A
semi-trailer truck, also known as
tractor-trailer or (in the United Kingdom
and Ireland
)
articulated truck or
articulated lorry, often
abbreviated to artic, is an articulated vehicle consisting of a
towing engine (tractor in the
United
States
, prime mover in Australia, tractor unit in Ireland and
truck in the UK, Canada
and New Zealand
), and a semi-trailer
(plus possible additional trailer)
that carries the freight.
Colloquial terms for semi-trailer truck include
truck and
trailer,
transfer truck,
18-wheeler,
semi,
Diesel,
Mack
truck (named for a prominent brand),
big
rig (US),
transport (Canada),
artic (UK and Ireland), and
juggernaut (UK).
Regional Configurations
North America
Tractor unit hauling tractor units in
Idaho
Rocky Mountain Double
In North America, semi tractors usually have 3
axles, the front, or "
steer",
axle having two wheels, and each of the two rear, "drive", axles
having a pair of "dualies"(double) wheels on each side. 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 lbs per axle when using super singles). In this case
the tractor will only have six wheels. A smaller 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 rig would be too difficult to maneuver. These tractors
are referred to as day cabs and do not have sleepers.
The
cargo trailer usually has two
"
tandem" axles at the rear, each of which has
dual wheels, or 8 wheels on the trailer. Many trailers are equipped
with movable tandems and fifth wheels that can be set to adjust the
weight on each axle to stay within legal limits.
Although the cargo's weight added to the semi's weight can equal a
certain amount of gross some roads are marked with a different
gross restriction so the roads are not damaged. 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
between states in the US. However, since the majority of hauling is
done on the interstate system, the vast majority of trucks and
trailers made in the US are built to the specifications of the
Department of Transportation (D.O.T.), which governs the use of the
interstate system. The D.O.T. has established these vehicle limits:
102 inches wide, 13.5 feet in height, and 80,000 lbs gross weight.
[5083] 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, particularly among
bulk cargo carriers and other weight-sensitive operators. The three
advantages of this configuration are :(1) the lighter tire weight
allows a truck to be loaded with more freight(2) the single wheel
covers less of the brake unit, which allows faster cooling and
reduces
brake fade.(3) super singles
reduce fuel consumption. Testing on an oval track showed 5% 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.
The biggest disadvantage is that when a tire becomes deflated or
destroyed, it is not possible to drive the vehicle to a service
location without risking damage to the
rim, as
it is with dual wheels.
The United States also allows 2-axle tractors to tow two 1-axle
28.5-foot (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
LCV), and may allow them to operate on roads
other than those part of the National Network.
LCV types include:
- Triples: Three 28.5-foot (8.7 m) trailers; maximum weight
up to 129,000 pounds (58.5 t).
- Turnpike Doubles: Two 48-foot (14.6 m) trailers; maximum
weight up to 147,000 pounds (66.7 t)
- Rocky Mountain Doubles: One 40 (12.2 m) to 53
(16.2 m) foot trailer (though usually no more than 48 feet)
and one 28.5-foot (8.7 m) trailer (known as a "pup"); maximum weight
up to 129,000 pounds (58.5 t)
- In Canada, a Turnpike Double is two 53-foot trailers and a
Rocky Mountain Double is a 50-foot trailer with 24-foot "pup"
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 select 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.
Europe
The noticeable difference between
tractor
units in the U.S. and Europe is that most European models are
"
cab over engine" (
COE or
forward control), while most 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 greater maneuverability, as the driver need
only
gauge distances behind his seating
point, and this allows for shorter trucks with longer trailers
(with larger freight capacity) within the legal maximum total
length. 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.
Most semi tractors have two axles, again with the front, steer,
having two wheels, and rear, drive, having twin wheels on each
side. Thus, the most common configuration has six wheels. The cargo
trailer usually has three axles at the rear, with single wheels, or
six wheels in total. The entire vehicle thus usually has five axles
and 12 wheels in total, although the trailers can vary in number of
wheels.
United Kingdom
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
[5084]. 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 tyres 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 meters) 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 meters). Although the Construction and Use Regulations allow
a maximum rigid length of 60 feet (18.2 meters), 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
meters), 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.
Continental Europe
The maximum overall length applying in the
EU and
EEA member states are 18.75 meters with a
maximum weight of 40 ton, or 44 ton if carrying a
ISO container. However, rules limits the
semi-trailers to 16.5 meters and 18.75 is met with trucks carrying
a standardized 7.82 meter body with one additional 7.82 meter body
on tow as a trailer. Since 1996, when Sweden and Finland formally
got a final exemption from the
European Economic Area rules with 60
ton and 25.25 meter combinations all other member states got 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. 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
meter combinations on select routs. 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
log 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.
The largest trailer manufacturer in Europe is
Schmitz Cargobull.
Denmark, the Netherlands, Norway, Sweden and Finland
Denmark, the Netherlands and Norway all allow 25,25 m trucks (the
Netherlands from 2000, Denmark and Norway from 2008).
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. 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
depending on the distance between the first and last axle.
