A semi-trailer truck, also known as a semi, tractor-trailer, or (in the United Kingdom and Ireland) articulated truck or articulated lorry, (colloquially abbreviated to artic) is an articulated vehicle consisting of a towing engine (tractor in the United States, prime mover in Australia or truck in Ireland, the United Kingdom, Canada and New Zealand), and a semi-trailer (plus possible additional trailers) that carries the freight. A semi-trailer does not trail completely behind the towing vehicle, but is attached at a point that is just forward of the rear-most axle of the towing unit, so that some fraction of the weight of the trailer is carried by the prime mover, with most of that at the rear axle (s) of the prime mover, but a small amount at the front axle (s). This arrangement requires both tractor and semi-trailer to be distinct in design from a rigid truck and trailer.
Colloquial terms for semi-trailer truck include truck and trailer, transfer truck, 18-wheeler, semi, Mack truck (named for a prominent brand), big rig (US), transport (Canada), artic (UK and Ireland), lorry (UK).
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In North America semi tractors usually have 3 axles. The front, or "steer" axle, having two wheels and each of the two rear, or "drive" axles, having "dual wheels" (double wheels). Thus, the most common configuration of tractor has 10 wheels; however, in some cases dual wheels are replaced by tires known as "super singles" (see below), or wide-base singles, to reduce the weight of the tractor. (The weight reduction is about 180 pounds (82 kg) per axle when using super singles). In this case the tractor will only have six wheels. A tractor having a single drive axle (six wheeler) is often used to pull shorter trailers in tight urban environments, such as downtown areas where a 60-foot (18 m) rig would be difficult to maneuver, or in applications where only lighter loads are transported. Tractors with a single drive axle usually are not equipped with a Sleeper. Many tractors are equipped with a movable fifth_wheel (hitch point) to allow adjusting the weight distribution.
The cargo trailer usually has a "tandem" axle pair at the rear, each of which has dual wheels, or eight wheels on the trailer. Many trailers are equipped with a movable tandem to allow adjusting the weight distribution.
Although the sum of the weights of the tractor and the trailer (the gross weight) is normally limited to a certain amount, some roads and bridges are marked with a different gross weight restriction to prevent damage. Cargoes that exceed allowed weights are usually marked with overweight load and must obtain a permit to use certain roads.
Rules governing the maximum size and weight of vehicles differ from one U.S. state to another. However, since the majority of hauling is done on the interstate system, the vast majority of trucks and trailers made in the U.S. are built to the specifications of the Department of Transportation (DOT), which governs the use of the interstate system. The DOT has established these vehicle limits: 102 inches (2.6 m) wide, 13.5 feet (4.1 m) feet in height, and 80,000 pounds (36,000 kg) gross weight. The weight limit is further restricted with a limit of 34,000 pounds (15,000 kg) per tandem axle and 20,000 pounds (9,100 kg) per single axle. [2] These limits can be exceeded as individual states have the right to issue temporary oversize and/or overweight permits.
Trailer dimensions vary greatly, depending on the amount and type of cargo it was designed to haul. (See types of trailers under Construction, below.)
Although dual wheels are most common, use of two single, wider tires (known as "super singles") on each axle is becoming popular, initially among bulk cargo carriers and other weight-sensitive operators. With a growing desire to reduce greenhouse gas emissions the use of the super single tire is gaining popularity. The three advantages of this configuration are : (1) super singles reduce fuel consumption. Testing on an oval track (Canada 2009) showed 10% fuel savings when using super singles. The savings come from less energy wasted flexing tire side walls. Fewer tire side walls equates to less wasted energy; (2) the lighter tire weight allows a truck to be loaded with more freight; (3) the single wheel covers less of the brake unit, which allows faster cooling and reduces brake fade.
