about concrete mixer truck
concretemachine > 05-30-2023, 06:29 AM
A truck or lorry is a motor vehicle designed to transport cargo, carry specialized payloads, or perform other utilitarian work. Trucks vary greatly in size, power, and configuration, but the vast majority feature body-on-frame construction, with a cabin that is independent of the payload portion of the vehicle. Smaller varieties may be mechanically similar to some automobiles. Commercial trucks can be very large and powerful and may be configured to be mounted with specialized equipment, such as in the case of refuse trucks, fire trucks, concrete mixers, and suction excavators. In American English, a commercial vehicle without a trailer or other articulation is formally a "straight truck" while one designed specifically to pull a trailer is not a truck but a "tractor".[1]
The majority of trucks currently in use are still powered by diesel engines, although small- to medium-size trucks with gasoline engines exist in the US, Canada, and Mexico. The market-share of electrically powered trucks is growing rapidly, expected to reach 7% globally by 2027, and electric motive force already predominates among both the largest and smallest trucks.[2] In the European Union, vehicles with a gross combination mass of up to 3.5 t (3.4 long tons; 3.9 short tons) are known as light commercial vehicles, and those over as large goods vehicles.
History
Steam wagons
A Sentinel steam wagon
Main article: Steam wagon
Trucks and cars have a common ancestor: the steam-powered fardier Nicolas-Joseph Cugnot built in 1769.[citation needed] However, steam wagons were not common until the mid-19th century. The roads of the time, built for horse and carriages, limited these vehicles to very short hauls, usually from a factory to the nearest railway station. The first semi-trailer appeared in 1881,[citation needed] towed by a steam tractor manufactured by De Dion-Bouton. Steam-powered wagons were sold in France and the United States until the eve of World War I, and 1935 in the United Kingdom, when a change in road tax rules made them uneconomic against the new diesel lorries.
Internal combustion
Daimler Motor-Lastwagen from 1898
In 1895, Karl Benz designed and built the first internal combustion truck. Later that year some of Benz's trucks were modified to become busses by Netphener. A year later, in 1896, another internal combustion engine truck was built by Gottlieb Daimler, the Daimler Motor Lastwagen.[3] Other companies, such as Peugeot, Renault and Büssing, also built their own versions. The first truck in the United States was built by Autocar in 1899 and was available with 5 or 8 horsepower (4 or 6 kW) engines.[4] Trucks of the era mostly used two-cylinder engines and had a carrying capacity of 1.5 to 2 t (3,300 to 4,400 lb). After World War I, several advances were made: electric starters, and 4, 6, and 8 cylinder engines.
Diesel engines
Although it had been invented in 1897, the diesel engine did not appear in production trucks until Benz introduced it in 1923.[5] The diesel engine was not common in trucks in Europe until the 1930s. In the United States, Autocar introduced diesel engines for heavy applications in the mid-1930s. Demand was high enough that Autocar launched the "DC" model (diesel conventional) in 1939. However, it took much longer for diesel engines to be broadly accepted in the US: gasoline engines were still in use on heavy trucks in the 1970s.[6][7]
Electric Motors
Main article: Electric truck
President Joe Biden test driving the Ford F-150 Lightning all-electric pick up at Ford's Rouge Electric Vehicle Center
Electrically powered trucks predate internal combustion ones and have been continuously available since the mid-19th-century. In the 1920s Autocar Trucks was the first of the major truck manufacturers to offer a range of electric trucks for sale.[8] Electric trucks were successful for urban delivery roles and as specialized work vehicles like forklifts and pushback tugs. The higher energy density of liquid fuels soon led to the decline of electric-powered trucks in favor of, first, gasoline, and then diesel and CNG-fueled engines until battery technology advanced in the 2000s when new chemistries and higher-volume production broadened the range of applicability of electric propulsion to trucks in many more roles. Today, manufacturers are electrifying all trucks ahead of national regulatory requirements, with long-range over-the-road trucks being the most challenging.[9][10]
Etymology
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Mannesmann Mulag truck at the Finlayson factory in Tampere, Finland in 1921
Truck is used in American English, and is common in Canada, Australia, New Zealand, Pakistan and South Africa, while lorry is the equivalent in British English, and is the usual term in countries like Ireland, Malaysia, Singapore and India.[original research?]
