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Road

A road is an identifiable route or path between two or more places. Roads are typically smoothed, paved, or otherwise prepared to allow easy travel; though they need not be, and historically many roads were simply recognisable routes without any formal construction or maintenance. In urban areas Urban area

An urban area is an area with an increased density [i] of human-created structures in comparison to the ... 

 roads may pass along and be named as street Street

A street is a public [i] parcel of land [i] adjoining building [i]s in an urban [i] ... 

s, serving a dual function as urban space and route.

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Timeline

1970   Discovery in England England

England is the largest and most populous constituent country [i] of the United Kingdom [i]. ... 

 of the Sweet Track, the World's oldest engineered roadway.



Encyclopedia


A road is an identifiable route or path between two or more places. Roads are typically smoothed, paved, or otherwise prepared to allow easy travel; though they need not be, and historically many roads were simply recognisable routes without any formal construction or maintenance. In urban areas Urban area

An urban area is an area with an increased density [i] of human-created structures in comparison to the ... 

 roads may pass along and be named as street Street

A street is a public [i] parcel of land [i] adjoining building [i]s in an urban [i] ... 

s, serving a dual function as urban space and route.

Usage and etymology



In original usage, a "road" was simply any thing worth reading. The word “street,” whose origin is the Latin Latin

Latin is an ancient Indo-European language [i] originally spoken in Latium [i], ... 

 strata, was kept for paved Pavement (material)

Pavement in American English [i] refers to the durable surface for an area intended to sustain traffic, ... 

 pathways that had been prepared to ease travel in some way. Thus, many "Roman Roads" have the word "street" as part of their name.

However, modern usage does not usually make this distinction and it is only important since place names often hold the earlier usage in them; these days, roads are also prepared in some way. This includes, at the least, the removal of trees and smoothing of the ground. In some dialects, lower grade roads are called trail Trail

A trail or footpath is a pedestrian road [i] mainly used for recreational walking [i], but often a ... 

s and tracks and it is uncertain where "road" begins and trail ends. Roads are a prerequisite for road transport Road transport

Road transport or road transportation is transport [i] on road [i]s, that is most transport over ... 

 of goods on wheel Wheel

A wheel is a round object that, together with an axle [i], allows low friction [i] in motion by rolling [i] ... 

ed vehicle Vehicle

This article is about the means of transport.... 

s.

The word “road” emphasizes its function of transportation along its length, while a “street” may be considered to have activity and commerce taking place on it .

History


The first pathways were the trails Trail

A trail or footpath is a pedestrian road [i] mainly used for recreational walking [i], but often a ... 

 made by migrating Migration

Migration occurs when living things move from one biome [i] to another.... 

 animals. By about 10,000 BC, these rough pathways were used by human hunter nomad Nomad

Communities of nomadic people move from place to place, rather than settling down [i] in one loc ... 

s following these herds.

Street paving has been found from the first human settlements around 4000 BC see India's Indus Valley city Harrapa.

The oldest engineered road discovered is the Sweet Track causeway Causeway

In modern usage, a causeway is a road or railway elevated by a bank, usually across a broad body of water [i] ... 

 in England England

England is the largest and most populous constituent country [i] of the United Kingdom [i]. ... 

, dating from around 3800 BC.

The ancient Egypt Ancient Egypt

Ancient Egypt was a long-lived ancient civilization [i] in north-eastern Africa [i]. ... 

ians constructed a stone paved road to help move materials for the building of the Great Pyramid in about 3000 BC.

The ancient Chinese History of China

The history of China is detailed by historical records dating as far back as 16th century BC [i]. ... 

 constructed an extensive system of roads, some paved, from about 1100 BC onwards. By 20 AD, the Chinese road network extended over 40,000 kilometres.

The Incas built fine highways, the Inca road system Inca road system

For the Frank Zappa [i] song, see Inca Roads [i]
... 

, for couriers through the Andes Andes

The Andes is the world's longest mountain range [i], forming a continuous chain of highland along the w ... 

, and the Mayans built an extensive network of paved roads in Mexico Mexico

The United Mexican States, generally known as Mexico is a country [i] located in North America [i] ... 

 before the European discovery of the New World New World

The New World is one of the names used for the Americas [i].... 

.

