![Soratie Kalkkinen](https://upload.wikimedia.org/wikipedia/commons/8/80/Soratie_Kalkkinen.jpg)
A gravel road is a type of
unpaved
A road surface (British English), or pavement (American English), is the durable surface material laid down on an area intended to sustain vehicular or foot traffic, such as a road or walkway. In the past, gravel road surfaces, hoggin, cobble ...
road
A road is a linear way for the conveyance of traffic that mostly has an improved surface for use by vehicles (motorized and non-motorized) and pedestrians. Unlike streets, the main function of roads is transportation.
There are many types of ...
surfaced with
gravel
Gravel is a loose aggregation of rock fragments. Gravel occurs naturally throughout the world as a result of sedimentary and erosive geologic processes; it is also produced in large quantities commercially as crushed stone.
Gravel is classifi ...
that has been brought to the site from a
quarry
A quarry is a type of open-pit mine in which dimension stone, rock, construction aggregate, riprap, sand, gravel, or slate is excavated from the ground. The operation of quarries is regulated in some jurisdictions to reduce their envi ...
or
stream bed
A stream bed or streambed is the bottom of a stream or river (bathymetry) or the physical confine of the normal water flow (Channel (geography), channel). The lateral confines or channel margins are known as the stream Bank (geography), banks ...
. They are common in less-developed nations, and also in the rural areas of developed nations such as
Canada
Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...
and the
United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...
. In New Zealand, and other
Commonwealth
A commonwealth is a traditional English term for a political community founded for the common good. Historically, it has been synonymous with "republic". The noun "commonwealth", meaning "public welfare, general good or advantage", dates from the ...
countries, they may be known as
metal roads. They may be referred to as "dirt roads" in common speech, but that term is used more for
unimproved roads with no surface material added. If well constructed and maintained, a gravel road is an all-weather road.
Characteristics
Construction
Compared to
sealed road A sealed road is a road whose surface has been permanently sealed by the use of one of several pavement treatments, often of composite construction. In some countries, such as Australia and New Zealand, this surface is generically referred to as "s ...
s, which require large machinery to work and pour
concrete
Concrete is a composite material composed of fine and coarse aggregate bonded together with a fluid cement (cement paste) that hardens (cures) over time. Concrete is the second-most-used substance in the world after water, and is the most wi ...
or to lay and smooth a
bitumen
Asphalt, also known as bitumen (, ), is a sticky, black, highly viscous liquid or semi-solid form of petroleum. It may be found in natural deposits or may be a refined product, and is classed as a pitch. Before the 20th century, the term a ...
-based surface, gravel roads are easy and cheap to build. However, compared to
dirt road
A dirt road or track is a type of unpaved road not paved with asphalt, concrete, brick, or stone; made from the native material of the land surface through which it passes, known to highway engineers as subgrade material. Dirt roads are suitable ...
s, all-weather gravel highways are quite expensive to build, as they require
front loaders,
dump trucks
A dump truck, known also as a dumping truck, dump trailer, dumper trailer, dump lorry or dumper lorry or a dumper for short, is used for transporting materials (such as dirt, gravel, or demolition waste) for construction as well as coal. A typ ...
,
grader
A grader, also commonly referred to as a road grader, motor grader, or simply a blade, is a form of heavy equipment with a long blade used to create a flat surface during grading. Although the earliest models were towed behind horses, and lat ...
s, and
roadrollers
A road roller (sometimes called a roller-compactor, or just roller) is a compactor-type engineering vehicle used to compact soil, gravel, concrete, or asphalt in the construction of roads and foundations. Similar rollers are used also at lan ...
to provide a
base course
The base course or basecourse in pavements is a layer of material in an asphalt roadway, race track, riding arena, or sporting field. It is located under the surface layer consisting of the ''wearing course'' and sometimes an extra ''binder cour ...
of compacted earth or other material, sometimes
macadam
Macadam is a type of road construction, pioneered by Scottish engineer John Loudon McAdam around 1820, in which crushed stone is placed in shallow, convex layers and compacted thoroughly. A binding layer of stone dust (crushed stone from the o ...
ised, covered with one or more different layers of gravel. Graders are used to "blade" the road's surface (pass frequently to mix and distribute the gravel) to produce a more extreme
camber
Camber may refer to a variety of curvatures and angles:
* Camber angle, the angle made by the wheels of a vehicle
* Camber beam, an upward curvature of a joist to compensate for load deflection due in buildings
* Camber thrust in bike technology
* ...
compared to a paved road to aid drainage, to produce an "A" shaped surface to the road called a "crown", as well as to construct drainage ditches and
embankment
Embankment may refer to:
Geology and geography
* A levee, an artificial bank raised above the immediately surrounding land to redirect or prevent flooding by a river, lake or sea
* Embankment (earthworks), a raised bank to carry a road, railwa ...
s in low-lying areas.
