road

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Elements of a modern asphalt road. (credit: © Merriam-Webster Inc.)

Traveled way on which people, animals, or wheeled vehicles move. The earliest roads developed from paths and trails and appeared with the invention of wheeled vehicles about 3000 . Road systems were developed to facilitate trade in early civilizations; the first major road extended 1,500 mi (2,400 km) from the Persian Gulf to the Mediterranean Sea and was used as early as 3500 . The Romans used roads to maintain control of their empire, with over 53,000 mi (85,000 km) of roadways extending across its lands; Roman construction techniques and design remained the most advanced until the late 1700s. In the early 19th century the invention of macadam road construction provided a quick and durable method for building roads, and asphalt and concrete also began to be used. Motorized traffic in the 20th century led to the limited-access highway, the first of which was a parkway in New York City (1925). Superhighways also appeared in Italy and Germany in the 1930s. In the 1950s the U.S. interstate highway system was inaugurated to link the country's major cities.

For more information on road, visit Britannica.com.

noun

A course affording passage from one place to another: avenue, boulevard, drive, expressway, freeway, highway, path, roadway, route, street, superhighway, thoroughfare, thruway, turnpike, way. See move/halt, open/close.

Idioms beginning with road:
road hog
road show
road to hell is paved with good intentions, the

See also all roads lead to Rome; down the line (road); end of the line (road); get the show on the road; hit the road; one for the road; on the road.

Except for a brief spurt of road building around 1800, the continental United States was extended from the Atlantic coast to the Pacific without the benefit of good roads. The United States had few roads prior to the twentieth century, and most were of poor quality. In towns, most roads were unpaved until the late nineteenth century, and in rural areas most roads were little more than dirt paths into the twentieth century. Federal programs during the 1910s and again during the 1950s eventually provided the United States with adequate roads for motor vehicles.

Roads in Towns Before 1900

On maps, towns in colonial America and the newly independent nation appeared to have excellent roads. Colonial towns, such as Annapolis, Philadelphia, Savannah, and Williamsburg, were built according to founders' designs. Principal functions of the town, including court, church, market, and school, were placed at key locations, and main streets were laid out to connect the buildings.

Squares and circles were placed at the points where the principal streets intersected. Other colonial towns, such as Boston and New York, had random mazes of streets said to be laid out by wandering cows.

Nineteenth-century cities were typically designed around a grid road pattern. Most dramatically, the Commissioners of Manhattan in 1811 laid out the entire island north of the colonial southern tip in a grid of wide avenues running north-south and narrow streets running east-west. As the city grew rapidly during the nineteenth century, the avenues were extended north and crossed by higher-numbered east-west streets. The rectangular blocks formed by the streets were more easily bought and sold by speculators and developers than the irregularly shaped parcels of most colonial settlements.

The main roads of colonial towns were laid with cobblestones obtained from ship ballast. Gravel and blocks made of wood or granite were also used for some road paving in nineteenth-century towns. Although travel on these uneven surfaces was jolting, stones and blocks were an improvement on the vast majority of roads made of dirt. In 1890 the percentage of unsurfaced roads exceeded 30 percent in Washington, D.C., 40 percent in Pittsburgh, and 80 percent in New Orleans and Kansas City. In smaller towns nearly all streets were dirt or gravel. Even Manhattan had many dirt roads in the late nineteenth century.

As cities grew rapidly during the nineteenth century, the poor condition of the roads became an important sanitary issue, not just an inconvenience. Excrement dropped by animals and waste thrown out windows by humans was ground into the dirt or the gaps between stones, spreading diseases such as cholera, typhoid, and dysentery through direct contact and contaminated water supplies.

Cities made major strides in paving roads during the last two decades of the nineteenth century. Brick was widely used beginning in the mid-1880s, especially in midwestern cities. Philadelphia had the highest number of bricks in 1898—2 million square yards—although Des Moines, Columbus, and Cleveland claimed more bricks per capita. Asphalt, already widely used in London and Paris, became a popular paving surface after the discovery of natural beds of pitch in Trinidad, and U.S. cities had 30 million square yards of asphalt paving in 1898. By 1900, after two decades of intensive improvements, Washington, D.C. boasted that it was the best-paved city in the world, and other U.S. cities, especially those along the East Coast, made similar claims.

Rural Roads Before 1900

The first rural routes were one-foot-wide paths traced by deer, buffalo, and other animals, or tamped down by Native Americans on foot. Pioneers of European heritage introduced horses and wheeled vehicles to the trails. Colonial governments, beginning with the Massachusetts General Court in 1639, laid out roads between towns, but few were actually constructed, and most long-distance travel in colonial times was by boat.

