Road freight transport presents different types of trucks available according to the type of goods carried. Here is a full overview of the several vehicle structures:
- Rigid Vehicles: a chassis-cab, literally a chassis with a driver’s cab fitted at the front, and another party constructs the load-bearing bodywork that is fitted to the rear of the cab. Rigid vehicles have either two or three axles. Commercial trucks with two axles have a payload carrying capacity up to eight tons, and those with three axles have a payload-carrying capacity of up to 15 tons
- Articulated vehicles: they are made up with two solid structures that bend in the middle. There are two different types: Trailers and road trains.
- Trailers integrate two different units: a cab and a towed trailer (semi-trailer), both independent and articulated. The cab is the prime mover that carries the semi-trailer but does not carry any loads itself as goods are transported inside the towed trailer.
- Road trains: A multi-combination vehicle including both structures above mentioned and hauling more different trailers. This can be a prime mover hauling more than one trailer or a rigid body truck hauling two trailers.
It is crucial to understand all different characteristics of road freight vehicles first before learning about the main types trucks according to type of goods carried.
Types of Trucks
- Flatbed truck: includes a load floor and removable side rails and a bulkhead in front to protect the tractor in the event of a load shift. Can haul almost anything (heavy loads, containers, bulks).
- Vehicles with truck tarps: It is the most common truck used for all types of loads generally. As tarps can cover any part of the body truck (roof, sides or door). It is quite flexible when goods seem to be difficult to load.
- Refrigerated truck bodies: Used for transport of goods (generally food) that needs temperature monitoring. An integrated engine keeps the solid structure cool and at a right temperature.
- Tanker trucks: liquids, chemicals and gases are transported and stored during a certain period of time according to their specific needs. Usually they carry petrol, oil, LP gas and other chemicals registered by ADR regulation.
- Box trucks: are rigid and straight trucks used for average transport of goods like courier and main delivery services. However goods have to be loaded up and down through the back doors of the vehicle.
- Transportation of certain special types of goods: For example trucks that transport animals alive (cage trucks) or other vehicles (car carriers).
Road freight vehicles are used for the carriage of bulk freight in cases where rail transport is not the suitable mode of conveyance carriage of bulk freight in cases where rail transport is not the suitable mode of conveyance
Dry bulk trailers (hopper trailers) are used to transport free-flowing dry bulk commodities. The hopper trailer is distinguished from an open trailer with a solid flat floor in that it has opening hatches on the underside or on the sides to discharge its load. Hopper trailers are loaded from the top and unloaded by gravity through funnel-shaped receptacles (hoppers) on the undercarriage of the vehicle. There are two main types of hopper trailers: open and covered.
Open hopper trailers are used to transport commodities that may get wet and dry out without harmful effects, mostly mining products. Covered hopper trailers have sliding roofs for freight that must be protected from the elements, such as grain, sugar and fertilizer.
Tankers are suitable for the carriage of a wide variety of bulk liquids, gas and powders/pellets in tanks integrated into the vehicle. Commodity loading is performed pneumatically or by pouring commodities from the top.
Unloading is done in several ways
- pneumatically from the top of the tank (such as the various types of acid, gas and volatile substances)
- pneumatically from the bottom of the tank (such as slurrified substances and powderised or pelletised material
- decanted from the bottom (such as liquids that thicken when cooled off (such as oil, tallow, tar/bitumen and creosote) which are first heated with in-vehicle fitted heaters)
- drained or poured (such as liquids that can flow freely from the bottom of the tank without the necessity for pneumatic pumping and pre-heating, e.g. refined petroleum products and most potable liquids).
Various freight types that are not suited for containerisation or bulk carriage are transported in special vehicles custom-designed for the freight. The most prominent of these are
- Moisture-susceptible goods that have to be transported in fully enclosed vehicles, commonly known as “vans”. Vans are designed to carry break-bulk, mostly boxed, crated, bagged, wrapped and palletised freight of all kinds. Common commodities transported are paper products, wooden products (e.g. furniture), canned goods and food products. The payload is typically made up of less-than-truck-load and less-than- container-load shipments. Vans are often equipped with various interior loading devices, for example belt rails and moveable bulkheads, to secure loads.
- Goods that require certain temperatures, ranging between freezing and normal room temperature, during transportation can be carried in refrigerated vans; however, refrigerated containers are becoming more dominant. Goods types that require refrigerated carriages are perishable items such as vegetables, fruit, juices, dairy products, red meat, poultry and fish. Some shipments of fruit and vegetables require only insulated and ventilated enclosure to retard the ripening process. Meat vans are equipped with specialised rails for animal carcasses. Dairy and poultry products require specialised interior racks to ensure cooled air circulation.