The first known usage of "truck" was in 1611 when it referred to the small strong wheels on ships' cannon carriages, and comes from "Trokhos" (Greek) = "wheel". In its extended usage, it came to refer to carts for carrying heavy loads, a meaning known since 1771. Its expanded application to "motor-powered load carrier" has been in usage since 1930, shortened from "motor truck", which dates back to 1901.[11][12]
"Lorry" has a more uncertain origin, but probably has its roots in the rail transport industry, where the word is known to have been used in 1838 to refer to a type of truck (a goods wagon as in British usage, not a bogie as in the American), specifically a large flat wagon. It might derive from the verb lurry (to carry or drag along, or to lug) which was in use as early as 1664, but that association is not definitive.[13] The expanded meaning of lorry, "self-propelled vehicle for carrying goods", has been in usage since 1911.[14][15]
International variance
A Japanese concrete mixer
Further information: List of truck types
In the United States, Canada, and the Philippines, "truck" is usually reserved for commercial vehicles larger than regular passenger cars, but includes large SUVs, pickups, and other vehicles with an open load bed. In Australia, New Zealand and South Africa, the word "truck" is mostly reserved for larger vehicles. In Australia and New Zealand, a pickup truck is frequently called a ute (short for "utility" vehicle),[16] while in South Africa it is called a bakkie (Afrikaans: "small open container"). In the United Kingdom, India, Malaysia, Singapore, Ireland, and Hong Kong lorry is used instead of truck, but only for the medium and heavy types, while truck is used almost exclusively to refer to pickups.
Types by size
See also: Truck classification and List of truck types
Ultra light
Might-E Truck from Canadian Electric Vehicles
Often produced as variations of golf cars, with internal combustion or battery electric drive, these are used typically for off-highway use on estates, golf courses, and parks. While not suitable for highway use some variations may be licensed as slow speed vehicles for operation on streets, generally as a body variation of a neighborhood electric vehicle. A few manufactures produce specialized chassis for this type of vehicle, while Zap Motors markets a version of their Xebra electric tricycle (licensable in the U.S. as a motorcycle).
Very light
A Piaggio Porter
Tata Super Ace in Indonesia
Popular in Europe and Asia, many mini-trucks are factory redesigns of light automobiles, usually with monocoque bodies. Specialized designs with substantial frames such as the Italian Piaggio shown here are based upon Japanese designs (in this case by Daihatsu) and are popular for use in "old town" sections of European cities that often have very narrow alleyways.
Regardless of name, these small trucks serve a wide range of uses. In Japan, they are regulated under the Kei car laws, which allow vehicle owners a break in taxes for buying a smaller and less-powerful vehicle (currently, the engine is limited to 660 cc displacement). These vehicles are used as on-road utility vehicles in Japan. These Japanese-made mini trucks that were manufactured for on-road use are competing with off-road ATVs in the United States, and import regulations require that these mini trucks have a 25 mph (40 km/h) speed governor as they are classified as low-speed vehicles.[17] These vehicles have found uses in construction, large campuses (government, university, and industrial), agriculture, cattle ranches, amusement parks, and replacements for golf carts.[18]
SML truck on the road in Accra
Major mini truck manufacturers and their brands:
Daihatsu Hijet
Honda Acty
Tata Ace
Mazda Scrum
Mitsubishi Minicab
Subaru Sambar
Suzuki Carry
Light
A Ford Ranger pickup truck
Light trucks are car-sized (in the US, no more than 13,900 lb (6.3 t)) and are used by individuals and businesses alike. In the EU they may not weigh more than 3.5 t (7,700 lb) and are allowed to be driven with a driving licence for cars. Pickup trucks, called utes in Australia and New Zealand, are common in North America and some regions of Latin America, Asia, and Africa, but not so in Europe, where this size of commercial vehicle is most often made as vans.
Medium
Fuso Canter, 8th Generation in Taiwan
Medium trucks are larger than light but smaller than heavy trucks. In the US, they are defined as weighing between 13,000 and 33,000 lb (5.9 and 15.0 t). For the UK and the EU the weight is between 3.5 to 7.5 t (7,700 to 16,500 lb). Local delivery and public service (dump trucks, garbage trucks and fire-fighting trucks) are normally around this size.
Heavy
A cement mixer is an example of a Class 8 heavy truck.
Seddon Atkinson Stratos refuse compactor
In Pakistan the majority of trucks are colorful and decorated.