Perhaps the largest disadvantage is the lack of redundancy. Should a tire becomes deflated or destroyed, there isn't another tire attached to the same a hub to maintain the dynamic stability of the vehicle. With dual wheels the remaining tire may be overloaded, but it will typically allow the vehicle to be safely stopped or driven to a repair facility. (Note: it is illegal to drive a commercial vehicle with a deflated or destroyed tire).
Another innovation rapidly growing in popularity is the skirted trailer. The area between the road and the bottom of the trailer frame was previously left open, however the air moving under the trailer is a source of aerodynamic drag. Oval track testing (Canada 2009) proved it is possible to improve fuel economy by 8%, depending on the design and installation configuration of the trailer skirt. The more completely the airflow under the trailer is blocked the better the improvement in fuel economy.
The United States also allows 2-axle tractors to tow two 1-axle 28.5 feet (8.7 m) semi-trailers known officially as STAA doubles and colloquially as doubles, a set, or a set of joints on all highways that are part of the National Network. The second trailer in a set of doubles uses a converter gear, also known as a con-gear or dolly. This apparatus supports the front half of the second trailer. Individual states may further allow longer vehicles (known as "longer combination vehicles" or LCVs), and may allow them to operate on roads other than those part of the National Network.
LCV types include:
Regulations on LCVs vary widely from state to state. No state allows more than three trailers without a special permit. Reasons for limiting the legal trailer configurations include both safety concerns and the impracticality of designing and constructing roads that can accommodate the larger wheelbase of these vehicles and the larger minimum turning radii associated with them.
Most states restrict operation of larger tandem trailer setups such as triple units, the "Turnpike Double" (twin 48–53 ft units) or the "Rocky Mountain Double." (A full 48–53 ft unit and a shorter 28 ft unit) In general, these types of setups are restricted to tolled turnpikes, such as I-80 through Ohio and Indiana and specific Western states. Tandem setups are not restricted to certain roads any more than a single setup. The exception are the units listed above. They are also not restricted because of weather or "difficulty" of operation.
The long-haul tractors used in interstate travel are often equipped with a sleeper behind the driver's cab, which can be anything from a small bunk to a rather elaborate miniature apartment.
The noticeable difference between tractor units in the U.S. and Europe is that almost all European models are "cab over engine" (COE or forward control), while the majority of U.S. trucks are conventional (or normal control). For repairs, the entire cab hinges forward to allow maintenance access. European trucks, whether small rigid or fully articulated, have a sheer face on the front. This allows for shorter trucks with longer trailers (with larger freight capacity) within the legal maximum total length. Furthermore, it offers greater manoeuvrability and better overview for the driver. In Europe the entire length of the vehicle is measured as total length, while in U.S. the cabin of the truck is normally not part of the measurement.
In Europe usually only the rear tractor axle has twin wheels, while larger size single wheels are used for the cargo trailer. The most common combination used in Europe is a semi tractor with two axles and a cargo trailer with three axles, giving five axles and 12 wheels in total. Lesser used (common in Scandinavia) are tractors with three axles, which feature twin wheels either on one or both rear axles. In addition to the most common three axles variant, cargo trailers with only two or only one axle are in use, again usually with larger single wheels.
In the UK, to carry the maximum permitted gross weight of 44,000 kg (97,000 lb), both tractor and semi-trailer must have 3 or more axles each. In practice, there is no legal height limit; however, bridges over 16.5 ft (5.03 m) do not have the height marked on them. No heavier vehicles are permitted on the UK road network, except for indivisible loads, which would be classed as abnormal (or oversize); these vehicles are required to display an STGO (Special Types General Order) plate on the front of the prime mover and, under certain circumstances, are required to travel by an authorised route and have an escort.