The most ambitious road project in the colonial era was the 1,300-mile King's Highway between Boston and Charleston, South Carolina, linking all thirteen colonies. The stretch between Boston and New York opened in 1673, and was widely known as the Boston Post Road because the route was used for postal delivery. Four years earlier, a post road had been opened from New York to Albany, and several others were constructed during the late seventeenth century to carry mail between the colonies. The entire King's Highway was completed in 1750.

Regular service to carry passengers and goods by horse-drawn covered wagon was inaugurated along the King's Highway and other Post Roads in the years immediately before independence. The fastest service, called the "flying machine," took only a day and a half between Philadelphia and New York during the 1770s, but most intercity travel was difficult: the first regularly scheduled stagecoach route between New York and Boston in 1772 took one week, and it took George Washington twelve days to ride from Philadelphia to Boston to take command of the American army.

Fur traders and other European-descendent travelers to the West also followed paths created by animals and Native Americans. European Americans carved out new trails in the interior during the 1770s, including the Watauga Road from Virginia's Shenandoah Valley to east Tennessee in 1773, and the Wilderness Road into Kentucky in 1775. Hundreds of agents organized packhorse transportation along these trails, carrying tools, salt, and cloth west to settlers and returning east with farm products. Philadelphia became the center of packhorse transportation, utilizing such routes as the Forbes Trail across Pennsylvania.

Road building into the interior was extensive in the years immediately after independence, as the new country sought to tie together disparate colonies and a vast frontier. Lacking money to build and maintain roads, states turned to private companies beginning in 1790, when Pennsylvania offered a charter to the Philadelphia and Lancaster Turnpike Company. The company started building a road in 1792 and in 1794 opened the first sixty-two miles. The road was called a turnpike because a gatekeeper turned a pole armed with pikes to permit travelers to pass through after paying the toll.

When the Philadelphia and Lancaster Turnpike proved profitable, it was later extended further west, and hundreds of charters were awarded to turnpike companies by Pennsylvania and other states. Turnpike authorities were typically authorized to erect tollgates every five to ten miles and to charge ten to twenty-five cents. Tolls were used to pay for construction and maintenance.

The turnpike era culminated with the construction of the National Pike, authorized by Congress in 1806. The first 130-mile stretch between Cumberland, Maryland and Wheeling, West Virginia, known as the Cumberland Road, followed a narrow dirt trail known as Nemacolin's Path, created around 1750 by the Delaware Indian chief Nemacolin and Colonel Thomas Cresap. Contracts were given out in 1811, but the War of 1812 delayed the start of construction until 1815, and it was completed in 1818. The National Pike was later extended across Ohio and Indiana and terminated in Vandalia, Illinois. A planned extension to Jefferson City, Missouri, was not built.

The Cumberland Road and other early turnpikes were constructed of crushed stone, but the rest of the National Pike and other later turnpikes were surfaced with macadam, named for Scottish engineer John McAdam, in which a layer of compacted small stones was cemented into a hard surface by stone dust and water. Wetlands and small streams were crossed by placing logs side by side, a style known as corduroy.

Taking advantage of the well-built turnpikes, large heavy vehicles that would have become stuck on dirt roads were placed in service beginning in the 1820s. Concord coaches, pulled by a team of four to six horses, were built in three sizes—six, nine, and twelve passenger coaches—while Conestoga wagons, pulled by six to eight horses, carried freight. A dozen stagecoach lines carried passengers along the National Pike from Washington, D.C. to Wheeling in thirty hours, to Columbus, Ohio in forty-five hours, and to Indianapolis, Indiana in sixty hours.

Rural road construction came to a halt in the United States in the face of competition from canals and especially railroads. Many of the turnpike companies went bankrupt during the 1840s, and the roads deteriorated through neglect during the second half of the nineteenth century. Plank roads, made of wood, were constructed during the 1840s, but these quickly decayed and were not repaired.

Roads in the Automotive Age

The United States had the world's most extensive railroad network in 1900—and some of the world's worst roads. Through the twentieth century, road construction and motor-vehicle ownership reinforced each other. As motor-vehicle sales grew rapidly—exceeding 1,000 for the first time in 1899, 100,000 in 1909, and 1 million in 1916—Americans demanded and got good roads. At the same time, road construction stimulated increased usage of motor vehicles and, ultimately, dependence on them.

When the Office of Public Roads Inquiries undertook the first inventory of all U.S. roads in 1904, the country had 2,151,570 miles of rural public roads, but 1,997,908 miles, or 93 percent, were dirt. Of the 153,662 miles with any kind of surfacing, only 38,622 miles were stone or macadam, while the remainder included 108,232 miles of gravel and 6,810 of shell, sand, clay, brick, or other materials. Only a few hundred miles of roads in the entire country were suitable for motor vehicles.