Cellular confinement
Cellular confinement systems (CCS)—also known as geocells—are widely used in construction for erosion control, soil stabilization on flat ground and steep slopes, channel protection, and structural reinforcement for load support and earth ...
systems can be used to prevent the
washboarding
Washboarding or corrugation
is the formation of periodic, transverse ripples in the surface of gravel and dirt roads. Washboarding occurs in dry, granular road material
with repeated traffic, traveling at speeds above . Washboarding creates an ...
effect.
Construction of a gravel road begins with the base or subgrade layer. The expected road traffic volume and the average daily truck passage must be considered during the design process as they will influence the thickness of this layer, along with the balances of gravel and fines.
Geotextile
Geotextiles are permeable fabrics which, when used in association with soil, have the ability to separate, filter, reinforce, protect, or drain. Typically made from polypropylene or polyester, geotextile fabrics come in two basic forms: woven (re ...
fabric may be laid to improve the stability of the subgrade layer. When geotextile fabric is used, a gravel layer with a minimum thickness of 6" (15 cm)
is suggested to ensure the fabric remains unexposed. Road construction guidelines suggest that the crown in the road surface begins at the center point in the road, and does not exceed a 4% gradation from the center to the edge of the roadway.
The surface layer is constructed atop the subgrade layer. The amount of precipitation is taken into consideration for the selection of gravel size distribution. The surface layer will follow the crown established by the subgrade layer. Scarification of the subgrade layer prior to application of the surface gravel layer can be performed to increase the mixing and adherence between layers. Construction of the road surface is done gradually through multiple applications of layers of gravel, with compaction prior to the addition of the following layer. During reparation of a damaged road, ensuring that any washboarding, rutting, potholes, and erosion is adequately removed will minimize future need for reparation.
Windrow
A windrow is a row of cut (mown) hay or small grain crop. It is allowed to dry before being baled, combined, or rolled. For hay, the windrow is often formed by a hay rake, which rakes hay that has been cut by a mowing machine or by scythe into a ...
ing can be performed along the edges of roads in dry climates to allow easy access to gravel material for small repairs.
Materials
The gravel used consists of varying amount of crushed stone,
sand
Sand is a granular material composed of finely divided mineral particles. Sand has various compositions but is defined by its grain size. Sand grains are smaller than gravel and coarser than silt. Sand can also refer to a textural class of s ...
, and fines. Fines are
silt
Silt is granular material of a size between sand and clay and composed mostly of broken grains of quartz. Silt may occur as a soil (often mixed with sand or clay) or as sediment mixed in suspension with water. Silt usually has a floury feel when ...
or
clay
Clay is a type of fine-grained natural soil material containing clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4).
Clays develop plasticity when wet, due to a molecular film of water surrounding the clay par ...
particles smaller than , which can act as a binder. Crushed stone, also called road metal, is used because gravel with fractured faces will stay in place better than rounded river pebbles. A good gravel for a gravel road will have a higher percentage of fines than gravel used as a
subbase
In topology, a subbase (or subbasis, prebase, prebasis) for a topological space X with topology T is a subcollection B of T that generates T, in the sense that T is the smallest topology containing B. A slightly different definition is used by so ...
for a paved road. This often causes problems if a gravel road is paved without adding sand and gravel sized stone to dilute the percentage of fines.
A gravel road is quite different from a 'gravel drive', popular as private
driveway
A driveway (also called ''drive'' in UK English) is a type of private road for local access to one or a small group of structures, and is owned and maintained by an individual or group.
Driveways rarely have traffic lights, but some that bear ...
s in the
United Kingdom
The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and North ...
. This uses clean gravel consisting of uniform, rounded stones and small
pebble
A pebble is a clast of rock with a particle size of based on the Udden-Wentworth scale of sedimentology. Pebbles are generally considered larger than granules ( in diameter) and smaller than cobbles ( in diameter). A rock made predominant ...
s.
Laterite and murram roads
In
Africa
Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...
and parts of
Asia
Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an area ...
and
South America
South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the southe ...
