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Cattle on a dirt road in Paraguay.

Dirt road is a common term for an unpaved road made from the native material of the land surface through which it passes, known to highway engineers as subgrade material. Dirt roads are suitable for vehicles; a narrower path for pedestrians, animals, and possibly small vehicles would be called a dirt track—the distinction is not well-defined. Unpaved roads with a harder surface made by the addition of material such as gravel and aggregate (stones), might be referred to as dirt roads in common usage but are distinguished as improved roads by highway engineers. (Improved unpaved roads include gravel roads, laterite roads, murram roads and macadamized roads).

Compared to a gravel road, a dirt road is not usually graded regularly to produce an enhanced camber to encourage rainwater to drain off the road, and drainage ditches at the sides may be absent. They are unlikely to have embankments through low-lying areas. This leads to greater waterlogging and erosion, and after heavy rain the road may be impassable even to off-road vehicles. For this reason, in some countries, such as Australia and New Zealand, they are known as dry-weather roads.

Dirt road in Switzerland for agricultural use.

Dirt roads take on different characteristics according to the soils and geology where they pass, and may be sandy, stony, rocky or have a bare earth surface, which could be extremely muddy and slippery when wet, and baked hard when dry. They are likely to become impassable after rain. They are common in rural areas of many countries, often very narrow and infrequently used, and are also found in metropolitan areas of many developing countries, where they may also be used as major highways and have considerable width.

Terms similar to dirt road are dry-weather road, earth road, or the "Class Four Highway" designation used in the People's Republic of China. A track, dirt track, or earth track would normally be similar but less suitable for larger vehicles.

Driving on dirt roads[link]

Detail of a dry, loamy road.

While most gravel roads are all-weather roads and can be used by ordinary cars, dirt roads may only be passable by trucks or four-wheel drive vehicles, especially in wet weather, or on rocky or very sandy sections. It is as easy to become bogged in sand as it is in mud; a high clearance under the vehicle may be required for rocky sections.

Driving on dirt roads requires great attention to variations in the surface and it is easier to lose control than on a gravel road. In addition to the hazards already mentioned, and potholes, ruts and ridges, 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 if not shielded
• stones skipping up hitting the car body, lights or windshields when two vehicles pass each other
• dust thrown up from a passing vehicle reducing visibility
• 'washboard' corrugations cause loss of control or damage to vehicle systems such as suspension and steering
• Skidding (loss of traction) on mud after rain.

Dirt road in Brazil

This is an 1880's photo of 653 W Wrightwood (now 655 W Wrightwood) in the Lincoln Park Neighborhood of Chicago, Illinois. Note the wooden sidewalk, dirt road and lack of buildings surrounding the edifice.

See also[link]

• Byway (road)
• Country lane
• Green lane (road)

Wikimedia Commons has media related to: Dirt roads

A dirty baking plate

Dirt is unclean matter, especially when in contact with a person's clothes, skin or possessions when they are said to become dirty. Common types of dirt include:

• dust — a general powder of organic or mineral matter
• filth — foul matter such as excrement
• grime — a black, ingrained dust such as soot
• soil — the mix of clay, sand and humus which lies over the bedrock

Cleaning[link]

When things are dirty they are usually cleaned with solutions like hard surface cleaner and other chemicals; much domestic activity is for this purpose — washing, sweeping and so forth.^[1]

In a commercial setting, a dirty appearance will give a bad impression of a place such as a restaurant. The dirt in such cases may be classified as temporary, permanent and deliberate. Temporary dirt is streaks and detritus that may be removed by ordinary daily cleaning. Permanent dirt is ingrained stains or physical damage which require major renovation to remove. Deliberate dirt is that which results from design decisions such as decor in dirty yellow or grunge styling.^[2]

Disposal[link]

As cities developed, arrangements were made for the disposal of dirt. In Britain, the Public Health Act 1875 required households to place their refuse into a container which could be moved so that it could be carted away. This was the first legal creation of the dustbin.^[3]

Foci[link]

Computer keyboards are especially dirty as, on average, they contain 70 times more microbes than a lavatory seat.^[4]

Health[link]

Modern society is now thought to be excessively clean. Lack of contact with microorganisms in dirt when growing up is hypothesised to be the cause of the epidemic of allergies such as asthma.^[5] The human immune system requires activation and exercise in order to function properly and exposure to dirt may achieve this.^[6] For example, the presence of staphylococcus bacteria on the surface of the skin regulates the inflammation which results from injury.^[7]

People and animals may eat dirt. This is thought to be caused by mineral deficiency and so the condition is commonly seen in pregnant women.

Neurosis[link]

People may become obsessed by dirt and engage in fantasies and compulsive behaviour about it, such as making and eating mud pies.^[8] The source of such thinking may be genetic, as the emotion of disgust is common and a location for it in the brain has been proposed.^[9]

Exhibitions and studies[link]

A season of artworks and exhibits on the theme of dirt was sponsored by the Wellcome Trust in 2011. The centrepiece was an exhibition at the Wellcome Collection showing pictures and histories of notable dirt such as the great dust heaps at Euston and King's Cross in the 19th century and the Fresh Kills landfill which was once the world's largest.^[10]

References[link]

Further reading[link]

• Terence McLaughlin (1971), Dirt: a social history as seen through the uses and abuses of dirt, Stein and Day, ISBN 978-0-8128-1412-5 
• Pamela Janet Wood (2005), Dirt: filth and decay in a new world arcadia, Auckland University Press, ISBN 978-1-86940-348-5 
• Ben Campkin, Rosie Cox (2007), Dirt: new geographies of cleanliness and contamination, I.B. Tauris, ISBN 978-1-84511-672-9 
• Virginia Smith et al. (2011), Dirt: The Filthy Reality of Everyday Life, Profile Books Limited, ISBN 978-1-84668-479-1 

External links[link]

• Dirt season at the Wellcome Collection

A road is a route, thoroughfare or way that supports travel by a means of conveyance.