A majority of Americans still lived in rural areas in the early twentieth century, but operating a motor vehicle there was nearly impossible because of poor-quality—or nonexistent—roads. Consequently, most vehicles were purchased by people living in cities, where streets were paved. Roads in rural areas served primarily as feeders into train stations. A few miles from stations, roads would terminate at streams or county lines or simply disappear into the mud. The cost of hauling grain ten miles from farm to station by road was higher than the cost of hauling it five hundred or one thousand miles by train to big-city markets. It could take an entire day to travel twenty miles in a rural area.

Good Roads Movement

Bicycling was booming as a leisure activity in 1900, and cyclists demanded good roads. The United States had 18 million horses in 1900, and many of their owners also demanded good roads. Bicycle and buggy owners were soon joined by millions of owners of Model Ts, produced on the Ford Motor Company's moving assembly line and sold at a price that was affordable for most American households.

Several organizations pushed for good roads. The League of American Wheelmen founded Good Roads Magazine in 1892 to promote the need for public roads. The National League of Good Roads lobbied for trained engineers to supervise road construction and educated farmers on the benefits of good roads. The National Good Roads Convention in St. Louis in 1903 heard President Theodore Roosevelt declare that a people who could tame a continent should be able to build good roads. In 1919 Colonel Dwight Eisenhower led an army convoy through the West to demonstrate the poor quality of roads and the resulting adverse impact on national security.

For motor vehicle owners, a top priority was construction of a highway linking the East and West Coasts. In the absence of public funding for highway construction, Indianapolis Motor Speedway owner Carl Fisher led a campaign to finance through private contributions the construction of a coast-to-coast highway named the Lincoln Highway, as a memorial to the slain president. For example, to promote the use of cement in highway construction, the Lehigh Cement Company donated 1.5 million barrels (the first cement highway was poured in Michigan in 1908). The Lincoln Highway was completed in 1923.

New Jersey was the first state to finance road construction through taxes, in 1891. Similar legislation was enacted by Massachusetts and Virginia a year later, and in twenty-seven states by 1913. Massachusetts and New York were the only two states collecting license fees from car owners in 1903.

At the federal level, the Office of Road Inquiry (later the Office of Public Road Inquiries, and then the Office of Public Roads) was established in 1893 in the U.S. Department of Agriculture. But the federal government did not fund rural road construction until the 1916 Federal Aid Road Act. The act appropriated $75 million over five years to pay half of the cost of building rural post roads, up to $10,000 per mile (later raised to $20,000 per mile). States had to agree to pay the remaining half, maintain them, and keep them free of tolls. The amount of surfaced roads in the United States increased from 257,291 miles in 1914 to 521,915 miles in 1926. When the system was completed during the 1930s, 90 percent of the population lived within ten miles of a Federal Aid road.

The Federal Highway Act of 1921 called for the designation of a national highway system of interconnected roads. No more than 7 percent of a state's public roads could be included in the system. The complete national system of 96,626 miles was approved in 1926 and identified by the U.S. highway numbers still in use. The Boston Post Road became part of U.S. 1, the Lincoln Highway part of U.S. 30, and the National Pike part of U.S. 40.

Limited-access parkways modeled on the German autobahn highways were built during the 1930s. The New York metropolitan area had a particularly large number of parkways, thanks to longtime parks commissioner Robert Moses, who wanted motorists to have access to the beaches of Long Island and the forests of Westchester County. Envisioning the New York parkways as for recreational driving only, Moses had the clearances under the bridges crossing the parkways designed too low for trucks. The Arroyo Seco Parkway (now the Pasadena Freeway), the first modern freeway in the Los Angeles area, opened in 1940, as did the Pennsylvania Turnpike, the first long-distance limited-access highway through rural areas. Toll roads were built throughout the Northeast between Maine and Illinois in the years immediately after World War II.

Federal interest in limited-access highways dates from the 1938 Federal Aid Highway Act, which proposed a 26,700-mile national system. The 1944 Federal Aid Highway Act expanded the proposed system to 40,000 miles, and the 1952 Federal Aid Highway Act provided the first token appropriation for their construction.

The landmark legislation was the Federal Aid Highway Act of 1956, which established a 44,000-mile toll-free National System of Interstate and Defense Highways and committed the federal government to pay 90 percent of the cost. Most of the miles of interstate highways were constructed to connect cities, but most of the dollars were spent to cross inside cities.

Impact of Interstate Highways

The trucking industry especially benefited from the interstate highways. Rail and truck shared in the growth of freight handling during the first half of the twentieth century about evenly, railroads going from 896 million tons in 1906 to 1.4 billion in 1950, and trucks from nil in 1906 to 800 million in 1950. But over the next two decades, after most rural interstate highways were completed, truck haulage more than doubled to 1.9 billion tons, whereas railroads carried 1.5 billion tons, about the same as in 1950. Railroads were relegated to longer-distance hauling.