,
laterite
Laterite is both a soil and a rock type rich in iron and aluminium and is commonly considered to have formed in hot and wet tropical areas. Nearly all laterites are of rusty-red coloration, because of high iron oxide content. They develop by ...
soils are used to build
dirt road
A dirt road or track is a type of unpaved road not paved with asphalt, concrete, brick, or stone; made from the native material of the land surface through which it passes, known to highway engineers as subgrade material. Dirt roads are suitable ...
s. However laterite, called ''murram'' in
East Africa
East Africa, Eastern Africa, or East of Africa, is the eastern subregion of the African continent. In the United Nations Statistics Division scheme of geographic regions, 10-11-(16*) territories make up Eastern Africa:
Due to the historical ...
, varies considerably in the proportion of stones (which are usually very small) to earth and sand. It ranges from a hard gravel to a softer earth embedded with small stones. Not all laterite and murram roads are therefore strictly gravel roads. Laterite and murram which contains a significant proportion of clay becomes very slippery when wet, and in the rainy season, it may be difficult even for
four-wheel drive
Four-wheel drive, also called 4×4 ("four by four") or 4WD, refers to a two-axled vehicle drivetrain capable of providing torque to all of its wheels simultaneously. It may be full-time or on-demand, and is typically linked via a transfer case ...
vehicles to avoid slipping off very
cambered roads into the drainage ditches at the side of the road. As it dries out, such laterite can become very hard, like
sun-dried brick
A mudbrick or mud-brick is an air-dried brick, made of a mixture of loam, mud, sand and water mixed with a binding material such as rice husks or straw. Mudbricks are known from 9000 BCE, though since 4000 BCE, bricks have also bee ...
s.
Maintenance
![Vedligehold af grusvej](https://upload.wikimedia.org/wikipedia/commons/9/9c/Vedligehold_af_grusvej.jpg)
Gravel roads require much more frequent maintenance than paved roads, especially after wet periods and when accommodating increased traffic. Wheel motion shoves material to the outside (as well as in-between travelled lanes), leading to rutting, reduced water-runoff, and eventual road destruction if unchecked. As long as the process is interrupted early enough, simple re-grading is sufficient, with material being pushed back into shape.
Segments of gravel roads on
grades
Grade most commonly refers to:
* Grade (education), a measurement of a student's performance
* Grade, the number of the year a student has reached in a given educational stage
* Grade (slope), the steepness of a slope
Grade or grading may also r ...
also
rut easily as a result of flowing water. When grading or building the road,
waterbar
A water bar or interceptor dyke is a road construction feature that is used to prevent erosion on sloping roads, cleared paths through woodland (for utility companies such as electricity pylons), or other accessways by reducing flow length. It is ...
s are used to direct water off the road. As an alternative method, humps can be formed in the gravel along the road to impede water flow, thereby reducing rutting.
Another problem with gravel roads is
washboarding
Washboarding or corrugation
is the formation of periodic, transverse ripples in the surface of gravel and dirt roads. Washboarding occurs in dry, granular road material
with repeated traffic, traveling at speeds above . Washboarding creates an ...
— the formation of corrugations across the surface at right angles to the direction of travel. Narrow-spaced washboarding can develop on gravel roads due to inconsistent moisture levels in the gravel, poor quality gravel, and vehicular stress to the road. Washboarding can also occur when graders exceed recommended speeds during the construction or maintenance phase causing the blade to bounce on the surface creating a pattern of widely-spaced corrugations. Corrugations from washboarding can become severe enough to cause vibration in vehicles so that bolts loosen or cracks form in components. Proper grading is needed to remove the corrugations, and reconstruction with careful choice of good quality gravel can help prevent them reforming. Additionally, installing a
cellular confinement system will prevent the washboard-like corrugations from occurring.
Gravel roads are often found in cold climates because they are less vulnerable to freeze / thaw damage than
asphalt
Asphalt, also known as bitumen (, ), is a sticky, black, highly viscous liquid or semi-solid form of petroleum. It may be found in natural deposits or may be a refined product, and is classed as a pitch. Before the 20th century, the term a ...
roads. The inferior surface of gravel is not an issue if the road is covered by snow and ice for extended periods.
Dust control
Dust control is routine practice on gravel roads in order to reduce the need for frequent maintenance, mitigate health concerns, and to prevent dust-related damage to roadside vegetation. Some common dust-suppression techniques are the application of a chloride solution (
calcium chloride
Calcium chloride is an inorganic compound, a salt with the chemical formula . It is a white crystalline solid at room temperature, and it is highly soluble in water. It can be created by neutralising hydrochloric acid with calcium hydroxide.