In the UK, some articulated trucks have 8 tires on 3 axles on the tractor; these are known as 6-wheelers or "6 leggers", with either the centre or rear axle having single wheels which normally steer as well as the front axle and can be raised when not needed (i.e. when unloaded or only a light load is being carried; an arrangement known as a TAG axle). Some trailers have 2 axles which have twin wheels on each axle; other trailers have 3 axles, of which 1 axle can be a TAG axle which has super-single wheels. In the UK, two wheels bolted to the same hub are classed as a single wheel, therefore a standard six-axle articulated truck is considered to have twelve wheels, even though it has twenty tyres. The UK also allows artic truck tractors which have 6 tyres on 2 axles; these are known as 4-wheelers.
Most UK trailers are 45 feet (13.5 metres) long and, dependent on the position of the fifth wheel and kingpin, a coupled tractor unit and trailer will have a combined length of between 50 and 55 feet (15.25 and 16.75 metres). Although the Construction and Use Regulations allow a maximum rigid length of 60 feet (18.2 metres), this, combined with a shallow kingpin and fifth wheel set close to the rear of the tractor unit, can give an overall length of around 75 feet (22.75 metres), although combinations of this length are usually used only to carry steel or concrete beams. Providing certain requirements are fulfilled, a Special Types General Order (STGO) allows for vehicles of any size or weight to travel on UK roads. However, in practice any such vehicle has to travel by a route authorised by the Department of Transport and move under escort. The escort of abnormal loads in the UK is now predominantly carried out by private companies, but extremely large or heavy loads that require road closures must still be escorted by the police.
As a result of a desk study into Longer Heavier Vehicles, as of 2009 the consequences of increasing the length of semi-trailers in the UK are being considered, although the study ruled out the adoption of other more wide reaching changes to weight, axle number and length limits, with options up to 11-axle, 34m long, 82 tonne road trains studied.
The maximum overall length applying in the EU and EEA member states is 18.75 metres with a maximum weight of 40 tonnes, or 44 tonnes if carrying an ISO container.[1] However, rules limiting the semi-trailers to 16.5 metres and 18.75 are met with trucks carrying a standardized 7.82 metre body with one additional 7.82 metre body on tow as a trailer.[2] Since 1996, when Sweden and Finland formally won a final exemption from the European Economic Area rules with 60- tonne and 25.25- metre combinations, all other member states gained the ability to adopt the same rules.
The 25.25 metres truck combinations were developed under the branding of EcoCombi which influenced the name of EuroCombi for an ongoing standardization effort where such truck combinations shall be legal to operate in all jurisdictions of the European Economic Area. With the 50% increase in cargo weight, the fuel efficiency increases with an average of 20% with a corresponding relative decrease in carbon emissions and with the added benefit of a third less trucks on the road.[1] The 1996 EU regulation defines a Europe Module System (EMS) as it was implemented in Sweden. The wording of EMS combinations and EuroCombi are now used interchangeably to point to truck combinations as specified in the EU document; however apart from Sweden and Finland the EuroCombi is only allowed to operate on specific tracks in other EU member states.
From 2006, 25.25 m truck trailer combinations are to be allowed on restricted routes within Germany, following a similar (on-going) trial in The Netherlands. Similarly, Denmark have allowed 25.25 metre combinations on select routes. Like in Sweden and Finland, these vehicles in continental Europe will run a 60 ton weight limit. Two types are to be used: 1) a 26 ton truck pulling a dolly and semi-trailer, or 2) an articulated tractor unit pulling a b-double. The UK government has so far decided not to have its own trial of these 60 ton vehicles, but to keep an eye on the other countries' trials.
When using a dolly, which generally has to be equipped with lights and a license plate, rigid trucks can be used to pull semitrailers. The dolly is equipped with a fifth wheel to which the trailer is coupled. Because the dolly attaches to a pintle hitch on the truck, maneuvering a trailer hooked to a dolly is different from maneuvering a fifth wheel trailer. Backing the vehicle requires same technique as backing an ordinary truck/full trailer combination, though the dolly/semi setup is probably longer, thus requiring more space for maneuvering. The tractor-semitrailer configuration is rarely used on timber trucks, since these will use the two big advantages of having the weight of the load on the drive wheels, and the loader crane used to lift the logs from the ground can be mounted on the rear of the truck behind the load, allowing a short (lightweight) crane to reach both ends of the vehicle without uncoupling. Also construction trucks are more often seen in a rigid + midaxle trailer configuration instead of the tractor + semitrailer setup.