Heavy trucks are the largest on-road trucks, Class 8. These include vocational applications such as heavy dump trucks, concrete pump trucks, and refuse hauling, as well as ubiquitous long-haul 4x2 and 6×4 tractor units.[19]
Road damage and wear increase very rapidly with the axle weight. The number of steering axles and the suspension type also influence the amount of the road wear. In many countries with good roads a six-axle truck may have a maximum weight of 44 t (97,000 lb) or more.
Off-road
ALMA antenna transporters are 20 m (65+2⁄3 ft) long, 10 m (32+7⁄9 ft) wide, weigh 130 t (127.9 long tons; 143.3 short tons) and drive on 28 tires.[20]
Off-road trucks include standard, extra heavy-duty highway-legal trucks, typically outfitted with off-road features such as a front driving axle and special tires for applications such as logging and construction, and purpose-built off-road vehicles unconstrained by weight limits, such as the Liebherr T 282B mining truck.
Maximum sizes by country
Further information: Road train
Australia has complex regulations over weight and length, including axle spacing, type of axle/axle group, rear overhang, kingpin to rear of trailer, drawbar length, ground clearance, as well as height and width laws. These limits are some of the highest in the world, a B-double can weigh 62.5 t (61.5 long tons; 68.9 short tons) and be 25 m (82 ft) long, and road trains used in the outback can weigh 172 t (169.3 long tons; 189.6 short tons) and be 53.5 m (176 ft) long.[21][22]
The European Union also has complex regulations. The number and spacing of axles, steering, single or dual tires, and suspension type all affect maximum weights. Length of a truck, of a trailer, from axle to hitch point, kingpin to rear of trailer, and turning radius are all regulated. In additions, there are special rules for carrying containers, and countries can set their own rules for local traffic.[23]
The United States Federal Bridge Law deals with the relation between the gross weight of the truck, the number of axles, the weight on and the spacing between the axles that the truck can have on the Interstate highway system.[24] Each State determines the maximum permissible vehicle, combination, and axle weight on state and local roads.
Country Maximum
with three axles With one trailer Maximum combination
Australia[21][22] 23 t (22.6 long tons; 25.4 short tons) 12 m (39 ft) 172 t (169.3 long tons; 189.6 short tons)
53.5 m (176 ft)
China[25] 25 t (24.6 long tons; 27.6 short tons)
12 m (39 ft) 49 t (48.2 long tons; 54.0 short tons)
16.5 m (54 ft) 55 t (54.1 long tons; 60.6 short tons)
18.75 m (62 ft)
EU[23] 26 t (25.6 long tons; 28.7 short tons)
12 m (39 ft) 16.5 m (54 ft) 44 t (43.3 long tons; 48.5 short tons)
18.75 m (62 ft)
Finland[26] 28 t (27.6 long tons; 30.9 short tons)
13 m (43 ft) 76 t (74.8 long tons; 83.8 short tons)
34.5 m (113 ft 2 in) 76 t (74.8 long tons; 83.8 short tons)
34.5 m (113 ft)
Ireland[27] 26 t (25.6 long tons; 28.7 short tons)
12 m (39 ft) 30 t (29.5 long tons; 33.1 short tons)
16.5 m (54 ft 2 in) 44 t (43.3 long tons; 48.5 short tons)
22 m (72 ft)
Sweden[28] 26 t (25.6 long tons; 28.7 short tons)
24 m (79 ft) 74 t (72.8 long tons; 81.6 short tons)
25.25 m (82 ft 10 in) 74 t (72.8 long tons; 81.6 short tons)
25.25 m (82.8 ft)
UK[29] 26 t (25.6 long tons; 28.7 short tons)
12 m (39 ft) 44 t (43.3 long tons; 48.5 short tons)
16.5 m (54 ft) 44 t (43.3 long tons; 48.5 short tons)
18.75 m (62 ft)
USA[30][31]
(Interstate) 54,000 lb (24 t)
45 ft (13.7 m) 80,000 lb (36 t)
none 80,000 lb (36 t)
none
Uniquely, the State of Michigan has a gross vehicle weight limit of 164,000 lb (74 t), which is twice the U.S. federal limit.[32][33][34] A measure to change the law was defeated in the Michigan Senate in 2019.[35][36][37][38][39]
Design
Almost all trucks share a common construction: they are made of a chassis, a cab, an area for placing cargo or equipment, axles, suspension and roadwheels, an engine and a drivetrain. Pneumatic, hydraulic, water, and electrical systems may also be present. Many also tow one or more trailers or semi-trailers.