Definitions[link]

For purposes of international statistical comparison, the Organisation for Economic Co-operation and Development (OECD) defines a road as "a line of communication (travelled way) using a stabilized base other than rails or air strips open to public traffic, primarily for the use of road motor vehicles running on their own wheels," which includes "bridges, tunnels, supporting structures, junctions, crossings, interchanges, and toll roads, but not cycle paths."^[1] In urban areas roads may diverge through a city or village and be named as streets, serving a dual function as urban space easement and route.^[2] Modern roads are normally smoothed, paved, or otherwise prepared to allow easy travel.^[3] Historically many roads were simply recognizable routes without any formal construction or maintenance.^[4]

United States[link]

In the United States, laws distinguish between public roads, which are open to public use, and private roads, which are privately controlled.^[5]

United Kingdom[link]

In the United Kingdom there is some ambiguity between the terms highway and road. The Highway code details rules for "road users".^[6] For the purposes of the English law, Highways Act 1980, which covers England and Wales but not Scotland or Northern Ireland, the term road is defined to be "any length of highway or of any other road to which the public has access, and includes bridges over which a road passes."^[7] This includes footpaths, bridleways and cycle tracks, and also road and driveways on private land and many car parks.^[8] Vehicle Excise Duty, a road use tax, is payable on some vehicles used on the public road.^[8]

The definition of a road depends on the definition of a highway, however there is no formal definition for a highway in the relevant Act. A 1984 ruling said "the land over which a public right of way exists is known as a highway; and although most highways have been made up into roads, and most easements of way exist over footpaths, the presence or absence of a made road has nothing to do with the distinction.^[9][10] Another legal view is that while a highway historically included footpaths, bridleways, driftways, etc., it can now be used to mean those ways that allow the movement of motor-vehicles, and the term rights of way can be used to cover the wider usage.^[11]

Historical road construction[link]

The Porta Rosa is a Greek street dating from the 3rd to 4th century BC in Velia, Italy with a paved surface and gutters.

A paved Roman road in Pompeii, Italy

The assertion that the first pathways were the trails made by animals has not been universally accepted, since in many cases animals do not follow constant paths.^[4] Others believe that some roads originated from following animal trails.^[12][13] The Icknield Way is given as an example of this type of road origination, where man and animal both selected the same natural line.^[14] By about 10,000 BC, rough pathways were used by human travelers.^[4]

• The world's oldest known paved road was laid in Egypt some time between 2600 and 2200 BC.^[15]

• Stone-paved streets are found in the city of Ur in the Middle East dating back to 4000 BC.^[4]

• Corduroy roads (log roads) are found dating to 4000 BC in Glastonbury, England.^[4]

• The timber trackway; Sweet Track causeway in England, is one of the oldest engineered roads discovered and the oldest timber trackway discovered in Northern Europe. Built in winter 3807 BC or spring 3806 BC, tree-ring dating (Dendrochronology) enabled very precise dating. It has been claimed to be the oldest road in the world.^[16][17]

• Brick-paved streets were used in India as early as 3000 BC .^[4]

• In 500 BC, Darius I the Great started an extensive road system for Persia (Iran), including the famous Royal Road, which was one of the finest highways of its time.^[18] The road remained in use after Roman times.

• In ancient times, transport by river was far easier and faster than transport by road,^[17] especially considering the cost of road construction and the difference in carrying capacity between carts and river barges. A hybrid of road transport and ship transport beginning in about 1740 is the horse-drawn boat in which the horse follows a cleared path along the river bank.^[19][20]

• From about 312 BC, the Roman Empire built straight^[21] strong stone Roman roads throughout Europe and North Africa, in support of its military campaigns. At its peak the Roman Empire was connected by 29 major roads moving out from Rome and covering 78,000 kilometers or 52,964 Roman miles of paved roads.^[17]

• In the 8th century AD, many roads were built throughout the Arab Empire. The most sophisticated roads were those in Baghdad, Iraq, which were paved with tar. Tar was derived from petroleum, accessed from oil fields in the region, through the chemical process of destructive distillation.^[22]

• The Highways Act 1555 in Britain transferred responsibility for maintaining roads from government to local parishes.^[17] This resulted in a poor and variable state of roads. To remedy this, the first of the "Turnpike trusts" was established around 1706, to build good roads and collect tolls from passing vehicles. Eventually there were approximately 1,100 trusts in Britain and some 36,800 km (22,870 miles) of engineered roads.^[17] The Rebecca Riots in Carmarthenshire and Rhayader from 1839 to 1844 contributed to a Royal Commission that led to the demise of the system in 1844,^[23] which coincided with the development of the UK railway system.

Design[link]

Structural road design is the science of designing a road for its environment in order to extend its longevity and reduce maintenance. The Shell pavement design method is used in many countries for the design of new asphalt roads.

Construction[link]

A road being torn up.

Surveyor at work with a leveling instrument.