Denmark, the Netherlands and Norway all allow 25.25 m trucks (the Netherlands from 2000, Denmark from 2008, and Norway from 2008 on selected routes).
In Sweden the allowed length is 24 metres (78.7 ft) since 1967. Before that, the maximum length was unlimited - the only limitations were on axle load. What stopped Sweden from adopting the same rules as the rest of Europe, when securing road safety was the national importance of a competitive forestry industry.[1] Finland with the same road safety issues and equally important forestry industry followed suit. The change made trucks able to carry three stacks of cut-to-length logs instead of two, as it would be in a short combination. They have one on stack together with a crane on the 6x4 truck, and two additional stacks on a four axle trailer. The allowed gross weight in both countries is up to 60 tonnes (130,000 lb) depending on the distance between the first and last axle.
In the negotiations starting in the late 80s preceding the two countries' entries to the European Economic Area and later the European Union, they insisted on exemptions from the EU rules citing environmental concerns and the transportation needs of the logging industry. In 1995, after Sweden and Finland's entry to the union, the rules changed again, this time to allow trucks carrying a standard CEN unit of 7.82 metres to draw a 13.6 metres standard semi-trailer on a dolly, a total overall length of 25.25 metres (82.8 ft). Later B-double combinations came into use, often with one 20 ft container on the b-link and a 40 ft container (or two 20 ft containers) on a semi-trailer bed. In allowing the longer truck combinations, what would take two 16.5 metre semi-trailer trucks and one 18.75 metre truck and trailer to haul on the continent now could be handled by just two 25.25 metre trucks - greatly reducing overall costs and emissions.
However, longer and heavier combinations are regularly seen on public roads - special permits are issued for special cargo - not a too uncommon occurrence. Others are: The mining company Boliden AB have a standing special permit for 80 ton combinations on select routes between mines in the inland and the processing plant in Boliden, taking a load of 50 ton ore. Volvo has a special permit for a 32 metres (105 ft), steering B-trailer-trailer combination carrying two 40 ft containers to and from Gothenburgs harbour and Volvo Trucks factory, all on the island of Hisingen.[3] Another example is the ongoing project En Trave Till (lit. One more pile/stack) started in December 2008. It will allow even longer vehicles to further rationalize the logging transports. As the name of the project points out, it will be able to carry four stacks of timber, instead of the usual three. The test is limited to Norrbotten county and the European route E4 between the timber terminal in Överkalix and the sawmill in Munksund (outside Piteå). The vehicle is a 30 metre long truck trailer combination with a gross weight exceeding 90 tonnes (200,000 lb). It is estimated that this will give a 20% lower cost and 20-25% CO2 emissions reduction compared to if the timber instead would have been transported with regular 60 ton truck combinations. As the combinations spreads its weight over more axles, braking distance, road wear and traffic safety is believed to be either the same or improved with the 90 ton truck-trailer. In the same program two types of 74 tonnes (160,000 lb) combinations will be tested in Dalsland and Bohuslän counties in western Sweden. A enhanced truck and trailer combination for use in the forest and a b-double for plain highway transportation to the mill in Skoghall.
Australian road transport has a reputation for using very large trucks and road trains. This is reflected in the most popular configurations of trucks generally having dual drive axles and three axles on the trailers, with 4 tires on each axle. This means that Australian single semi-trailer trucks will usually have 22 wheels which is generally more than their counterparts in other countries. Long haul transport usually operates as B-doubles with two trailers (each with three axles), for a total of nine axles (including steering). In some lighter duty applications only one of the rear axles of the truck is driven, and the trailer may have only two axles.