Ca ...
,
magnesium chloride
Magnesium chloride is the family of inorganic compounds with the formula , where x can range from 0 to 12. These salts are colorless or white solids that are highly soluble in water. These compounds and their solutions, both of which occur in natu ...
,
sodium chloride
Sodium chloride , commonly known as salt (although sea salt also contains other chemical salts), is an ionic compound with the chemical formula NaCl, representing a 1:1 ratio of sodium and chloride ions. With molar masses of 22.99 and 35.45 g ...
), the application of a
resin
In polymer chemistry and materials science, resin is a solid or highly viscous substance of plant or synthetic origin that is typically convertible into polymers. Resins are usually mixtures of organic compounds. This article focuses on natu ...
compound, or the incorporation of natural clay into the gravel mixture during the construction phase.
= Calcium chloride as a dust suppressant
=
Calcium chloride provides dust suppression through its
hygroscopic
Hygroscopy is the phenomenon of attracting and holding water molecules via either absorption or adsorption from the surrounding environment, which is usually at normal or room temperature. If water molecules become suspended among the substance ...
properties, allowing moisture to be drawn in and retained by the compound. Calcium chloride can be applied in either dry (pellet or flake) or wet (dissolved pre-prepared solution) form. Successful applications can be effective for up to three years, depending on the weather and traffic conditions for the roadway.
Dry application of this type of dust suppressant is begun by first preparing the road surface through grader passes, moving the top 5–8 cm of gravel creating windrows on the edges of the road. Calcium chloride is then applied to the road surface, and the road is then sprayed with water until the compound is dissolved. A grader "blades" the surface in numerous passes to ensure a uniform distribution of the compound. Compaction and the forming of the road surface is then performed to finalize the process.
[Caouette, Leo. 2013. APPLICATION METHODS CALCIUM CHLORIDE AS A DUST SUPPRESSANT. Nunavut: Nunavut Municipal Training Organization. https://www.nmto.ca/sites/default/files/application_of_calcium_chloride.pdf.]
Wet application begins by spraying the road surface with a 30% concentration solution of calcium chloride. After the solution is applied, the top 5–8 cm of gravel is mixed through numerous passes of a grader. The road is then formed and compacted.
Driving
Although well-constructed and graded gravel roads are suitable for speeds of up to 100 km/h (60 mph), driving on them requires far more attention to variations of the surface, and it is easier to lose control than on a paved road. In addition to potholes, ruts and loose stony or sandy ridges at the edges or in the middle of the road, problems associated with driving on gravel roads include:
*sharper and larger stones cutting and puncturing tires, or being thrown up by the wheels and damaging the underside, especially puncturing the fuel tank of unmodified cars
*stones skipping up hitting the
car body, lights or
windshield
The windshield (North American English) or windscreen (Commonwealth English) of an aircraft, car, bus, motorbike, truck, train, boat or streetcar is the front window, which provides visibility while protecting occupants from the elements. Mo ...
s when two vehicles pass at high speed
*dust thrown up from a passing vehicle reducing visibility
*'
washboard' corrugations cause loss of control or damage to vehicles due to excessive
vibration
Vibration is a mechanical phenomenon whereby oscillations occur about an equilibrium point. The word comes from Latin ''vibrationem'' ("shaking, brandishing"). The oscillations may be periodic function, periodic, such as the motion of a pendulum ...
. These are most often found near intersections as stopping or braking causes them to form or otherwise if heavy farm or other equipment often uses these roads.
*skidding on mud after rain
*vehicle
fishtailing
Fishtailing is a vehicle handling problem which occurs when the rear wheels lose traction, resulting in oversteer. This can be caused by low friction surfaces (sand, gravel, rain, snow, ice, etc.). Rear-drive vehicles with sufficient power can ...
as a result of ruts in the surface of the gravel. Often found on frequently traveled roads.
*In higher rainfall areas, the increased camber required to drain water, and open drainage ditches at the sides of the road, often cause vehicles with a high
centre of gravity
In physics, the center of mass of a distribution of mass in space (sometimes referred to as the balance point) is the unique point where the weighted relative position of the distributed mass sums to zero. This is the point to which a force may ...
, such as trucks and off-road vehicles, to overturn if they do not keep close to the crown of the road.
*Excess dust permeates door-opening rubber moulding, breaking the seal.