In ancient times, transport by river River

A river is a large natural waterway [i]. ... 

 was far easier and faster than transport by road, especially considering the cost of road construction and the difference in carrying capacity between cart Cart

A cart is a vehicle [i] or device using two wheel [i]s and normally one horse [i], for transport [i].... 

s and river barge Barge

A barge is a flat-bottomed boat [i], built mainly for river [i] and canal [i] transport of heavy goods. ... 

s. A hybrid of road transport and ship transport is the horse-drawn boat in which the horse follows a cleared path along the river bank.

In 500 BC, Darius I the Great Darius I of Persia

Darius the Great [i] , was the son of Hystaspes [i], and Persian Emperor [i] ... 

 started an extensive road system for Persia Persian Empire

The Persian Empire was a series of historical empires that ruled over the Iranian plateau [i] ... 

 , including the famous Royal Road Royal Road

The Persian Royal Road was an ancient highway built by the Persian [i] king Darius I [i] ... 

 which was one of the finest highways of its time. The road was used even after the Roman times. Because of the road's superior quality, mail couriers could travel 2,699 km in seven days.

From about 300 BC, the Roman Empire Roman Empire

The Roman Empire was a phase of the ancient Roman [i] civilization characterized by an autocratic [i] ... 

 built straight strong stone Roman road Roman road

The Roman road [i]s were essential for the growth of their empire [i], by enabling them to... 

s throughout Europe and North Africa North Africa

North Africa or Northern Africa is the northernmost [i] region [i] of the Africa [i]n continent [i] ... 

, in support of its military campaigns. By the 1st century the Roman Empire was connected by 85,000 kilometers of paved roads.

Road construction and maintenance in Britain was traditionally done on a local parish basis. This resulted in a poor and variable state of roads. To remedy this, the first of the 'Turnpike Trusts' around 1706, to build good roads and collect tolls from passing vehicles. Eventually there were approximately 1,100 Trusts in Britain and some 38,000 km of engineered roads.

Engineered roads in the age of horse-drawn transport aimed for a maximum gradient of 1 in 30 on a macadamized surface, since this was the steepest a horse could exert to pull a load up hill, which it could manage easily on the flat. Notable road engineers from this period are Pierre Marie Jérôme Trésaguet  in France and John Loudon McAdam John Loudon McAdam

John Loudon McAdam was a Scottish [i] engineer [i] and road [i]-builder. ... 

  in England.

During the industrial revolution Industrial Revolution

The Industrial Revolution was the major technological [i], socioeconomic [i] a ... 

, the railway Rail transport

Rail transport is the transport [i] of passenger [i]s and goods [i] along railways or ... 

 developed as a solution to the problem of rutting of the road surface by heavy carts. Instead of trying to build a strong surface across the whole road, the cart was constrained to run either on rails or grooves which could be made of much stronger, wear resistant material.

Today, roads are almost exclusively built to enable travel by automobile Automobile

An automobile is a wheel [i]ed passenger [i] vehicle [i] that carries its own motor [i]. ... 

 and other wheeled vehicles. In most countries, road transport is the most utilized way to move goods. Also, in most developed countries, roads are formally divided into lanes to ensure the safe and smooth movement of traffic.

Funding

Road building and maintenance is an area of economic activity that remains dominated by the public sector . Roads are typically paid for by tax Tax

A tax is a financial charge or other levy [i] imposed on an individual or a legal entity [i] by a state [i] ... 

es , though some public roads, especially highway Highway

Highway is a term commonly used to designate major road [i]s intended for travel by the public [i] betwe... 

s are funded by tolls.

Driving on the right or the left

Main article: Driving on the left or right Driving on the left or right

In organized traffic [i], vehicles going in opposite directions are separated to a side of the road so ... 

.





Traffic drives on the right or on the left side of the road depending on the country. In countries where traffic drives on the right, traffic sign Traffic sign

Most countries erect signage, known as traffic signs or road signs, at the side of road [i]s to im ... 

s are mostly on the right side of the road, roundabout Roundabout

A roundabout or rotary is a type of road junction [i] at which traffic [i] streams around a cent ... 

s and traffic circle Traffic circle

A traffic circle is an intersection [i] with a circular shape and, usually, a central isla ... 

s go counter-clockwise, and pedestrian Pedestrian

A pedestrian is a person travelling on foot, whether walking [i] or running [i]. ... 

s crossing a two-way road should watch out for traffic from the left first. In countries where traffic drives on the left, the reverse is true.