From July 2007 the Australian Federal and State Governments allowed the introduction of B-triple trucks on a specified network of roads.[4] B-Triples are set up differently to conventional road trains. The front of their first trailer is supported by the turntable on the prime mover. The second and third trailers are supported by turntables on the trailers in front of them. As a result, B-Triples are much more stable than road trains and handle exceptionally well. True road trains only operate in remote areas, regulated by each state or territory government.
In total, the maximum length that any articulated vehicle may be (without a special permit and escort) is 53.5 metres (175.5 ft), its maximum load may be up to 164 tons (361,558 lb) gross and may have up to 4 trailers. However, heavy restrictions apply to the areas where such a vehicle may travel in most states. In remote areas such as the Northern Territory great care must be taken when sharing the road with longer articulated vehicles that often travel during the day time, especially 4 trailer road trains.
In most areas a truck is generally limited to two trailers and a total length of 26 metres (85 ft) and in urban areas this length limit is further reduced to 19 metres (62 ft). 25 or 26 metre - with permits from state authorities - (82 ft to 85 ft), 62.5 ton (137,788 lb) B-doubles are very common in all parts of Australia including state capitals and on major routes may outnumber single trailer configurations.
In Australia, both conventional tractor units and cabovers are common, however cabovers are most often seen on B-Doubles on the eastern seaboard where the reduction in total length allows the vehicle to pull longer trailers and thus more cargo than it would otherwise.
Super single tires are sometimes used on tri-axle trailers. The suspension is designed with travel limiting, which will hold the rim off the road for one blown or deflated tire for each side of the trailer, so a trailer can be driven at reduced speed to a safe place for repair. Super singles are also often used on the steer axle in Australia to allow greater loading over the steer axle. The increase in loading of steer tires requires a permit.
These are for tractor units, not straight, rigid, box or other heavy vehicles.
There are many types of semi-trailers in use, designed to haul a wide range of products. See semi-trailer for more detail.
The cargo trailer is, by means of a king pin, hooked to a horseshoe-shaped quick-release coupling device called a fifth wheel or a turntable hitch at the rear of the towing engine that allows easy hook up and release. The truck trailer cannot move by itself because it only has wheels at the rear end, hence the name semi-trailer: it requires a forward axle, provided by the towing engine, to carry half the load weight. The vehicle has a tendency to fold at the pivot point between the semi and the trailer when braking hard at high speeds. Such a truck accident is called a 'trailer swing', although it is commonly described as a 'jackknife'. 'Jackknifing' is a condition where the tractive unit swings round against the trailer: not vice-versa. See: jackknifing.
Semi trucks use air pressure, rather than hydraulic fluid, to actuate the brakes mainly due to the much larger braking forces required. This also allows for ease of coupling and uncoupling of trailers from the tractor unit, as well as reducing the potential for problems common to hydraulic systems, such as leakage or brake failure caused when overheated brake fluid vaporizes in the hydraulic lines. The most common failure is "brake fade," usually caused when the drums or discs and the linings of the brakes overheat from excessive use.
The parking brake of the tractor unit and the emergency brakes of the trailer are spring brakes that require air pressure in order to be released. They are applied when air pressure is released from the system, and disengaged when air pressure is supplied. This is an emergency feature which ensures that if air pressure to either unit is lost, the trailer will stop to a grinding halt instead of not stopping and becoming uncontrollable.
The trailer controls are coupled to the tractor through two "glad-hand" connectors, which provide air pressure, and an electrical cable, which provides power to the lights and any specialized features of the trailer.
"Glad-hand" connectors (also known as "palm couplings,") are air hose connectors, each of which has a flat engaging face and retaining tabs. The faces are placed together, and the units are rotated so that the tabs engage each other to hold the connectors together. This arrangement provides a secure connection, but allows the couplers to break away without damaging the equipment if they are pulled, as may happen when the tractor and trailer are separated without first uncoupling the air lines. These connectors are similar in design to the ones used for a similar purpose between railroad cars. Two air lines control the trailer unit. An emergency or main air supply line pressurizes the trailer's air tank and disengages the emergency brake, and a second service line controls the brake application.