Cab
A cabover truck
Streamlined conventional cab
Cab beside engine
The "cab", or "cabin" is an enclosed space where the driver is seated. A "sleeper" is a compartment attached to or integral with the cab where the driver can rest while not driving, sometimes seen in semi-trailer trucks.
There are several cab configurations:
"Cab over engine" (COE) or "flat nose"; where the driver is seated above the front axle and the engine. This design is almost ubiquitous in Europe, where overall truck lengths are strictly regulated, and is widely used in the rest of the world. They were common in North American heavy-duty trucks but lost prominence when permitted length was extended in the early 1980s. Nevertheless, this design is still popular in North America among medium- and light-duty trucks. To reach the engine, the whole cab tilts forward, earning this design the name of "tilt-cab". This type of cab is especially suited to the delivery conditions in Europe where many roads require the short turning radius afforded by the shorter wheelbase of the cab over engine layout.[40]
"Conventional" cabs seated the driver behind the engine, as in most passenger cars or pickup trucks. Many new cabs are very streamlined, with a sloped hood (bonnet) and other features to lower drag. Conventional cabs are the most common in North America, Australia, and China, and are known in the UK as "American cabs"[citation needed] and in the Netherlands as "torpedo cabs".
"Cab beside engine" designs are used for terminal tractors at shipping yards and for other specialist vehicles carrying long loads such as pipes. This type is often made by replacing the passenger side of a cab-over truck with an extended section of the load bed.
A further step from this is the side loading forklift that can be described as a specially fabricated vehicle with the same properties as a truck of this type, in addition to the ability to pick up its own load.
Engines and motors
Cummins ISB 6.7L medium-duty truck diesel engine
Most small trucks such as sport utility vehicles (SUVs), vans or pickups, and even light medium-duty trucks in North America, China, and Russia use gasoline engines (petrol engines), but many diesel engined models are now being produced. Most of the heavier trucks use four-stroke diesel engines with a turbocharger and intercooler. Huge off-highway trucks use locomotive-type engines such as a V12 Detroit Diesel two stroke engine. A large proportion of refuse trucks in the United States employ CNG (compressed natural gas) engines for their low fuel cost and reduced carbon emissions.
A significant proportion of North American manufactured trucks use an engine built by the last remaining major independent engine manufacturer (Cummins) but most global OEMs such as Volvo Trucks and Daimler AG promote their own "captive" engines.[41]
In the European Union, all new truck engines must comply with Euro VI emission regulations.[42]
As of 2019 several alternative technologies are competing to displace the use of diesel engines in heavy trucks. CNG engines are widely used in the US refuse industry and in concrete mixers, among other short-range vocations, but range limitations have prevented their broader uptake in freight hauling applications. Heavy electric trucks and hydrogen-powered trucks are new to the market in 2021,[43][44] but major freight haulers are interested.[45][46] Although cars will be first the phase-out of fossil fuel vehicles includes trucks.[47] According to The Economist magazine "Electric lorries will probably run on hydrogen, not batteries, which are too expensive."[48] Other researchers say that once faster chargers are available batteries will become competitive against diesel for all, except perhaps the heaviest, trucks.[49]
Drivetrain
A truck rear suspension and drive axles overview
Eaton Roadranger 18 speed "crash box" with automated gearshift
Small trucks use the same type of transmissions as almost all cars, having either an automatic transmission or a manual transmission with synchromesh (synchronizers). Bigger trucks often use manual transmissions without synchronizers, saving bulk and weight, although synchromesh transmissions are used in larger trucks as well. Transmissions without synchronizers, known as "crash boxes", require double-clutching for each shift, (which can lead to repetitive motion injuries), or a technique known colloquially as "floating", a method of changing gears which doesn't use the clutch, except for starts and stops, due to the physical effort of double-clutching, especially with non-power-assisted clutches, faster shifts, and less clutch wear.
