An articulated vehicle can typically make sharper turns than a rigid vehicle of a similar length. To manage this, these vehicles are designed with a pivot, which can allow them to bend from side to side. An articulated vehicle may be one cohesive unit, such as a bus, or a two-part unit, such as a truck and trailer. In the latter case, the pivot typically consists of the ball or fifth-wheel hitch that connects the trailer to the truck. Articulated vehicles are often used in both heavy construction and military applications.
Articulated buses are a common design that can allow long buses to navigate the sharp corners present in cities. Where a rigid bus of equal length might be unable to turn certain corners, adding an articulation can essentially allow the vehicle to bend around the corner. The articulation in this case typically includes a large joint in the chassis and an accordion-like wall and roof construction. Certain very long buses may even include a double articulation.
Trains have historically also been a kind of articulated vehicle in one way or another. Some train cars have utilized an articulated type of connection, wherein one car shares a common set of wheels with the car in front of or behind it. Since trains travel on tracks and don't have to negotiate especially tight corners, this design imparted other benefits. By sharing wheels between cars, the weight of the entire train could be reduced. This may have also allowed the trains to travel more quickly.
The articulated vehicle may also be used by military units and the heavy construction industry to improve a vehicle's turning radius. This can be convenient in construction zones, which might present tight working quarters. In military applications, the ability to make tight turns with large vehicles can be beneficial when traversing rough or unfriendly terrain.
A form of articulated vehicle that isn't one single unit is the semi-trailer. These vehicles consist of a heavy truck and one or more trailers. The trailers that are towed typically lack a front axle; instead, the trailer is mounted to the truck via a fifth-wheel hitch. This forms the pivot seen in all articulated vehicles, and in some cases a second or even third trailer may be connected to the rear of the first. In places such as the United Kingdom (UK), the semi-trailer may be known as an articulated lorry.