In the UK male/female quick release connectors "red line" or emergency, have a female on the truck and male on the trailer and a "yellow line" or service has a male on the truck and female on the trailer. This avoids coupling errors (causing no brakes) plus the connections will not come apart if pulled by accident. The three electrical lines will fit one way round a primary black a secondary green and an ABS lead, all of these lines are collectively known as "suzies" or "suzie coils".
Another braking feature of semi-trucks is the engine braking, which could be either compression brake (usually shortened to "Jake brake") or exhaust brake or combination of both. The use of compression brake alone however produces a loud and distinctive noise, and owing to noise pollution, some local municipalities have prohibited or restricted the use of engine brake systems inside their jurisdictions, particularly in residential areas. The advantage to using this instead of conventional brakes is that a truck can travel down a long grade without overheating its wheel brakes. Some vehicles can also be equipped with hydraulic or electric retarders which have an advantage of near silent operation.
Because of the wide variety of loads the "semi" may carry, they usually have a manual transmission to allow the driver to have as much control as possible. However, all truck manufacturers now offer semi-automatic transmissions (manual gearboxes with automated gear change), as well as automatic transmissions.
"Semi" truck transmissions can have as few as 9 forward speeds or as many as 18 forward speeds (plus 2 reverse speeds). A large number of transmission ratios means the driver can operate the engine more efficiently. Modern on-highway diesel engines are designed to provide maximum torque in a narrow RPM range (usually 1200-1500 RPM); having more gear ratios means the driver can hold the engine in its optimum range regardless of road speed (drive axle ratio is also a critical factor).
A ten speed manual transmission, for example is controlled via a six-slot H-box pattern, similar to that in five-speed cars — five forward and one reverse gear. Gears six to ten (and high speed reverse) are accessed by a Lo/High range splitter; gears 1-5 are Lo range; gears 6-10 are High range using the same shift pattern. A Super-10 transmission, by contrast, has no range splitter; it uses alternating "stick and button" shifting (stick shifts 1-3-5-7-9, button shifts 2-4-6-8-10). 13,15 and 18 speed transmission have the same basic shift pattern, but include a splitter button to access to additional ratios found in each range.
Another difference between semi-trucks and cars is the way the clutch is set up. On an automobile, the clutch pedal is depressed full stroke to the floor for every gear shift to ensure the gearbox is disengaged from the engine. On a semi-truck with constant mesh transmission (non synchronized), such as by the Eaton Roadranger series, not only is double clutching required, but a clutch brake is required as well. The clutch brake stops the rotation of the gears, and allows the truck to be put into gear without grinding when stationary. The clutch is pressed to the floor only to allow smooth engagement of low gears when starting from a full stop; when moving, the clutch pedal is pressed only far enough to break torque for gear changes.
An electrical connection is made between the tractor and the trailer through a cable often referred to as a "pigtail." This cable is a bundle of wires in a single casing. Each wire controls one of the electrical circuits on the trailer, such as running lights, brake lights, turn signals, etc. A standard cable would break when the rig went around corners so it is coiled and retains these coils when not under tension. It is these coils that cause the cable to look like a pigtail.
In most countries a trailer or semi-trailer must have minimum
This is an assembly hanging down from the bottom of the rear of the trailer. It is intended to provide some protection for cars which start to run into the rear of the trailer. This came into use in the aftermath of the accident that killed Jayne Mansfield on June 29, 1967; the car she was in hit the rear of a tractor-trailer. The bottom of the rear of the trailer is near head level for an adult in a car, and without the underride guard, the only protection for such an adult's head in such an accident would be the car's windshield.
A special driver's license is required to operate various commercial vehicles.