Asphalt layer and roller

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.^{[24] (pg15)} and may be required to meet standards set by law^[25] or official guidelines.^[26] The process is often begun with the removal of earth and rock by digging or blasting, construction of embankments, bridges and tunnels, and removal of vegetation (this may involve deforestation) and followed by the laying of pavement material. A variety of road building equipment is employed in road building.^[27][28]

After design, approval, planning, legal and environmental considerations have been addressed alignment of the road is set out by a surveyor.^[21] The Radii and gradient are designed and staked out to best suit the natural ground levels and minimize the amount of cut and fill.^{[26] (page34)} Great care is taken to preserve reference Benchmarks ^{[26] (page59)}

Roads are designed and built for primary use by vehicular and pedestrian traffic. Storm drainage and environmental considerations are a major concern. Erosion and sediment controls are constructed to prevent detrimental effects. Drainage lines are laid with sealed joints in the road easement with runoff coefficients and characteristics adequate for the land zoning and storm water system. Drainage systems must be capable of carrying the ultimate design flow from the upstream catchment with approval for the outfall from the appropriate authority to a watercourse, creek, river or the sea for drainage discharge.^{[26] (page38 to 40)}

Road construction on Marquette Avenue in Minneapolis, Minnesota, United States

A borrow pit (source for obtaining fill, gravel, and rock) and a water source should be located near or in reasonable distance to the road construction site. Approval from local authorities may be required to draw water or for working (crushing and screening) of materials for construction needs. The top soil and vegetation is removed from the borrow pit and stockpiled for subsequent rehabilitation of the extraction area. Side slopes in the excavation area not steeper than one vertical to two horizontal for safety reasons.^{[26] (page 53 to 56 )}

Old road surfaces, fences, and buildings may need to be removed before construction can begin. Trees in the road construction area may be marked for retention. These protected trees should not have the topsoil within the area of the tree's drip line removed and the area should be kept clear of construction material and equipment. Compensation or replacement may be required if a protected tree is damaged. Much of the vegetation may be mulched and put aside for use during reinstatement. The topsoil is usually stripped and stockpiled nearby for rehabilitation of newly constructed embankments along the road. Stumps and roots are removed and holes filled as required before the earthwork begins. Final rehabilitation after road construction is completed will include seeding, planting, watering and other activities to reinstate the area to be consistent with the untouched surrounding areas.^{[26] (page 66 to 67 )}

Processes during earthwork include excavation, removal of material to spoil, filling, compacting, construction and trimming. If rock or other unsuitable material is discovered it is removed, moisture content is managed and replaced with standard fill compacted to 90% relative compaction. Generally blasting of rock is discouraged in the road bed. When a depression must be filled to come up to the road grade the native bed is compacted after the topsoil has been removed. The fill is made by the "compacted layer method" where a layer of fill is spread then compacted to specifications, the process is repeated until the desired grade is reached.^{[26] (page 68 to 69 )}.

Line marking

General fill material should be free of organics, meet minimum California bearing ratio (CBR) results and have a low plasticity index. The lower fill generally comprises sand or a sand-rich mixture with fine gravel, which acts as an inhibitor to the growth of plants or other vegetable matter. The compacted fill also serves as lower-stratum drainage. Select second fill (sieved) should be composed of gravel, decomposed rock or broken rock below a specified Particle size and be free of large lumps of clay. Sand clay fill may also be used. The road bed must be "proof rolled" after each layer of fill is compacted. If a roller passes over an area without creating visible deformation or spring the section is deemed to comply.^{[26] (page 70 to 72 )}

Geosynthetics such as geotextiles, geogrids and geocells are frequently used in the various pavement layers to improve road quality. Geosynthetics perform four main functions in roads: separation, reinforcement, filtration and drainage; which increase the pavement performance, reduce construction costs and decrease maintenance.^[29]

The completed road way is finished by paving or left with a gravel or other natural surface. The type of road surface is dependent on economic factors and expected usage. Safety improvements like Traffic signs, Crash barriers, Raised pavement markers, and other forms of Road surface marking are installed.

According to a May 2009 report by the American Association of State Highway and Transportation Officials (AASHTO) and TRIP—a national transportation research organization—driving on rough roads costs the average American motorist approximately $400 a year in extra vehicle operating costs. Drivers living in urban areas with populations more than 250,000 are paying upwards of $750 more annually because of accelerated vehicle deterioration, increased maintenance, additional fuel consumption, and tire wear caused by poor road conditions.

When a single carriageway road is converted into dual carriageway by building a second separate carriageway alongside the first, it is usually referred to as duplication,^[30] twinning or doubling. The original carriageway is changed from two-way to become one-way, while the new carriageway is one-way in the opposite direction. In the same way as converting railway lines from single track to double track, the new carriageway is not always constructed directly alongside the existing carriageway.

Maintenance[link]

"Road works ahead" sign, typically used in Europe

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.^[31] According to a series of experiments carried out in the late 1950s, called the AASHO Road Test, it was empirically determined that the effective damage done to the road is roughly proportional to the Fourth power of axle weight.^[32] A typical tractor-trailer weighing 80,000 pounds (36.287 t) with 8,000 pounds (3.629 t) on the steer axle and 36,000 pounds (16.329 t) on both of the tandem axle groups is expected to do 7,800 times more damage than a passenger vehicle with 2,000 pounds (0.907 t) on each axle. Potholes on roads are caused by rain damage and vehicle braking or related construction works.

Manual road repair taking place in Howrah, India.

