Freight can be of a wide range of types, weights sizes and uses, and may need to be hauled to party of the planet normal people never hear about or could imagine. There are many categories of freight which cannot be transported in typical box containers (the same type which are also transported on ships and aircraft).
Specialized loads are basically cargo which is impossible or very difficult to load onto some semi-trailers, box containers and rigid or small trucks. Usually this is mainly due to the size and / or weight of the container however it can depend upon the type of cargo.
Specialized truck and trailer combinations
Lowboy Trailer: This is a type of trailer hauled by a typical tractor. Its floor is set very low, closer to the ground than any other type of freight transportation vehicle and is used to haul heavy equipment such as bulldozers and cranes etc.
Car Carrying Trailer: This type of trailer is designed with a low double deck and to carry vehicles on two levels. The standard length of this type of semitrailer is doubled with the addition of the second deck and can carry up to ten average sedan cars. The cars are locked in place with clamps attached to the deck. This type of freight carrying trailer is usually used by car manufacturers to transport car frames and finished cars to showrooms and dealerships.
Car Carrier Truck with Central Axle Trailer
Drop-deck Trailers: These are trailers which have a drop-down deck. When not attached to a tractor-truck, the deck drops down to allow loading and unloading of heavy freight. Some common flat-bed trailers have drop-decks.
Side-Lifter: This type of trailer has hydraulic cranes mounted at each end of the trailer chassis and allow for the loading or unloading of heave goods, construction equipment such as pipes or rebar, without the need for cranes of fork-lifts.
Side Lifter Container Trailer
Double-decker: this is a type of box semi-trailer with a fixed, floating or hinged second deck on top of the first. This type of trailer is used to carry extra load of palletized goods with at least more than 40% capacity, and is very flexible as it can be divided into sections to carry different types of cargo.
Ballast-tractors: these are the largest types of heavy haulage trucks and are capable of both pulling and pushing extremely heavy and very large cargo such as movable machinery and very large loads of regular cargo etc. It's most common use is as a showman vehicle, capable of transporting amusement-park rides and carnival rides.