Traffic flow and road design in both cases are each other's mirror image.

Design

Road design consists of two important technical aspects:
  • geometrical road design
  • structural road design

Besides these two technical sides of the design, environmental issues, planning issues and juridical issues are important.

Construction



Road construction requires the creation of a continuous right-of-way, overcoming geographic obstacles and having grades low enough to permit vehicle or foot travel. Removal of earth and rock by digging or blasting, construction of embankments, bridge Bridge

A bridge is a structure built to span [i] a gorge [i], valley [i], road [i], railroad track [i]... 

s and tunnels Tunnel

A tunnel is an underground passage.... 

, and removal of vegetation are often needed. A variety of road building equipment Engineering vehicle

Engineering vehicles, or construction [i] equipment [i], are heavy-duty vehicles, specially designed for ... 

 is employed in road building.

Once these activities are completed, construction of the pavement can begin. First the native soil Soil

Soil is the collection of natural bodies that form in earthy material on the land surface.... 

, known as the subgrade, is compacted. Weak soils may also be stabilized with additives such as portland cement Portland cement

Portland cement is the most common type of cement [i] in general usage, as it is a basic ingredient of concrete [i] ... 

 and quicklime Calcium oxide

Calcium oxide, commonly known as lime, quicklime or burnt lime, is a widely used chemical compound [i] ... 

, or dug out and replaced with imported soils.

Then a base course consisting of gravel Gravel

Gravel is rock that is of a certain grain size [i] range. ... 

 or crushed stone is usually placed on the subgrade and compacted. On top of the base course is placed a surface course which typically consists of asphalt concrete Asphalt concrete

Asphalt concrete, normally known simply as asphalt [i], is a composite material [i] commonly used for co ... 

 or portland cement concrete. This surface course strengthens the pavement structure by spreading out the vehicle loads applied to the subgrade. It also provides a smooth and high-friction surface for vehicles to drive on.

Modern roads, and indeed many ancient ones, such as those built by the Romans Ancient Rome

Ancient Rome was a civilization [i] that grew out of the city-state [i] of Rome [i], founded in the Italian Peninsula [i] ... 

, feature a convex transverse profile known as superelevation or camber. This is designed to allow water to drain away from the road to its edges. Water is then carried away by gutter Gutter

Water-related meanings
  • A gutter is a long, thin trough, usually one that runs straight.

... 

s to drains placed at intervals. Some roads don't have gutters and water simply drains away to a naturally porous verge, or into ditch Ditch

* For use of the ditch as obstacles for horses, see ditch [i]
... 

es. Modern roads that carry motor traffic also employ camber in curves to aid traffic stability by allowing them to "bank into" the bend to some extent.

On the side of the road there may be retroreflector Retroreflector

A retroreflector is a device that sends light [i] or other radiation back where it came from regardless ... 

s on pegs, rocks or crash barriers, white toward the direction of the traffic on that side of the road, and red toward the other direction. In the road surface there may be cat's eyes: retroreflectors that protrude slightly, but which can be driven over without damage.

Road sign Traffic sign

Most countries erect signage, known as traffic signs or road signs, at the side of road [i]s to im ... 

s are often also made retroreflective Retroreflector

A retroreflector is a device that sends light [i] or other radiation back where it came from regardless ... 

 or even illuminated in rare circumstances. For greater visibility of road signs at daytime, sometimes fluorescence is applied to get very bright colors.

Maintenance




Like all structures, roads deteriorate over time. Deterioration is primarily due to accumulated damage from vehicles, however environmental effects such as frost heaves, thermal cracking and oxidation often contribute. According to a series of experiments carried out in the late 1950s 1950s

The 1950s was the decade spanning the years 1950 to 1959.... 

, called the AASHO Road Test, it was empirically determined that the effective damage done to the road is roughly proportional to the 4th power of axle Axle

An axle is a central shaft for a rotating [i] wheel [i] or gear [i]. ... 

 weight. A typical tractor-trailer weighing 80,000 pounds with 8,000 pounds on the steer axle and 36,000 pounds on both of the tandem axle groups is expected to do 7,800 times more damage than a passenger vehicle with 2,000 pounds on each axle. In most pavement design methodologies trucks are considered to be the sole cause of pavement deterioration.