- Heavy items that are not subject to damage by the elements (e.g. marble and granite blocks and uncontainerised indivisible oversized items) are carried on flatbed trailers.
- Uncontainerised oversized items, for example transformers, agricultural equipment and machinery, that would exceed height restrictions if carried on open wagons and flatbed trailers.
- Metal objects, for example, steel ingots, metal sheets, coiled steel, pipes, bundled and compressed scrap, and palletised hardware and building material, are transported in standard open trailers.
- General goods that are packed in bags can be carried in open trailers with high sides. Weather-sensitive goods can be transported in waterproof bags, otherwise the trailers can be covered with tarpaulins if necessary.
- Long items, such as logs, poles and steel rods and rails, and baled goods can be carried on long open trucks and trailers equipped with stanchions on the sides.
- Light road vehicles, mostly motorcars, station-wagons, panel vans, minibuses and light trucks, are transported in open or closed motorcar carriers. After the vehicles are driven on, they are secured/fastened during transit and then driven off the trailer at the destination, using a fold-up ramp attached to the trailer.
Container freight transport
It is rapidly gaining market share over the traditional break-bulk method of carriage. Semi-finished and finished items that can fit in standard containers have become the dominant type of non-bulk haulage. Transport operators internationally use standard-size containers that are 6,0 m or 12,0 m long, 2,4 m wide and 2,4 m or 2,6 m high, making them suitable for intermodal transport. Various container types are available to meet the needs of the following freight types and packages
- General-purpose containers for boxes, cases, wrapped pallets, bags, drums, etc.
- High cube containers for bulk commodities and items taller than 2,4 metres
- Open-top containers for tall indivisible items exceeding a height of 2,6 metres
- Flat-rack containers for out-of-gauge cargo
- Refrigerated containers for perishable goods
- Ventilated containers for products requiring ventilation (e.g. to retard the ripening of fresh produce)
- Tank containers for liquids and gas
- Insulated containers to avoid environmental contamination or impact
- Platform containers for barrels, drums, cable spools, machinery and processed timber
- Collapsible containers – for lower cost of returning containers to owners
Primary and Secondary
Road freight transport operations can be broken down into two main types. These are primary transport and secondary transport.
The primary transport element is the movement of full loads on large vehicles with a single delivery point. Primary transport is all about moving the product at minimum cost, which generally involves using as large a vehicle as possible and making sure that the vehicle is filled to capacity. Vehicles are operated for as long as possible, sometimes on a 24-hour, three-shift basis, to maximize vehicle time utilization. Return loads is important in order to achieve the maximum load utilization of the vehicle.
The secondary transport element is the movement of loads on smaller delivery vehicles. It usually involves direct contact with the customer or end user. Customer service is the major criterion and not cost reduction. Accurate scheduling of secondary vehicles very important. Service is usually critical. Specialist vehicles may be used for secondary delivery.
Types of trailers and semitrailers
There are many types of trailers and semitrailers commonly used internationally, which are
- Vans are designed for the transportation of moisture-susceptible goods and therefore are fully enclosed, with sliding or roll-up doors on one or both sides, swing or roll-up doors at the rear side, and a fixed roof. Vans are designed to carry break-bulk, mostly boxed, crated, bagged and palletised freight of all kinds. The payload is typically made up of less-than-truck-load shipments. Vans are loaded and unloaded from the side or the rear. Freight handling is conducted either completely or partially manually using wheeled ramps and maneuverable belt or roller-bed conveyors, or through the use of forklift trucks.
- A refrigerated van is completely enclosed and insulated, and has mechanical cooling equipment or a cooling medium, such as carbon dioxide, in order to carry perishable freight at desired temperatures. Refrigerated vans are loaded and unloaded from the side (in which case the doors are also insulated), or through the rear. Freight handling is conducted either completely or partially manually using wheeled ramps and maneuverable roller-bed conveyors, or through the use of forklift trucks.
- Container carriers consist of an open, fully accessible solid flat or a spine (skeletal) deck that supports the container. Container carriers are loaded from the side or the top.
- Flatbed trailers are designed to carry oversize freight that is too big to fit into standard containers, although standard and high-cube containers are often transported on flatbed trailers. Flatbed trailers are loaded from the side or the top.