*Lost binder in the form of road dust, when mixed with rain, will wear away the painted surfaces of vehicles.
*Many gravel roads are only
one lane wide or slightly larger, thus requiring special attention when driving at higher speeds.
Related types
Resource road
According to the
British Columbia
British Columbia (commonly abbreviated as BC) is the westernmost province of Canada, situated between the Pacific Ocean and the Rocky Mountains. It has a diverse geography, with rugged landscapes that include rocky coastlines, sandy beaches, ...
Ministry of Forests, resource roads are typically "one- or two-lane gravel roads built for industrial purposes to access natural resources in remote areas".
They may be used by industrial vehicles or the general public, and as a link to rural communities.
Driving on resource roads can be hazardous for many reasons, including limited
visibility
The visibility is the measure of the distance at which an object or light can be clearly discerned. In meteorology it depends on the transparency of the surrounding air and as such, it is unchanging no matter the ambient light level or time of ...
, unusual
road geometry, and the presence of
wildlife
Wildlife refers to domestication, undomesticated animal species (biology), species, but has come to include all organisms that grow or live wilderness, wild in an area without being species, introduced by humans. Wildlife was also synonymous ...
.
Disused resource roads can pose a danger to both drivers and passersby, due to the danger of
landslide
Landslides, also known as landslips, are several forms of mass wasting that may include a wide range of ground movements, such as rockfalls, deep-seated grade (slope), slope failures, mudflows, and debris flows. Landslides occur in a variety of ...
s forming on unstable,
poorly-drained ground.
Forest service road
A forest service road is a type of rudimentary access road, built by the
United States Forest Service
The United States Forest Service (USFS) is an agency of the U.S. Department of Agriculture that administers the nation's 154 national forests and 20 national grasslands. The Forest Service manages of land. Major divisions of the agency inc ...
to access remote undeveloped areas. These roads are built mainly for the purposes of the
logging industry
Logging is the process of cutting, processing, and moving trees to a location for transport. It may include skidder, skidding, on-site processing, and loading of trees or trunk (botany), logs onto logging truck, trucks or flatcar#Skeleton car, ...
and
forest management Forest management is a branch of forestry concerned with overall administrative, legal, economic, and social aspects, as well as scientific and technical aspects, such as silviculture, protection, and forest regulation. This includes management for ...
workers, although in some cases they are also used for
backcountry
In the United States, a backcountry or backwater is a geographical area that is remote, undeveloped, isolated, or difficult to access.
Terminology Backcountry and wilderness within United States national parks
The National Park Service (NPS) ...
recreation access.
Networks of tributary roads branch off from a
trunk FSR. Roads are usually named after a regional district, and branches have an
alphanumeric
Alphanumericals or alphanumeric characters are a combination of alphabetical and numerical characters. More specifically, they are the collection of Latin letters and Arabic digits. An alphanumeric code is an identifier made of alphanumeric ch ...
designation.
Typically, a high-clearance four-wheel drive vehicle is required to travel effectively on a road, especially where large
pothole
A pothole is a depression in a road surface, usually asphalt pavement, where traffic has removed broken pieces of the pavement. It is usually the result of water in the underlying soil structure and traffic passing over the affected area. Water ...
s and/or
waterbar
A water bar or interceptor dyke is a road construction feature that is used to prevent erosion on sloping roads, cleared paths through woodland (for utility companies such as electricity pylons), or other accessways by reducing flow length. It is ...
s are present.
Switchbacks are employed to make the road passable through steep terrain.
These roads rapidly fall into disrepair and quickly become impassable. Remnants of old roads can exist for decades. They are eventually erased by
washout,
erosion
Erosion is the action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth's crust, and then transports it to another location where it is deposited. Erosion is distin ...
, and
ecological succession
Ecological succession is the process of change in the species structure of an ecological community over time. The time scale can be decades (for example, after a wildfire) or more or less.
Bacteria allows for the cycling of nutrients such as ca ...
.
Logging road
![Dans la forêt d'Eseka1](https://upload.wikimedia.org/wikipedia/commons/4/4c/Dans_la_for%C3%AAt_d%27Eseka1.jpg)
Logging
roads
A road is a linear way for the conveyance of traffic that mostly has an improved surface for use by vehicles (motorized and non-motorized) and pedestrians. Unlike streets, the main function of roads is transportation.
There are many types of ...
are constructed to provide access to the forest for
logging
Logging is the process of cutting, processing, and moving trees to a location for transport. It may include skidding, on-site processing, and loading of trees or logs onto trucks or skeleton cars.
