downtime. This flexibility is a key advantage in logistics operations.