In the negotiations starting in the late 80's 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 meter to draw a 13.6 meters 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 meter
semi-trailer trucks and one 18.75 meter truck and trailer to haul
on the continent now could be handled by just two 25.25 meter
trucks - greatly reducing overall costs and emissions.
A 30 meter/90 ton combination.
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 , 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
.
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 meter long truck
trailer combination with a gross weight exceeding . It's 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. The braking
distance, road wear, and traffic safety will be either the same or
improved with the 90 ton truck-trailer.
In the same program
two types of 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
.
Australia
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. 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 metre
(82 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.
Semi-truck manufacturers
These are for semi-trailer tractor
units, not straight, rigid, box or other heavy vehicles.
- Used in the United States:
- Used in Europe:
- Used in Japan and some other Asia Pacific regions:
- Other countries:
Construction
[[File:Conventional 18-wheeler truck diagram.PNG|frame|center|Side
view and underside view of a
conventional 18-wheeler
semi-trailer truck with an enclosed cargo space. The
underside view shows the arrangement of the 18
tires (wheels). Shown in blue in the underside view are
the
axles,
drive
shaft, and
differentials. The legend
for labeled parts of the truck is as follows:
1.
tractor unit
2.
semi-trailer (detachable)
3.
engine compartment
4.
cabin
5. sleeper (not present in all trucks)
6. air dam
7.
fuel tanks
8.
fifth wheel coupling
9. enclosed
cargo space
10. landing gear - legs for when semi-trailer is detached]]
Types of trailers
There are many types of semi-trailers in use, designed to haul a
wide range of products. See
semi-trailer for more detail.
Coupling and uncoupling
The cargo trailer is, by means of a nipple called the
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 only carries half its own 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.
Braking
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, that unit will not lose all braking capacity and
become uncontrollable.
A view of semi-trailer "Suzies" at
the back of an Australian prime mover.
The "red" line is emergency/supply and the "blue" is control
line.
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.
Transmission
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
usually provide at least nine or ten
gear
ratios, but possibly as many as eighteen (e.g. Australian
road trains). A large number of
transmission ratios means the
internal combustion engine itself
can operate within a narrow range of speeds. The range of speeds
over which an engine is expected to perform well has implications
for the design — the narrower the range, the more the engine can be
optimised for that range. Also, having so many gears allows
fine-grained control of
engine
braking for better control on downhills and in curves.
A ten speed manual transmission 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 toggling a selector control for the range change
low/high, so that first gear becomes sixth, second becomes seventh,
etc.
Another difference between semi-trucks and cars is the way the
clutch is set up. On a
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 bottom of the clutch pedal
stroke is where the clutch brake activates and as a result only
partial or "half" clutch pedal stroke is used when a vehicle is in
motion.
Lights
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
- 2 rear lights (red)
- 2 stop lights (red)
- 2 turning lights; one for right and one for left, flashing
(yellow, orange or red)
- 2 marking lights behind if wider than certain specifications
(red; 3 lights in North America)
- 2 marking lights front if wider than the truck or wider than
certain specifications (white; 3 amber lights in North
America)
Drivers license
A special
driver's license is
required to operate various commercial vehicles.
Canada
Regulations vary by province. A license to operate a vehicle with
air brakes is required, normally a Class I commercial license.
In
Ontario
, a "Z" endorsement is required to drive any vehicle
using air brakes. Anyone holding an Ontario "Z" endorsement
can drive a heavy truck with up to one towed vehicle, weighing no
more than 4.6
metric tons if he or she
also holds a Class A (tractor-trailer), B (school bus), C (regular
bus) or D (heavy trucks other than tractor trailers) licence.
Anyone holding an Ontario Class A licence or equivalent can drive a
tractor-trailer combination with at least 2 towed vehicles
(
Ibid.).
In
Manitoba
, one requires a class 1 license, with an "A" or "S"
endorsement to operate a semi-truck. An "A" endorsement is
for air brakes, and an "S" endorsement is operation of air brakes,
plus adjustment of them.
United States
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 .
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;
- H - Hazardous Materials
(HazMat or HM) - necessary if materials require HM placards.
- N - Tankers - the driver is acquainted with the unique handling
characteristics of liquids tankers.
- X - Signifies Hazardous Materials and Tanker endorsements,
combined.
- T - Doubles & Triples - the licensee may pull more than one
trailer.
- P - Buses - Any Vehicle designed to transport 16 or more
passengers (including the driver).
- S - School Buses - Any school bus designed to transport 11 or
more passengers (including the driver).
- W - Tow Truck
Taiwan
Taiwanese sign prohibiting heavy
trailers
The Road Traffic Security Rules (
zh:道路交通安全規則)
require a combination vehicle driver license ( ) to drive a
combination vehicle ( ). 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 .
Europe
A category C+E
driving
licence is required to drive an articulated lorry.
Australia
Truck drivers in Australia require an endorsed license. These
endorsements are gained through training and experience. The
minimum age to hold an endorsed license is 18 years, and/or must
have held open (full) driver's license for minimum 12 months.The
following are the heavy vehicle license classes in Australia:
- LR- A Light Rigid 'Class LR' covers a rigid vehicle with a GVM
of more than 4.5 tons but not more than 8 tons. Any towed trailer
must not weigh more than 9 tons GVM. Also includes vehicles with a
GVM up to 8 tons which carry more than 12 adult including the
driver and vehicles in class 'C'.