Pavements are designed for an expected service life or design life. In some UK countries the standard design life is 40 years for new bitumen and concrete pavement. Maintenance is considered in the whole life cost of the road with service at 10, 20 and 30 year milestones.^[33] Roads can be and are designed for a variety of lives (8-, 15-, 30-, and 60-year designs). When pavement lasts longer than its intended life, it may have been overbuilt, and the original costs may have been too high. When a pavement fails before its intended design life, the owner may have excessive repair and rehabilitation costs. Many concrete pavements built since the 1950s have significantly outlived their intended design lives.^[34] Some roads like Chicago, Illinois's "Wacker Drive", a major two-level viaduct in downtown area are being rebuilt with a designed service life of 100 years.^[35]

Virtually all roads require some form of maintenance before they come to the end of their service life. Pro-active agencies use pavement management techniques to continually monitor road conditions and schedule preventive maintenance treatments as needed to prolong the lifespan of their roads. Technically advanced agencies monitor the road network surface condition with sophisticated equipment such as laser/inertial Profilometers. These measurements include road curvature, cross slope, asperity, roughness, rutting and texture (roads). This data is fed into a pavement management system, which recommends the best maintenance or construction treatment to correct the damage that has occurred.

Maintenance treatments for asphalt concrete generally include crack sealing, surface rejuvenating, fog sealing, micro-milling and surface treatments. Thin surfacing preserves, protects and improves the functional condition of the road while reducing the need for routing maintenance, leading to extended service life without increasing structural capacity.^[36]

Failure to maintain roads properly can create significant costs to society, in a 2009 report released by the American Association of State Highway and Transportation Officials (USA) about 50% of the roads in the USA are in bad condition with urban areas worse. The report estimates that urban drivers pay an average of $746/year on vehicle repairs while the average US motorist pays about $335/year. In contrast, the average motorist pays about $171/year in road maintenance taxes (based on 600 gallons/year and $0.285/gallon tax).

Slab Stabilization[link]

Distress and serviceability loss on concrete roads can be caused by loss of support due to voids beneath the concrete pavement slabs. The voids usually occur near cracks or joints due to surface water infiltration. The most common causes of voids are pumping, consolidation, subgrade failure and bridge approach failure. Slab stabilization is a non-destructive method of solving this problem and is usually employed with other Concrete Pavement Restoration (CPR) methods including patching and diamond grinding. The technique restores support to concrete slabs by filing small voids that develop underneath the concrete slab at joints, cracks or the pavement edge. The process consists of pumping a cementitous grout or polyurethane mixture through holes drilled through the slab. The grout can fill small voids beneath the slab and/or sub-base. The grout also displaces free water and helps keep water from saturating and weakening support under the joints and slab edge after stabilization is complete. The three steps for this method after finding the voids are locating and drilling holes, grout injection and post-testing the stabilized slabs.

Slab stabilization does not correct depressions, increase the design structural capacity, stop erosion or eliminate faulting. It does, however, restore the slab support, therefore, decreasing deflections under the load. Stabilization should only be performed at joints and cracks where loss of support exists. Visual inspection is the simplest manner to find voids. Signs that repair is needed are transverse joint faulting, corner breaks and shoulder drop off and lines at or near joints and cracks. Deflection testing is another common procedure utilized to locate voids. It is recommended to do this testing at night as during cooler temperatures, joints open, aggregate interlock diminishes and load deflections are at their highest.

Testing[link]

Ground penetrating radar pulses electromagnetic waves into the pavement and measures and graphically displays the reflected signal. This can reveal voids and other defects.

The epoxy/core test, detects voids by visual and mechanical methods. It consists of drilling a 25 to 50 millimeter hole through the pavement into the sub-base with a dry-bit roto-hammer. Next, a two-part epoxy is poured into the hole—dyed for visual clarity. Once the epoxy hardens, technicians drill through the hole. If a void is present, the epoxy will stick to the core and provide physical evidence.

Common stabilization materials include pozzolan-cement grout and polyurethane. The requirements for slab stabilization are strength and the ability to flow into or expand to fill small voids. Colloidal mixing equipment is necessary to use the pozzolan-cement grouts. The contractor must place the grout using a positive-displacement injection pump or a non-pulsing progressive cavity pump. A drill is also necessary but it must produce a clean hole with no surface spalling or breakouts. The injection devices must include a grout packer capable of sealing the hole. The injection device must also have a return hose or a fast-control reverse switch, in case workers detect slab movement on the uplift gauge. The uplift beam helps to monitor the slab deflection and has to have sensitive dial gauges.^[37][38]

Joint Sealing[link]

Also called joint and crack repair, this method’s purpose is to minimize infiltration of surface water and incompressible material into the joint system. Joint sealants are also used to reduce dowel bar corrosion in Concrete Pavement Restoration (CPR) techniques. Successful resealing consists of old sealant removal, shaping and cleaning the reservoir, installing the backer rod and installing the sealant. Sawing, manual removal, plowing and cutting are methods used to remove the old sealant. Saws are used to shape the reservoir. When cleaning the reservoir, no dust, dirt or traces of old sealant should remain. Thus, it is recommended to water wash, sand-blast and then air blow to remove any sand, dirt or dust. The backer rod installation requires a double-wheeled, steel roller to insert the rod to the desired depth. After inserting the backer rod, the sealant is placed into the joint. There are various materials to choose for this method including hot pour bituminous liquid, silicone and preformed compression seals.

^{[37][39][40][41]}

Safety considerations[link]

Pedestrian crossing, line markings and street furniture.

Careful design and construction of roads can increase Road traffic safety and reduce the harm (deaths, injuries, and property damage) on the highway system from traffic collisions.

On neighborhood roads traffic calming, safety barriers, pedestrian crossings and cycle lanes can all protect pedestrians and cyclists.

Lane markers in some countries and states are marked with Cat's eyes or Botts dots, bright reflectors that do not fade like paint. Botts dots are not used where it is icy in the winter, because frost and snowplows can break the glue that holds them to the road, although they can be embedded in short, shallow trenches carved in the roadway, as is done in the mountainous regions of California.

