Road Totally Explained

Everything about Roadway totally explained

A road is an identifiable route, way 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 recognizable routes without any formal construction or maintenance. 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.
The United States has the largest network of roadways of any single country in the world with 6,430,366 km (2005). India has the second largest road system in the world with 3,383,344 km (2002). People's Republic of China is third with 1,870,661 km of roadway (2004). When looking only at expressways the National Trunk Highway System (NTHS) in People's Republic of China has a total length of 45,000 km at the end of 2006, second only to the United States with 90,000 km in 2005.

Usage and etymology

In original usage, a "road" was simply any pathway fit for riding. The word “street,” whose origin is the Latin strata, was kept for paved pathways that had been prepared to ease travel in some way. Thus, many "Roman Roads" have the word "street" as part of their name. Roads are a prerequisite for road transport of goods on wheeled vehicles Others believe that some roads originated from humans following animal's trails. The Icknield Way is given as an example of this type road origination were man and animal both selected the same natural line. By about 10,000 BC, rough pathways were used by human travelers. The road remained in use after Roman times.

In ancient times, transport by river was far easier and faster than transport by road,

From about 312 BC, the Roman Empire built straight

In the 1600's road construction and maintenance in Britain was traditionally done on a local parish basis.

Road transport economics

Transport economics is a branch of economics that deals with the allocation of resources within the transport sector and has strong linkages with civil engineering. Transport economics differs from some other branches of economics in that the assumption of a spaceless, instantaneous economy doesn't hold. People and goods flow over networks at certain speeds. Demands peak. Advanced ticket purchase is often induced by lower fares. The networks themselves may or may not be competitive. A single trip (the final good from the point-of-view of the consumer) may require bundling the services provided by several firms, agencies and modes.
   Although transport systems follow the same supply and demand theory as other industries, the complications of network effects and choices between non-similar goods (for example car and bus travel) make estimating the demand for transportation facilities difficult. The development of models to estimate the likely choices between the non-similar goods involved in transport decisions "discrete choice" models led to the development of the important branch of econometrics, and a Nobel Prize for Daniel McFadden.
   In transport, demand can be measured in numbers of journeys made or in total distance traveled across all journeys (for example passenger-kilometres for public transport or vehicle-kilometres of travel (VKT) for private transport). Supply is considered to be a measure of capacity. The price of the good (travel) is measured using the generalised cost of travel, which includes both money and time expenditure. The effect of increases in supply (capacity) are of particular interest in transport economics (see induced demand), as the potential environmental consequences are significant.
   Road building and maintenance is an area of economic activity that remains dominated by the public sector (though often through private contractors). Roads (except those on private property not accessible to the general public) are typically paid for by taxes (often raised through levies on fuel), though some public roads, especially highways are funded by tolls.

Environmental aspects

Motor vehicle traffic on roads generate noise pollution especially at higher operating speeds. Therefore, considerable noise health effects are expected from road systems used by large numbers of motor vehicles. Noise mitigation strategies exist to reduce sound levels at nearby sensitive receptors. The idea that road design could be influenced by acoustical engineering considerations first arose about 1973.
Motor vehicles operating on roads contribute emissions, particularly for congested city street conditions and other low speed circumstances. Concentrations of air pollutants and adverse respiratory health effects are greater near the road than at some distance away from the road.

Driving on the right or the left

Traffic flows on the right or on the left side of the road depending on the country. 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, and pedestrians crossing a two-way road should watch out for traffic from the left first. In countries where traffic flows on the left, the reverse is true.
About 34% of the world by population drive on the left, and 66% keep right. By roadway distances, about 28% drive on the left, and 72% on the right, even though originally most traffic drove on the left worldwide.

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. ^(pg15) and may be required to meet standards set by law or official guidelines. 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.
After design, approval, planning, legal and environmental considerations have been addressed alignment of the road is set out by a surveyor. The Radii and gradient are designed and staked out to best suit the natural ground levels and minimize the amount of cut and fill. or twinning. 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 isn't always constructed directly alongside the existing carriageway.

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, 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 weight . A typical tractor-trailer weighing 80,000 pounds (36.287 t) with 8,000 pounds (3.6287 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. pothole 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. Roads can be and are designed for a variety of lives (8-, 15-, 30-, and 60-year designs). When pavement lasts longer then 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 1950's have significantly outlived their intended design lives. 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.
Virtually all roads require some form of maintenance before they come to the end of their service life. Pro-active agencies continually monitor road conditions and apply preventive maintenance treatments as needed to prolong the lifespan of their roads. Technically advanced agencies monitior the road network surface condition with sophisticated equipment such as laser/inertial Profilometers. These measurements include road curvature, cross slope, unevenness, 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.

Terminology

Alignment (road) - Cross slope/Banking/Superelevation, horizontal and vertical curvature of a road.

All-weather road - Unpaved road that's constructed of a material that doesn't create mud during rainfall.

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 which is used mainly as footpaths and bridleways

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

Chicane - Sequence of tight serpentine curves (usually an S-shape curve or a bus stop) in a roadway

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 a concrete, in the U.S. it's 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 - Edge where a raised pavement/sidewalk/footpath, road median, or road shoulder meets an unraised street or other roadway.

Curb extension - (or 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.

Fork - (literally "fork in the road") Type of intersection where a road splits

Guard rail - Prevents vehicles from veering off the road into oncoming traffic, crashing against solid objects or falling from a road

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, similar to a Byway

Interstate Highway System - United States System of Interstate and Defense Highways

Median - On divided roads, including expressways, motorways, or autobahns, the central reservation (British English), median (North American English), median strip (North American English and Australian English), neutral ground [LouisianaEnglish] or central nature strip (Australian English) is the area which separates opposing lanes of traffic

Mountain pass - Lower point that allows easier access through a range of mountains

Milestone - One of a series of numbered markers placed along a road at regular intervals, showing the distance to destinations.

Pavement - The road regarded as a geoconstruction.

Pedestrian crossing - Designated point on a road at which some means are employed to assist pedestrians wishing to cross safely

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

Public space - Place where anyone has a right to come without being excluded because of economic or social conditions

Ranch road - U.S. road which serves to connect rural and agricultural areas to market towns

Road number - Often assigned to a stretch of public roadway. The number chosen is often dependent on the type of road, with numbers differentiating between interstates, motorways, arterial thoroughfares, and so forth

Road-traffic safety - Process to reduce the harm (deaths, injuries, and property damage) resulting from crashes of road vehicles traveling on public roads

Roadworks - Part or all of the road has to be occupied for work or maintenance relating to the road

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.

Shoulder - Reserved area by the verge of a road, generally it's kept clear of all traffic

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

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 which aim to slow down or reduce traffic, thereby improving safety for pedestrians and bicyclists as well as improving the environment for residents

Traffic light - also known as a traffic signal, stop light, stop-and-go lights, robot or semaphore, is a signaling device positioned at a road intersection, pedestrian crossing, or other location in order to indicate when it's safe to cross a roadFurther Information

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