Double-clutching allows the driver to control the engine and transmission revolutions to synchronize so that a smooth shift can be made; for example, when upshifting, the accelerator pedal is released and the clutch pedal is depressed while the gear lever is moved into neutral, the clutch pedal is then released and quickly pushed down again while the gear lever is moved to the next higher gear. Finally, the clutch pedal is released and the accelerator pedal pushed down to obtain the required engine speed. Although this is a relatively fast movement, perhaps a second or so while the transmission is in neutral, it allows the engine speed to drop and synchronize engine and transmission revolutions relative to the road speed. Downshifting is performed in a similar fashion, except the engine speed is now required to increase (while the transmission is in neutral) just the right amount in order to achieve the synchronization for a smooth, non-collision gear change. "Skip changing" is also widely used; in principle, the operation is the same as double-clutching, but it requires neutral be held slightly longer than a single-gear change.
Common North American setups include 9, 10, 13, 15, and 18 speeds. Automatic and automated manual transmissions for heavy trucks are becoming more and more common, due to advances both in transmission and engine power. In Europe, 8, 10, 12, and 16 gears are common on larger trucks with a manual transmission, while conventional automatic or automated manual transmissions would have anything from 5 to 12 gears. Almost all heavy truck transmissions are of the "range and split" (double H shift pattern) type, where range change and so‑called half gears or splits are air operated and always preselected before the main gear selection.
Frame
A truck rear frame (chassis) section view
Pickup truck frame (right rear view)
A truck frame consists of two parallel boxed (tubular) or C‑shaped rails, or beams, held together by crossmembers. These frames are referred to as ladder frames due to their resemblance to a ladder if tipped on end. The rails consist of a tall vertical section (two if boxed) and two shorter horizontal flanges. The height of the vertical section provides opposition to vertical flex when weight is applied to the top of the frame (beam resistance). Though typically flat the whole length on heavy-duty trucks, the rails may sometimes be tapered or arched for clearance around the engine or over the axles. The holes in rails are used either for mounting vehicle components and running wires and hoses or measuring and adjusting the orientation of the rails at the factory or repair shop.
The frame is usually made of steel, but can be made (whole or in part) of aluminum for a lighter weight. A tow bar may be found attached at one or both ends, but heavy tractors almost always make use of a fifth wheel hitch.[citation needed]
Body types
Box trucks ("tilts" in the UK) have walls and a roof, making an enclosed load space. The rear has doors for unloading; a side door is sometimes fitted.[50]
Chassis cab trucks have a fully enclosed cab at the front, with bare chassis frame-rails behind, suitable for subsequent permanent attachment of a specialized payload, like a fire-truck or ambulance body.
Concrete mixers have a rotating drum on an inclined axis, rotating in one direction to mix, and in the other to discharge the concrete down chutes. Because of the weight and power requirements of the drum body and rough construction sites, mixers have to be very heavy duty.[51][52]
Dump trucks ("tippers" in the UK) transport loose material such as sand, gravel, or dirt for construction. A typical dump truck has an open-box bed, which is hinged at the rear and lifts at the front, allowing the material in the bed to be unloaded ("dumped") on the ground behind the truck.[53][54]
Flatbed trucks have an entirely flat, level platform body. This allows for quick and easy loading but has no protection for the load. Hanging or removable sides are sometimes fitted.[55]
Refrigerator trucks have insulated panels as walls and a roof and floor, used for transporting fresh and frozen cargo such as ice cream, food, vegetables, and prescription drugs. They are mostly equipped with double-wing rear doors, but a side door is sometimes fitted.
Refuse trucks have a specialized body for collecting and, often, compacting trash collected from municipal, commercial, and industrial sites. This application has the widest use of the cab-over configuration in North America, to provide better maneuverability in tight situations. They are also among the most severe-duty and highest GVWR trucks on public roads.
Semi-tractors ("artics" in the UK) have a fifth wheel for towing a semi-trailer instead of a body.
Tank trucks ("tankers" in the UK) are designed to carry liquids or gases. They usually have a cylindrical tank lying horizontally on the chassis. Many variants exist due to the wide variety of liquids and gases that can be transported.[56]
Wreckers ("recovery lorries" in the UK) are used to recover and/or tow disabled vehicles. They are normally equipped with a boom with a cable; wheel/chassis lifts are becoming common on newer trucks.[57][58][59]
Sales and sales issues
Manufacturers
Main article: List of truck manufacturers
Truck market worldwide
Largest truck manufacturers in the world as of 2015.