For major roads risk can be reduced by providing limited access from properties and local roads, grade separated junctions and median dividers between opposite-direction traffic to reduce likelihood of head-on collisions.

The placement of energy attenuation devices (e.g. guardrails, wide grassy areas, sand barrels) is also common. Some road fixtures such as road signs and fire hydrants are designed to collapse on impact. Light poles are designed to break at the base rather than violently stop a car that hits them. Highway authorities may also remove larger trees from the immediate vicinity of the road.

Environmental performance[link]

Air pollution along Pasadena Highway in Los Angeles, United States

Careful design and construction of a road can reduce any negative environmental impacts.

Water management systems can be used to reduce the effect of pollutants from roads.^{[citation needed]} Rainwater and snowmelt running off of roads tends to pick up gasoline, motor oil, heavy metals, trash and other pollutants and result in Water pollution. Road runoff is a major source of nickel, copper, zinc, cadmium, lead and polycyclic aromatic hydrocarbons (PAHs), which are created as combustion byproducts of gasoline and other fossil fuels.^[42] De-icing chemicals and sand can run off into roadsides, contaminate groundwater and pollute surface waters;^[43] and road salts can be toxic to sensitive plants and animals.^[44] Sand applied to icy roads can be ground up by traffic into fine particulates and contribute to air pollution. Sand can alter stream bed environments, causing stress for the plants and animals that live there.^{[citation needed]}

Roads are a chief source of environmental noise generation. In the early 1970s it was recognized that design of roads can be conducted to influence and minimize noise generation.^[45] Noise barriers are used to reduce Noise pollution, in particular where roads are located close to built-up areas. Regulations can restrict the use of Engine braking.

Motor vehicle emissions contribute air pollution. Concentrations of air pollutants and adverse respiratory health effects are greater near the road than at some distance away from the road.^[46] Road dust kicked up by vehicles may trigger allergic reactions.^[47]

Terminology[link]

The A22(T) with line markings near Summer Hill, East Sussex, England, United Kingdom

Road with guard rails in Kaluga Oblast, Russia

Road with traffic signs in the outskirts of Bern, Switzerland

Highway 401, a route with a collector / express setup.

The wide Coastal Road in the Philippines now called the Manila Cavite Expressway

Road in the Jujuy Province Argentina

• Alignment - the route of the road, defined as a series of horizontal tangents and curves.
• Adverse camber - where a road slopes towards the outside of a bend, increasing the likelihood that vehicles travelling at speed will skid or topple. Usually only a temporary situation during road maintenance.
• All-weather road - Unpaved road that is constructed of a material that does not create mud during rainfall.
• Banked turn
• Camber or Crown - the slope of the road surface downwards away from the centre of the road, so that surface water can flow freely to the edge of the carriageway, or on bends angling of the surface to lean traffic 'into the bend' reducing the chance of a skid.
• Cant - superelevation
• Cross slope The slope of the pavement, expressed as units of rise per unit of run, or as a percentage.
• Grade - longitudinal slope
• Belisha Beacon - an orange globe, lit at night, used to highlight a pedestrian crossing.
• Bollard - Rigid posts that can be arranged in a line to close a road or path to vehicles above a certain width
• Byway - Highway over which the public have a right to travel for vehicular and other kinds of traffic, but is used mainly as a footpath or bridleway
• Bypass Road that avoids or "bypasses" a built-up area, town, or village
• Bottleneck - Section of a road with a carrying capacity substantially below that of other sections of the same road
• Botts' dots - Non-reflective raised pavement marker used on roads
• Cat's eye - reflective raised pavement marker used on roads
• Central reservation - On dual carriageway roads, including controlled-access highways, divided highways and many limited-access roads, the central reservation (British English), median (North American English), median strip (North American English and Australian English), neutral ground [Louisiana English] or central nature strip (Australian English) - Area that separates opposing lanes of traffic
• Chicane - Sequence of tight serpentine curves (usually an S-shape curve or a bus stop)
• Chipseal - Road surface composed of a thin layer of crushed stone 'chips' and asphalt emulsion. It seals the surface and protects it from weather, but provides no structural strength. It is cheaper than asphalt concrete or concrete. In the U.S. it is usually only used on low volume rural roads
• Corniche - Road on the side of a cliff or mountain, with the ground rising on one side and falling away on the other
• Curb (kerb) - A raised edge at the side of the roadway.
• Curb extension - (also kerb extension, bulb-out, nib, elephant ear, curb bulge and blister) Traffic calming measure, intended to slow the speed of traffic and increase driver awareness, particularly in built-up and residential neighborhoods.
• Drainage gradient
• Farm-to-market road - a state road or county road that connects rural or agricultural areas to market towns.
• Fork - (literally "fork in the road") Type of intersection where a road splits
• Green lane - (UK) Unsurfaced road, may be so infrequently used that vegetation colonises freely, hence 'green'. Many green lanes are ancient routes that have existed for millennia.
• Guide rail - Prevents vehicles from veering off the road into oncoming traffic, crashing against solid objects or falling from a road. Also called a guard rail or traffic barrier.
• Gutter (UK) - a drainage channel usually at the edge of the road or along a median.
• Interstate Highway System (United States) - System of Interstate and Defense Highways
• Layby (Pullout, pull-off) - A paved area beside a main road where cars can stop temporarily to let another car pass.
• Loose chippings - the hazard of stone chippings that have come loose
• Median - On dual carriageway roads, including controlled-access highways, divided highways and many limited-access roads, the central reservation (British English), median (North American English), median strip (North American English and Australian English), neutral ground [Louisiana English] or central nature strip (Australian English) - Area that separates opposing lanes of traffic
• Mountain pass - A relatively low level route through a range of mountains
• Milestone - One of a series of numbered markers placed along a road, often at regular intervals, showing the distance to destinations.
• National Highway - Road built and maintained by a national authority.
• Pavement - The road regarded as a geoconstruction. In the UK the term is road surface and the pavement is a pedestrian walkway alongside the road.
• Pedestrian crossing - Designated point on a road where road marking or other means helps pedestrians cross safely
• Pelican crossing - (officially Pelicon crossing) UK a PEdestrian LIght CONtrolled crossing.
• Private highway - Highway owned and operated for profit by private industry
• Private road - Road owned and maintained by a private individual, organization, or company rather than by a government
• Profile - the vertical alignment of a road, expressed as a series of grades, connected by parabolic curves.
• Public space - Place where anyone has a right to come without being excluded because of economic or social conditions
• Ranch road - U.S. road that connects rural and agricultural areas to market towns
• Road number - Often assigned to identify a stretch of public roads— often dependent on the type of road, with numbers differentiating between interstates, motorways, arterial thoroughfares, etc.
• Road-traffic safety - Process to reduce the harm (deaths, injuries, and property damage) that result from vehicle crashes on public roads
• Roadworks - Part or all of the road is occupied for work or maintenance
• Roughness - Deviations from a true planar pavement surface, which affects vehicle suspension deflection, dynamic loading, ride quality, surface drainage and winter operations. Roughness have wavelengths ranging from 500 mm up to some 40 m. The upper limit may be as high as 350 m when considering motion sickness aspects; motion sickness is generated by motion with down to 0.1 Hz frequency; in an ambulance car driving 35 m/s (126 km/h), waves with up to 350 m will excite motion sickness.
• Roundabout UK a road junction where typically three or more roads are joined by a circular section of road. Traffic 'on the roundabout' has priority over traffic on approach roads, unless indicated otherwise. In countrys where traffic drives on the left the roundabout is travelled in a clockwise direction. Also known as an island in parts of the UK.
• Shoulder (also hard shoulder) - A clear, level area to the side of the roadway available for stopping if needed.
• State highway - Road numbered by the state, falling below numbered national highways (like U.S. Routes) in the hierarchy or a road maintained by the state, including nationally-numbered highways
• Traffic - Pedestrians, ridden or herded animals, vehicles, bicycles, and other conveyances using any road for purposes of travel. ^[48].
• Texture (roads) - Deviations from a true planar pavement surface, which affects the interaction between road and tire. Microtexture have wavelengths below 0.5 mm, Macrotexture below 50 mm and Megatexture below 500 mm.
• Traffic calming - Set of strategies used by urban planners and traffic engineers to slow down or reduce motor vehicle traffic, thereby improving safety for pedestrians and bicyclists and improving the environment for residents
• Traffic island - UK a small raised area used to help define the traffic flow, which may also act as a refuge for pedestrians crossing the carriageway or a location for signs, barriers or lights—a synonym for roundabout in some parts of the UK
• Traffic light - Also known as a traffic signal, stop light, stop-and-go lights—a signaling device at a road intersection, pedestrian crossing, or other location that assigns right of way to different approaches to an intersection
• Zebra crossing (UK) - a pedestrian crossing marked by black and white stripes on the carriageway