Pavements are designed for an expected service life. Most European countries have strict standards for road construction that require that most roads should be able to go 30 years or longer between major resurfacings. In the United States new pavements are typically designed for a service life of between 15 and 25 years, depending on the importance of the road. Service life predictions are inherently unreliable due to the difficulty of predicting future traffic and environmental conditions.

Virtually all roads require some form of maintenance before they come to the end of their service life. Maintenance activities can be divided into structural maintenance and functional maintenance, although there is a great deal of overlap. Structural maintenance is maintenance intended to preserve the structural integrity of the pavement, and includes patching pothole Pothole

Potholing [i] can also be the sport of exploring vertical caves as a synonym of caving [i]
... 

s, sealing cracks and overlays. Functional maintenance is maintenance to improve the roadway's function of providing a smooth and safe surface for vehicles to drive on, and includes surface grinding and thin overlays.

Heraldry

Somewhat unusually, in heraldry Heraldry

Heraldry is the practice of designing, displaying, describing and recording coats of arms [i] ... 

, a terrace or champagne , or a compartment Compartment

In heraldry [i], a compartment is a design placed under the shield [i], usually rocks, a grassy m... 

  will be shown as crossed by a "road."

Terminology





  • All-weather road - an unpaved road that is constructed of material that does not create mud during rainfall.
  • arterial road
  • asphalt Asphalt

    Asphalt is a sticky, black and highly viscous [i] liquid or semi-solid that is present in most ... 

  • autobahn Autobahn

    Autobahn is the German [i] word for a major high-speed [i] road [i] restricted to ... 

  • autoroute
  • autostrasse Autostrasse

    The Autostrasse means motorroad in English [i] and exists in some European countrie ... 

  • bitumen Bitumen

    Bitumen is a category of organic [i] liquids that are highly viscous [i], black, stick ... 

  • byway Byway

    A byway is a less-traveled side road, as in:

... 


  • bypass
  • bottleneck Bottleneck

    A bottleneck is literally the neck of a glass or pottery bottle [i]. ... 

  • boulevard Boulevard

    Boulevard has several generally accepted meanings.... 

  • cat's eye
  • chicane Chicane

    A chicane is a sequence of tight serpentine curves in a roadway, used in auto racing [i] and on city str ... 

  • chipseal
  • concrete Concrete

    In construction [i], concrete is a composite [i] building material made from the comb ... 

  • corduroy road
  • corniche
  • cul-de-sac Cul-de-sac

    A cul-de-sac is a dead-end street with only one inlet/outlet.

... 


  • curb
  • curb extension Curb extension

    A curb extension is a traffic calming [i] measure, intended to slow the speed of traffic [i] and increa ... 

  • dirt road Dirt road

    Dirt road is a common term for a type of unpaved road [i]. ... 

  • divided highway
  • expressway Expressway

    An expressway is a divided highway [i], usually 4 lanes or wider. ... 

  • farm to market Farm to Market Road

    A Farm to Market Road or Ranch to Market Road is a state road [i] or county road [i] which serves ... 

  • freeway Freeway

    A freeway is a type of highway [i] that is designed for safer [i] high-speed oper ... 

  • gravel road Gravel road

    A gravel road is a type of unpaved road [i] surfaced with gravel [i] that has been brought to the site f ... 

  • guard rail Guard rail

    A Guard rail is a system designed to keep people or vehicles from straying into dangerous or off-limits ... 

  • green lane
  • hard shoulder Shoulder (road)

    A hard shoulder or simply shoulder is a reserved area alongside the verge of a road [i] or motorway [i] ... 

  • highway Highway

    Highway is a term commonly used to designate major road [i]s intended for travel by the public [i] betwe... 

  • Interchange
  • Intersection
  • Interstate Highway Interstate Highway System

    The Dwight D. Eisenhower [i] National System of Interstate and Defense Highways, commonly called the ... 

  • lane Lane

    The word lane has two meanings:

... 


  • median Central reservation

    On divided roads, including expressway [i]s, motorway [i]s, or autobahn [i]s, the central reservation (British English) [i]... 

  • mountain pass Mountain pass

    In a range of hills, or especially of mountains [i], a pass is a lower point that allows ... 

  • milestone Milestone

    A milestone or kilometre sign is one of a series of number [i]ed markers placed along a road [i] a... 