Pos. Make Units
1 Daimler AG (Mercedes-Benz, Freightliner, Unimog, Western Star, Fuso, BharatBenz) 506,663[60]
2 Navistar International 359,000[61]
3 Dongfeng 336,869[62]
4 Tata 317,780[63]
5 Volvo Group (Volvo, Mack, Renault, UD Nissan) 207,475[64]
6 Volkswagen Group (MAN, Scania, Caminhões e Ônibus) 179,035[65]
7 Hino 162,870[66]
8 Paccar (DAF, Kenworth, Peterbilt, Leyland) 154,700[67]
9 Iveco 140,200[68]
Driving
In many countries, driving a truck requires a special driving license. The requirements and limitations vary with each different jurisdiction.
Australia
Inside a Mack truck
In Australia, a truck driver's license is required for any motor vehicle with a Gross Vehicle Mass (GVM) exceeding 4.5 t (4.4 long tons; 5.0 short tons). The motor vehicles classes are further expanded as:
Combination
HC: Heavy Combination, a typical prime mover plus semi-trailer combination.
MC: Multi Combination, e.g., B Doubles/road trains
Rigid
LR: Light rigid: a rigid vehicle with a GVM of more than 4.5 t (4.4 long tons; 5.0 short tons) but not more than 8 t (7.9 long tons; 8.8 short tons). Any towed trailer must not weigh more than 9 t (8.9 long tons; 9.9 short tons) GVM.
MR: Medium rigid: a rigid vehicle with 2 axles and a GVM of more than 8 t (7.9 long tons; 8.8 short tons). Any towed trailer must not weigh more than 9 t (8.9 long tons; 9.9 short tons) GVM. Also includes vehicles in class LR.
HR: Heavy Rigid: a rigid vehicle with three or more axles and a GVM of more than 8 t (7.9 long tons; 8.8 short tons). Any towed trailer must not weigh more than 9 t (8.9 long tons; 9.9 short tons) GVM. Also includes articulated buses and vehicles in class MR.
Heavy vehicle transmission
There is also a heavy vehicle transmission condition for a license class HC, HR, or MC test passed in a vehicle fitted with an automatic or synchromesh transmission; a driver's license will be restricted to vehicles of that class fitted with a synchromesh or automatic transmission. To have the condition removed, a person needs to pass a practical driving test in a vehicle with non-synchromesh transmission (constant mesh or crash box).[69]
Europe
Inside a Mercedes-Benz truck
Driving licensing has been harmonized throughout the European Union and the EEA (and practically all European non-member states), so that common rules apply within Europe (see European driving licence). As an overview, to drive a vehicle weighing more than 7.5 t (7.4 long tons; 8.3 short tons) for commercial purposes requires a specialist license (the type varies depending on the use of the vehicle and number of seats). For licenses first acquired after 1997, that weight was reduced to 3.5 t (3.4 long tons; 3.9 short tons), not including trailers.[citation needed]
Since 2013, the C1 license category allows driving vehicles over 3.5 and up to 7.5 tonnes. The C license category allows driving vehicles over 3.5 tonnes with a trailer up to 750 kg, and the CE category allows driving category C vehicles with a trailer over 750 kg.
South Africa
To drive any vehicle with a GVM exceeding 3.5 t (3.4 long tons; 3.9 short tons), a code C1 drivers license is required. Furthermore, if the vehicle exceeds 16 t (15.7 long tons; 17.6 short tons) a code C license becomes necessary.
To drive any vehicle in South Africa towing a trailer with a GVM more than 7.5 t (7.4 long tons; 8.3 short tons), further restrictions apply and the driver must possess a license suitable for the GVM of the total combination as well as an articulated endorsement. This is indicated with the letter "E" prefixing the license code.
In addition, any vehicle designed to carry goods or passengers may only be driven by a driver possessing a Public Driver's Permit, (or PrDP) of the applicable type. This is an additional license that is added to the DL card of the operator and subject to annual renewal unlike the five-year renewal period of a normal license.
The requirements for obtaining the different classes are below.
"G": Required for the transport of general goods, requires a criminal record check and a fee on issuing and renewal.
"P": Required for the transport of paying passengers, requires a more stringent criminal record check, additionally the driver must be over the age of 21 at time of issue. A G class PrDP will be issued at the same time.
"D": Required for the transport of dangerous materials, requires all of the same checks as class P., and in addition the driver must be over 25 at time of issue.
United States.