Regulation[link]

Right- and left-hand traffic[link]

Traffic flows on the right or on the left side of the road depending on the country.^[49] In countries where traffic flows on the right, traffic signs are mostly on the right side of the road, roundabouts and traffic circles go counter-clockwise/anti-clockwise, and pedestrians crossing a two-way road should watch out for traffic from the left first.^[50] In countries where traffic flows on the left, the reverse is true.

About 33% of the world by population drive on the left, and 67% keep right. By road distances, about 28% drive on the left, and 72% on the right,^[51] even though originally most traffic drove on the left worldwide.^[52]

Economics[link]

A city street in Mumbai, India with left-hand traffic.

Transport economics is used to understand both the relationship between the transport system and the wider economy and the complex network effects when there are multiple paths and competing modes for both personal and freight (road/rail/air/ferry) and where Induced demand can result in increased on decreased transport levels when road provision is increased by building new roads or decreased (for example California State Route 480). Roads are generally built and maintained by the public sector using taxation although implementation may be through private contractors).^[53][54] or occasionally using road tolls.^[55]

Public-private partnerships are a way for our communities to address the rising cost by injecting private funds into our infrastructure. There are four main ones:^[56]

• design/build
• design/build/operate/maintain
• design/build/finance/operate
• build/own/operate

Economics and society depend heavily on efficient roads. In the European Union (EU) 44% of all goods are moved by trucks over roads and 85% of all persons are transported by cars, buses or coaches on roads.^[57] The term was also commonly used to refer to roadsteads, waterways that lent themselves to use by shipping.