Regulations vary by province. A license to operate a vehicle with air brakes is required (i.e., normally a Class I, II, or III commercial license with an "A" or "S" endorsement in provinces other than Ontario). In Ontario, a "Z" endorsement [5] is required to drive any vehicle using air brakes; in provinces other than Ontario, the "A" endorsement is for air brake operation only, and an "S" endorsement is for both operation and adjustment of air brakes. Anyone holding a valid Ontario driver's license (i.e., excluding a motorcycle license) with a "Z" endorsement can legally drive any air-brake-equipped truck-trailer combination with a registered- or actual-gross-vehicle-weight (i.e., including towing- and towed-vehicle) up to 11 metric tonnes, that includes one trailer weighing no more than 4.6 tonnes if the license falls under the following three classes: Class E (school bus—maximum 24-passenger capacity or ambulance), F (regular bus—maximum 24-passenger capacity or ambulance) or G (car, van, or small-truck). A Class B (any school bus), C (any urban-transit-vehicle or highway-coach), or D (heavy trucks other than tractor-trailers) license enables its holder to drive any truck-trailer combination with a registered- or actual-gross-vehicle-weight (i.e., including towing- and towed-vehicle) greater than 11 tonnes, that includes one trailer weighing no more than 4.6 tonnes.[6] Anyone holding an Ontario Class A license (or its equivalent) can drive any truck-trailer combination with a registered- or actual-gross-vehicle-weight (i.e., including towing- and towed-vehicles) greater than 11 tonnes, that includes one or more trailers weighing more than 4.6 metric tonnes.
Drivers of semi-trailer trucks generally require a Class A commercial driver's license to operate any combination vehicles with a Gross Vehicle Weight Rating (or GVWR) in excess of 26,000 pounds (11.8 t). Some states (such as North Dakota) provide exemptions for farmers, allowing non-commercial license holders to operate semis within a certain range of their farm within the state. Also a person under the age of 21 cannot operate a commercial vehicle outside the state where the commercial license was issued. A person must be at least 18 in order to be issued a commercial license.
In addition, Endorsements are necessary for certain cargo and vehicle arrangements and types;
The Road Traffic Security Rules (zh:道路交通安全規則) require a combination vehicle driver license (Chinese: 聯結車駕駛執照) to drive a combination vehicle (Chinese: 聯結車). These rules define a combination vehicle as a motor vehicle towing a heavy trailer, i.e., a trailer with a gross weight of more than 750 kilograms (1,653 lb).
A category CE driving license is required to drive an articulated lorry.
Truck drivers in Australia require an endorsed license. These endorsements are gained through training and experience. The minimum age to hold an endorsed licence is 18 years, and/or must have held open (full) driver's licence for minimum 12 months. The following are the heavy vehicle license classes in Australia:
In New Zealand drivers of heavy vehicles require specific licences, termed as 'classes'. A Class 1 Drivers Licence (aka a Car License) will allow the driving of any vehicle with Gross Laden Weight (GLW) or Gross Combination Weight (GCW) of 4500 kg or less. For other types of vehicles the Classes are separately licensed as follows:
Further information on the New Zealand Licensing system for Heavy Vehicles can be found at Land Transport New Zealand.
Modern day semi-trailer trucks often operate as a part of a domestic or international transport infrastructure to support containerized cargo shipment. Various types of rail flat bed train cars are modified to hold the cargo trailer or container with wheels or without. This is called "Intermodal" or "piggy-back" or "piggyback". The system allows the cargo to switch from the highway to railway or vice versa with relative ease by using gantry cranes.
The large trailers pulled by a tractor unit come in many styles, lengths, and shapes. Some common types are: vans, reefers, flatbeds, sidelifts and tankers. These trailers may be refrigerated, heated, ventilated, or pressurized, depending on climate and cargo. Some trailers have movable wheel axles that can be adjusted by moving them on a track underneath the trailer body and securing them in place with large pins. The purpose of this is to help adjust weight distribution over the various axles, to comply with local laws.