- MR- A Medium Rigid 'Class MR' covers a rigid vehicle with 2
axles and a GVM of more than 8 tons. Any towed trailer must not
weigh more than 9 tons GVM. Also includes vehicles in class
'LR'.
- HR- A Heavy Rigid 'Class HR' covers a rigid vehicle with 3 or
more axles and a GVM of more than 15 tons. Any towed trailer must
not weigh more than 9 tons GVM. Also includes articulated buses and
vehicles in class 'MR'.
- HC (Heavy Combination)- A 'Class HC' Licence covers heavy
combination vehicles like a prime mover towing a semi-trailer, or
rigid vehicles towing a trailer with a GVM of more than 9 tons.
Also includes vehicles in class 'HR'.
- MC (Multi Combination)- A 'Class MC' Licence covers
multi-combination vehicles like Road Trains and B-Double Vehicles.
Also includes vehicles in class 'HC'.
New Zealand
In New Zealand drivers of heavy vehicles require specific licenses,
termed as 'classes'. A Class 1 Drivers License (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:
- `Class 2 - Medium Rigid Vehicle' - Any rigid vehicle with GLW
less than 18,001 kg (with Light Trailer up to 3500 kg or
less), any combination vehicle with GCW less than 12,001 kg,
any rigid vehicle of any weight with no more than 2 axles, or any
Class 1 vehicle.
- 'Class 3 - Medium Combination Vehicle' - Any combination
vehicle of GCW less than 25,001 kg or any Class 2
vehicle.
- 'Class 4 - Heavy Rigid Vehicle' - Any rigid vehicle of any
weight, any Combination vehicle which consists of a heavy vehicle
and a light trailer, or any vehicle of Class 1 or 2 (but not
3).
- 'Class 5 - Heavy Combination Vehicle' - Any combination vehicle
of any weight, and any vehicle covered by previous classes.
- 'Class 6' is a Motorcycle License.
Further information on the New Zealand Licensing system for Heavy
Vehicles can be found at
Land Transport New Zealand.
Role in industry
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.
Media
- NBC ran two popular TV series about truck
drivers in the 1970s, Movin'
On (1974-1976) and B.J.
and the Bear (1978-1981). Each featured actor Claude Akins in major roles.
- A pop song by C.W. McCall called "Convoy" spurred sales of CB radios, with an imaginary trucking story.
- The "trucker's movie" Smokey and the Bandit was second
only to Star
Wars in box office gross when released in 1977.
- Another "trucker's movie" Black
Dog features an ex-trucker who takes an illegal load of
guns to save his family's home. There are hijacking attempts and stunt driving action
scenes.
- Steven Spielberg's 1971 film
"Duel" features a Peterbilt 281 tanker truck as the villain.
- Stephen King's 1986 film
Maximum Overdrive
featured big rigs as its primary homicidal
villains.
- Tractor-trailers appear in the 1980s cartoon The Transformers as the
Autobots' leader Optimus Prime (Convoy in Japanese
version), their second-in-command Ultra Magnus, and as the Stunticons' leader Motormaster. (The latter considers himself
Optimus Prime's rival for the title "King of the Road".)
Optimus Prime returned in the 2007
film.
- The eighteen-wheeled truck was immortalized in numerous
country music songs.
- William
Henkin, actor from a suburb of Chicago, had the stage name "Big
Rig" when he appeared in various featurettes on Broadway
.
- CMT has a TV show called Trick My Truck where truckers get their
trucks 'tricked out'.
- The History Channel's
Ice Road Truckers charts
two months in the lives of six men who haul supplies to diamond
mines over frozen lakes that double as roads.
- The American television show Knight Rider featured a
semi-trailer truck called 'The Semi', operated by the Foundation
for Law & Government (F.L.A.G.) as a mobile support facility
for KITT. Also, in two episodes KITT faced off against an armored
semi called Goliath.
- Truck.Net
has a website dedicated to US Trucking Information started in
1996.
- TruckNetUK.com has a website dedicated to Trucking
Information in UK and Europe.
- Ol' Blue,
USA has a website for Safety and Education in and around big
trucks in the US as well as an AskTheLaw section also in print and
on radio where questions can be directed to commercial law
enforcement.
See also
References
- Wideberg, J et al
[www.mne.psu.edu/ifrtt/ConferenceProceedings/ISHVWD_9_2006/docs/pdfs/session%206/s6-2%2090.pdf
"Study Of Stability Measures And Legislation Of Heavy Articulated
Vehicles In Different OECD Countries" (PDF)] University of
Seville, KTH
and Scania May 2006
- Ramberg, K "Fewer Trucks Improve the Environment" (PDF)
Svenskt Näringsliv October
2004
- The next environmental improvement - Long truck
rigs Volvo Trucks Magazine 2008-10-03
- [1] Press release: VAILE ANNOUNCES THE B-TRIPLE
ROAD NETWORK
- "Z" endorsement
- Ontario drivers classes
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