Construction costs[link]

According to the New York State Thruway Authority,^[58] some sample per-mile costs to construct multi-lane roads in several US northeastern states were:

• Connecticut Turnpike — $3,449,000 per mile
• New Jersey Turnpike — $2,200,000 per mile
• Pennsylvania Turnpike (Delaware Extension) — $1,970,000 per mile
• Northern Indiana Toll Road — $1,790,000 per mile
• Garden State Parkway — $1,720,000 per mile
• Massachusetts Turnpike — $1,600,000 per mile
• Thruway, New York to Pennsylvania Line — $1,547,000 per mile
• Ohio Turnpike — $1,352,000 per mile
• Pennsylvania Turnpike (early construction) — $736,000 per mile

Statistics[link]

The United States has the largest network of roads of any country with 4,050,717 miles (6,518,997 km) as of 2009.^[59] The People's Republic of China is second with 3,583,715 kilometres (2,226,817 mi) of road (2007) See List of countries by road network size. The Republic of India has the third largest road system in the world with 3,383,344 kilometres (2,102,312 mi) (2002). When looking only at expressways the National Trunk Highway System (NTHS) in People's Republic of China has a total length of 45,000 kilometres (28,000 mi) at the end of 2006, and 60,300 km at the end of 2008, second only to the United States with 90,000 kilometres (56,000 mi) in 2005.^[60][61]

Many human settlements are not reachable by road alone. Road vehicles must be carried by boat or ferry to islands, and some locations are intentionally car-free. Even on the mainland, some settlements have no roads connecting with the main continental network, due to natural obstacles like mountains or wetlands, remoteness, or general expense. Unpaved roads or lack of roads are more common in developing countries, though even large cities like Iquitos in Peru and Juneau, Alaska in the United States are disconnected.

See also[link]

References[link]

This biographical article needs additional citations for verification. Please help by adding reliable sources. Contentious material about living persons that is unsourced or poorly sourced must be removed immediately, especially if potentially libelous or harmful. (March 2008)

Jason Aldean
Background information
Birth name	Jason Aldine Williams[1]
Born	(1977-02-28) February 28, 1977 (age 35)[2] Macon, Georgia, USA[2]
Genres	Country, country-rock
Occupations	Singer
Instruments	Vocals, guitar
Years active	2005–present
Labels	Capitol Nashville Broken Bow
Associated acts	Kelly Clarkson Colt Ford Miranda Lambert, Ludacris, Brantley Gilbert Lionel Richie
Website	JasonAldean.com

Jason Aldine Williams (born February 28, 1977 in Macon, Georgia) is an American country music singer, known professionally as Jason Aldean. Since 2005, Aldean has recorded for Broken Bow Records, an independent record label for which he has released four albums and fifteen singles. His 2005 self-titled debut and 2009 album Wide Open are both certified platinum by the Recording Industry Association of America (RIAA), while 2007's Relentless is certified gold. Of his singles, seven have reached the number one position on the Hot Country Songs charts: "Why", "She's Country", "Big Green Tractor", "The Truth", "Don't You Wanna Stay" (a duet with Kelly Clarkson), "Dirt Road Anthem", and "Fly Over States." Eight more have reached top ten on the same chart.

Early life[link]

Aldean's parents, Barry and Debbie, divorced when he was three. He was raised by his mother, mainly in Macon, Georgia, where he went to high school at Windsor Academy. During the summer he would spend time with his father in Homestead, Florida.

Before going to work during the day, his dad would map out guitar chords on notebook paper to show Jason where to place his fingers to play the chords. Jason sat and practiced all day while his dad was at work. When his dad got home, he got out his own guitar and they played together. Soon, after hearing a song only a few times, he could play it. His early favorites included George Strait's "The Cowboy Rides Away", Hank Williams Jr.'s "The Blues Man", and Alabama's "My Home's in Alabama". Both parents encouraged young Jason as he progressed musically. From age 14, after watching the country-music awards on TV, he wanted to perform on stage. With his mother's help, he performed at the local VFW hall in Macon, Georgia. He sang John Anderson's song "Seminole Wind" and Tracy Lawrence's "Sticks and Stones". He would later say that the entire audience — all ten — applauded, and that he almost had to be dragged off the stage because he was hooked on performing. He began performing at area talent contests and local fairs. At 15, he joined the "house band" at Georgia nightspot Nashville South.

Personal life[link]

Aldean married his high school sweetheart, Jessica, and they now have two daughters, Keeley and Kendyl. Aldean married Jessica on August 4, 2001.^[3]

Musical career[link]

After high school, with his father's help, Aldean and his band performed in college towns in Florida, Alabama, and Georgia, and then further up the southeastern seaboard. With one of the band's members, Justin Weaver, Aldean began writing songs. In 1998 he performed his original songs at a showcase staged by Atlanta nightclub The Buckboard. He was approached by Michael Knox, then of the Warner-Chappell song-publishing company.^[4] After signing with Warner-Chappell, Aldean moved to Nashville on November 1, 1998, at age 21.

A month after moving to Nashville, Aldean was offered a recording contract but was subsequently dropped. He signed with another label but again was dropped in 2000 for postponing his recording sessions repeatedly. Various showcases failed to bring him a contract. The last straw was an attempt at the Wildhorse Saloon where the promised label talent scouts never even showed up. Finally, Lawrence Mathis spotted Jason at one of the showcases at The Wildhorse Saloon in Nashville. Mathis signed as Aldean's first manager. Still frustrated and discouraged with his struggling career, Aldean gave himself six months before planning to leave Nashville and return home to Georgia. Then five weeks later, he was offered a deal from Broken Bow Records in Nashville. Shortly after the release of his first album, Jason picked up his new (and current) agent, Kevin Neal. And while recording Relentless, Jason moved to Clarence Spalding and Spalding Entertainment for management.

[edit] Jason Aldean (2005-2006)

Aldean's first single, "Hicktown", was released in early 2005.^[4] It served as the lead-off to his album Jason Aldean, and reached a peak of #10 on the Billboard Hot Country Songs charts. The album also produced his first Number One hit in "Why", as well as the #4-peaking "Amarillo Sky", which had previously been a non-charting single in 2002 for McBride & the Ride. Amarillo Sky earned a 2006 ACM nomination for song of the year and video of the year. Jason Aldean earned the title of "Top New Male Vocalist" at the 2006 Academy of Country Music Awards. Jason Aldean has sold over one million copies in the United States, and was certified platinum by the RIAA in 2007.