  • motorway Motorway

    A motorway is both a type of road [i] and a classification or designation. ... 

  • off-ramp Off-Ramp

    Off-Ramp is a fictional [i] character in the DC Comics [i] universe who first appeared in the ... 

  • on-ramp Interchange (road)

    In the field of road transport [i], an interchange is a road junction [i] that typically utiliz ... 

  • Parkway Parkway

    A parkway is a general designation of a type of limited-access highway [i] in some parts of the U.S. [i] ... 

  • pavement
  • pedestrian crossing Pedestrian crossing

    A pedestrian crossing or crosswalk is a designated point on a road [i] at which some means are emp ... 

  • performance Performance

    A performance, in performing arts [i], generally comprises an event in which one group of people behave... 

  • plank road Plank road

    A plank road or puncheon is a dirt [i] path [i] or road [i] covered with a series of plank [i]s, s ... 

  • private highway Private highway

    A private highway is a highway [i] owned and operated for profit by private industry. ... 

  • private road
  • public road
  • public space Public space

    ... 

  • ranch road Farm to Market Road

    A Farm to Market Road or Ranch to Market Road is a state road [i] or county road [i] which serves ... 

  • range road
  • ridge road
  • road junction Junction (road)

    A road junction is a location where vehicular traffic [i] can change between different routes or directi ... 

  • road number
  • road safety Road-traffic safety

    Road-traffic safety aims to reduce the harm resulting from crashes of road vehicle [i]s traveling on pub ... 

  • road surface marking Road surface marking

    Road surface marking is any kind of device or material that is used on a road surface [i] to co ... 

  • roadworks Roadworks

    Roadworks occur when part of the road [i], or in rare cases, the entire road, has to be occupied for wor ... 

  • roundabout intersection Roundabout

    A roundabout or rotary is a type of road junction [i] at which traffic [i] streams around a cent ... 

  • rural route
  • state highway State highway

    State highway, state road or state route can refer to one of three related concepts, two of ... 

  • street Street

    A street is a public [i] parcel of land [i] adjoining building [i]s in an urban [i] ... 

  • toll road
  • traffic calming Traffic calming

    Traffic calming is a set of strategies used by urban planner [i]s and traffic engineer [i] ... 

  • traffic circle Traffic circle

    A traffic circle is an intersection [i] with a circular shape and, usually, a central isla ... 

  • traffic light Traffic light

    A traffic light, also known as traffic signal, stop light, or semaphore [i], ... 

  • traffic sign Traffic sign

    Most countries erect signage, known as traffic signs or road signs, at the side of road [i]s to im ... 

  • Unpaved road - a road without a bound surface layer . Types of unpaved roads include dirt roads and gravel roads. Unpaved roads are much cheaper to construct than paved roads, but may be more expensive to maintain especially when they have high traffic volumes. The cost of operating a vehicle on an unpaved road is also much higher than on a paved road.
  • US highway United States Numbered Highways

    The system of United States Numbered Highways is an integrated system of road [i]s and highway [i]s in ... 

  • winter road Winter road

    Winter roads are temporary highway [i]s carved out of snow and ice.... 

  • 2+1 road 2+1 road

    2+1 road is a specific category of three-lane road [i], consisting of two lanes in one direction and one ... 



See also

  • Inca road system Inca road system

    For the Frank Zappa [i] song, see Inca Roads [i]

... 


  • Line source Line source

    A line source is a source of air, noise, water contamination or electromagnetic radiation that emanates ... 

  • List of roads and highways
  • Logging roads Logging roads

    Logging roads [i] are construced to provide access to the forest for logging [i] and other forest management [i] ... 

  • Public road
  • Road movie
  • Roadway air dispersion model Roadway air dispersion modeling



Roadway air dispersion modeling is the study of air pollutant [i] transport from a roadway or other ... 


  • Roadway noise Roadway noise

    Roadway noise is the collective sound energy emanating from motor vehicle [i]s. ... 

  • Trade route
  • Road safety Road-traffic safety

    Road-traffic safety aims to reduce the harm resulting from crashes of road vehicle [i]s traveling on pub ... 



References

  • Lay MG, Ways of the world. Rutgers University Press, New Brunswick, New Jersey, . ISBN 0-8135-1758-3 .

External links