- Lowbed semitrailers (colloquially called gooseneck trailers) are designed to carry high-cube containers and oversize freight that cannot fit into standard containers, on a depressed flat payload section behind the drawbar section that is lower than that of a traditional container and flatbed trailer. Lowbed semitrailers are loaded from the side or the top, and sometimes wheeled machinery (especially chain-wheeled construction machinery) is driven on and off using fold-up ramps at the departure and destination points, while being secured/fastened during transit.
- Tankers are suitable for the carriage of a wide variety of bulk liquids, gas and powders/pellets in tanks integrated into the vehicle. Commodity loading is performed pneumatically or by pouring commodities from the top. Unloading is done in several ways: (a) pneumatically from the top of the tank (such as the various types of acid, gas and volatile substances); (b) pneumatically from the bottom of the tank (such as slurrified substances and powderised or pelletised material; (c) decanted from the bottom (such as liquids that thicken when cooled off (such as oil, tallow, tar/bitumen and creosote) which are first heated with in-vehicle fitted heaters); and (d) drained or poured (such as liquids that can flow freely from the bottom of the tank without the necessity for pneumatic pumping and pre-heating, e.g. refined petroleum products and most potable liquids).
- Livestock trailers are designed to transport all kinds of livestock, mostly cattle, sheep, goats and hogs. These vehicles have ventilation openings on the sides; doors on the sides and rear appropriately designed for the kind of livestock to be transported; and ramps to herd livestock into and out of the vehicles and between decks. The floors are textured and the side walls are often cushioned to minimise livestock slipping or sustaining injuries. Conventional livestock trailers are not suitable for the conveyance of horses and poultry.
- Dry bulk trailers (hopper trailers) are used to transport free-flowing dry bulk commodities. The hopper trailer is distinguished from an open trailer with a solid flat floor in that it has opening hatches on the underside or on the sides to discharge its load. Hopper wagons are loaded from the top and unloaded by gravity through funnel-shaped receptacles (hoppers) on the undercarriage of the vehicle. There are two main types of hopper trailers: open and covered. Open hopper trailers are used to transport commodities that may get wet and dry out without harmful effects, mostly mining products. Covered hopper trailers have sliding roofs for freight that must be protected from the elements, such as grain, sugar and fertiliser.
- Furniture vans (pantechnicons) are specifically designed to carry bulky but relatively light freight, i.e. large freight items of which the mass-to-volume ratio is low. Pantechnicons (also referred to as deep drop vans – the floor being lowered to facilitate easy loading and to create voluminous payload capacity) are used to convey furniture, for household removals, and for big fragile items that need bulky packaging.
- Motorcar carriers are enclosed or partly enclosed trailers designed to carry light road vehicles (not only motorcars). Motorcar trailers feature an adjustable deck that can be reconfigured as bi-level to accommodate different vehicle shapes and sizes. The vehicles are driven on at the departure terminal, secured/fastened during transit and driven off the trailer at the destination using ramps.
- Side stanchion trailers feature stanchions on the sides between which freight can be secured. Common goods items carried include mainly logs, poles, masts, steel rods, steel rails and prefabricated long building materials (e.g. roof trusses) and baled goods. The payload is loaded and unloaded from the top by cranes. Some side stanchion trailers are fitted with their own loading cranes. For safety reasons and easier handling ability with cranes, logs are bundled with cables and/or chains and tighteners.
- Open top trailers are designed primarily for the transportation of bulk and break-bulk freight that is not moisture-retentive (mostly mining products), metal objects (e.g. scrap metal, steel ingots, coiled steel, sheet steel and pipes), palletised freight (e.g. bricks, tiles and bottles) and in some cases non-palletised packaged freight. In the case of bulk freight, loading is performed by front-end loaders or by pouring commodities from the top. To unload bulk freight, some of these trailers can either be tipped sideways (in which case the sides are slanted) or to the rear (in which case the rear side has sturdy horizontal top hinges, i.e. a vertical flap-up side instead of a drop-side). Break-bulk freight is carried on trailers with drop sides. Break-bulk freight is loaded and unloaded from the side or the rear and is conducted either completely or partially manually using wheeled ramps and maneuverable belt or roller-bed conveyors, or through the use of forklift trucks, or from the top using cranes, or with a lift mounted at the rear end of the trailer (if there is no loading platform
- available where the vehicle can reverse up to), or a crane mounted at the front end of the payload section to load and unload freight from/to either side.