[edit] Relentless (2007-2008)

Aldean spent most of January 2007 in the studio with producer Michael Knox to finish his second album, Relentless.^[4] This album was released on May 29, 2007, and at Wal-Mart, it was released with a Limited Edition CMT Pick DVD that includes performances from Jason Aldean. The album's lead-off single, "Johnny Cash", was originally recorded by Tracy Byrd and peaked at #6 when Aldean released it. Its followup, "Laughed Until We Cried", has become his fifth consecutive Top Ten hit. Relentless has also been certified gold by the RIAA, and its title track was released as its third single. The song has also been Aldean's lowest charting single in both the U.S. and Canada, failing to reach Top Ten on the country charts.

[edit] Wide Open (2009-2010)

Aldean released a seventh single titled "She's Country" to radio on December 1, 2008. It is the first single from his third album Wide Open which was released on April 7, 2009. The single debuted at #51 on the Hot Country Songs chart in late-November 2008. His seventh consecutive Top 40 hit on the country charts, it is also his first Top 40 hit on the Billboard Hot 100, and became his second number-one hit, and his first since "Why" in May 2006. The next single, the David Lee Murphy-Jim Collins co-write "Big Green Tractor," became Aldean's third Number One hit. Wide Open debuted at #2 on the Top Country Albums chart. "The Truth" became the album's third consecutive Number One hit in January 2010, with "Crazy Town" being the album's fourth single, peaking at #2 on the country charts.

Jason Aldean performed with Bryan Adams on an episode of CMT Crossroads in the beginning of May, and the episode premiered on June 26, 2009.^[5] In an interview with Shave Magazine, Jason explained that working with Bryan on Crossroads "was great. He was a lot of fun." But the real highlight for Jason was working with Randy Owen. "I am a big fan of Alabama so I got a chance to work with Randy Owen on this album (it didn’t make the album but it eventually made a bonus track). It was really cool. Alabama were like ‘The Beatles’ for me so working with him was definitely one of the highlights. I mean, both of those guys were really cool moments, but, if I had to pick one highlight, it would be working with Randy this year."^[6]

A live DVD titled Wide Open Live & More was released on August 25, 2009.

At the 2010 CMT music Awards Jason Aldean picked up 3 nominations in Video of the Year and Male Video of the Year for "The Truth", as well as collaborative video of the year and CMT performance of the year for his performance of "Heaven" with Bryan Adams.^[7]

[edit] My Kinda Party (2010-2012)

Aldean released a new single in August 2010, "My Kinda Party," which entered the Hot Country Songs chart at #41, which is the lead-off single from his album of the same name, released on November 2, 2010.^[8] It marks as Aldean's tenth top 10 country hit. He also collaborated with Kelly Clarkson on the intimate duet "Don't You Wanna Stay". Aldean and Clarkson's performance on November 10, 2010 at the CMA Awards received positive recognition, and debuted at #59 on Billboard's Hot Country Songs chart from unsolicited airplay for the week of November 20, 2010. In March 2011, "Don't You Wanna Stay" became Aldean's fifth number one hit.

In early 2011, Aldean's recording of "Dirt Road Anthem", recorded previously by both of its writers, country rap artist Colt Ford and Brantley Gilbert (who also wrote "My Kinda Party"), debuted on the Hot Country Songs chart at #57 as an album cut from unsolicited airplay for the week of February 5, 2011.^[9] In March 2011, "Dirt Road Anthem" was selected as the third single from My Kinda Party. Aldean also collaborated with Ludacris on the song "Dirt Road Anthem" at the 2011 CMT Music Awards in Nashville, Tennessee on Wednesday, June 8, 2011. In addition to making number one on the Hot Country Songs chart for the week of July 30, 2011, "Dirt Road Anthem" has also become Aldean's first top ten hit on the Hot 100 chart.

Aldean performed his song My Kinda Party at the start of the 2011 Home Run Derby, aired on ESPN.

Aldean won the CMA Country Album of the Year 2011 as well as the Musical Event of the Year with his duet, "Don't You Wanna Stay", with Kelly Clarkson. It was his first win.

On October 25, 2011 it was announced that Aldean will be performing on “The GRAMMY Nominations Concert Live!! — Countdown To Music’s Biggest Night”, the one-hour special which takes place live on Wednesday, Nov. 30, at the Nokia Theatre L.A. The show will announce nominations in several categories as well as feature performances by past GRAMMY winners and/or nominees.^[10]

Jason Aldean released his fifth single from his award winning album, titled "Fly Over States" on February 6, 2012.

Tours[link]

• Me & My Gang Tour 2006 with Rascal Flatts & Gary Allan (Eric Church was kicked off for playing too long and Jason took his spot)
• Live Your Voice Tour with Tim McGraw 2008
• CMT ON TOUR:Relentless with Lady Antebellum
• Last Rodeo Tour with Brooks & Dunn 2010
• Wide Open Tour 2010 with Luke Bryan (Fall Leg)
• My Kinda Party Tour 2011 with
  • Spring Leg: Eric Church & The JaneDear Girls
  • Fall Leg: Chris Young & Thompson Square
• My Kinda Party Tour 2012 with Luke Bryan & Lauren Alaina
• First night headline at Stagecoach Country Music Festival 4/27/12.

Awards and nominations[link]

Discography[link]

Albums[link]

• 2005: Jason Aldean
• 2007: Relentless
• 2009: Wide Open
• 2010: My Kinda Party

References[link]

External links[link]

• Official website
• Jason Aldean at Allmusic