Logging is the beginning of a supply chain ...
and other
forest management Forest management is a branch of forestry concerned with overall administrative, legal, economic, and social aspects, as well as scientific and technical aspects, such as silviculture, protection, and forest regulation. This includes management for ...
operations. They are commonly narrow, winding, and unpaved, but main haul roads can be widened, straightened or paved if traffic volume warrants it.
The choice of
road design
Highway engineering is an engineering discipline branching from civil engineering that involves the planning, design, construction, operation, and maintenance of roads, bridges, and tunnels to ensure safe and effective transportation of people and ...
standards Standard may refer to:
Symbols
* Colours, standards and guidons, kinds of military signs
* Standard (emblem), a type of a large symbol or emblem used for identification
Norms, conventions or requirements
* Standard (metrology), an object th ...
is a tradeoff between construction costs and haul costs (which the road is designed to reduce). A road that serves only a few stands will be used by relatively few trucks over its lifetime and so it makes sense to save construction costs with a narrow, winding, unpaved road that adds to the time (and haul costs) of the few trips. A main haul road serving a large area, however, will be used by many trucks each day, and each trip will be shorter (saving time and money) if the road is straighter and wider, with a smoother surface.
Logging truck
A logging truck or timber lorry is a large truck used to carry logs. Some have integrated flatbeds, some are discrete tractor units, and some are configured to spread a load between the tractor unit and a dollied trailer pulled behind it. Ofte ...
s are generally given right of way. In areas that the practice is regulate,d on non-highway roads with heavy logging traffic may be "radio-controlled", meaning that a
CB radio
Citizens band radio (also known as CB radio), used in many countries, is a land mobile radio system, a system allowing short-distance person-to-many persons bidirectional voice communication among individuals, using two way radios operating on ...
on board any vehicle on the road is advised for safety reasons.
Image gallery
File:Saviselkä 2.JPG, Gravel road at the Saviselkä village in Kärsämäki
Kärsämäki (; literally meaning "snout hill") is a municipality of Finland. It is located in the province of Oulu and is part of the Northern Ostrobothnia region. The municipality has a population of () and covers an area of of which is water ...
, Finland
File:Rrgrade.jpg, Logging railroad
A forest railway, forest tram, timber line, logging railway or logging railroad is a mode of railway transport which is used for forestry tasks, primarily the transportation of felled logs to sawmills or railway stations.
In most cases this form ...
converted to logging truck
A logging truck or timber lorry is a large truck used to carry logs. Some have integrated flatbeds, some are discrete tractor units, and some are configured to spread a load between the tractor unit and a dollied trailer pulled behind it. Ofte ...
use in northwest Oregon
File:Gravel Road Coober Pedy.jpg, Gravel road south of Coober Pedy
Coober Pedy () is a town in northern South Australia, north of Adelaide on the Stuart Highway. The town is sometimes referred to as the "opal capital of the world" because of the quantity of precious opals that are mined there. Coober Pedy is ...
File:Chase khar - چاسه خار (3).jpg, Gravel road in Iran
File:Tamsa.JPG, A gravel road between the villages of Tamsa and Laguja
Laguja is a small village in Nõo Municipality, Tartu County, Estonia
Estonia, formally the Republic of Estonia, is a country by the Baltic Sea in Northern Europe. It is bordered to the north by the Gulf of Finland across from Finl ...
, Estonia
File:Gravel1.jpg, A close-up of a gravel road in Terre Haute, Indiana
Terre Haute ( ) is a city in and the county seat of Vigo County, Indiana, United States, about 5 miles east of the state's western border with Illinois. As of the 2010 census, the city had a population of 60,785 and its metropolitan area had a ...
File:Gravel road, Namibia.jpg, Gravel road in Namibia
Namibia (, ), officially the Republic of Namibia, is a country in Southern Africa. Its western border is the Atlantic Ocean. It shares land borders with Zambia and Angola to the north, Botswana to the east and South Africa to the south and ea ...
Unpaved roads length by country
See also
References
External links
*
Environmentally Sensitive Maintenance Practices for Dirt and Gravel RoadsU.S. Forest Service
The United States Forest Service (USFS) is an agency of the U.S. Department of Agriculture that administers the nation's 154 national forests and 20 national grasslands. The Forest Service manages of land. Major divisions of the agency in ...
{{Authority control
Types of roads
Stone (material)
*