With construction of the interstate highways, the United States became a nation of suburbanites. The number of Americans living in suburbs increased from 30 million in 1950 to 120 million in 1990, whereas the number in cities of at least 50,000 inhabitants declined from 60 million to 40 million, and the number in rural areas declined from 60 million to 50 million. In 1950, 40 percent of Americans lived in rural areas, 40 percent in cities, and 20 percent in suburbs. A half-century later, after construction of the interstate highways, 20 percent of Americans lived in rural areas, 20 percent in cities, and 60 percent in suburbs.

People drove farther because they needed to do so to reach jobs, shops, and recreation. Taking advantage of the increased speeds afforded by cars, people chose to make longer trips rather than to reduce travel time. The average motorist drove 25 percent more per year in 2000 than in 1950. Average commuting distance increased 15 percent just between 1950 and 1960, offsetting a 15 percent increase in average speed that decade. Private ownership of cars enabled Americans to move to suburban houses and travel to shops, jobs, and entertainment downtown. Soon the shops, jobs, and entertainment moved to the suburbs, where most of the people lived.

Interstate highways enabled more Americans to drive many more vehicles many more miles on a few more roads, and suburbanization required them to do so. In 1950, 150 million Americans drove 48 million vehicles 458 billion miles on 2 billion miles of paved roads. A half-century later, 250 million Americans drove 201 million vehicles 2.4 trillion miles on 4 billion miles of paved roads. Thus the number of Americans increased by two-thirds, the number of roads doubled, the number of vehicles quadrupled, and the number of miles driven increased six-fold.

Roads in the Twenty-First Century

Faced with the difficulty of increasing capacity through new road construction, engineers tried to ease congestion in the early twenty-first century by making more efficient use of existing highways through designating carpool lanes, building park-and-ride lots, and encouraging employers to stagger work hours. Technological improvements further helped traffic flow. A navigation system in the vehicle, receiving continuously updated traffic data from satellites, alerted the driver to traffic jams and suggested alternate routes. Heavily used freeways were reconstructed with sensors in the pavement that could in the future control speed and distances between vehicles by regulating acceleration, braking, and steering.

Demand was also reduced by charging motorists for the use of existing roads and building new toll roads. Private or special-purpose public agencies gained authorization to construct new freeways during the 1990s, much as railroad companies did a century earlier and turnpike companies two centuries earlier. The California Private Transportation Company built a four-lane highway in Orange County parallel to the congested eight-lane Riverside Freeway (CA 91) between CA 55 on the west and the Riverside County line on the east. The company offered a money-back guarantee that the road would be congestion-free. The promise was kept by changing the toll by time of day, perhaps 25 cents at night and $4 during rush hour. A sign at the entrance to the road announced the cost at that moment to use the road. As the traffic volume increased, the cost was raised until sufficient motorists had chosen the old free road to maintain congestion-free driving on the toll road. Motorists could use the toll road only if they had purchased in advance windshield transponders that recorded the fares then in effect. Tolls were collected through monthly statements based on the records generated by the transponders rather than at tollbooths. Vehicles entering the road without transponders were noted by a sensor, and tickets of at least $100 were issued, either in person by highway patrol officers or through the mail.

Despite the wide variety of available technological strategies, congestion persisted, primarily because most Americans did not behave the way traffic engineers and economists thought they "should." In the 1950s, planners conducted elaborate studies to determine the optimal locations for new roads in response to travel demand patterns. The location of residences, shops, offices, and entertainment centers generated measurable amounts of traffic at specific times of the day. New roads were situated to accommodate existing and projected demand.

Ignored in the planning was the reciprocal relationship between roads and land uses. Roads were located in response to changing land uses, but in reality they also caused changing land uses. A highway built in the middle of nowhere soon sprouted commercial establishments and residential subdivisions near the interchanges. Engineers learned that if they built roads, motorists would come.

Bibliography

Flink, James J. The Automobile Age. Cambridge, Mass.: MIT Press, 1988.

Garrison, William L., et al. Studies of Highway Development and Geographic Change. New York: Greenwood Press, 1969.

Goddard, Stephen B. Getting There: The Epic Struggle Between Road and Rail in the American Century. New York: Basic Books, 1994.

Hart, Virginia. The Story of American Roads. New York: Sloane, 1950.

Hokanson, Drake. The Lincoln Highway: Main Street Across America. Iowa City: University of Iowa Press, 1988.

Holbrook, Stewart Hall. The Old Post Road: The Story of the Boston Post Road. New York: McGraw-Hill, 1962.

Jordan, Philip D. The National Road. Indianapolis, Ind.: Bobbs-Merrill, 1948.

Kaszynski, William. The American Highway: The History and Culture of Roads in the United States. Jefferson, N.C.: McFarland, 2000.

Patton, Phil. Open Road: A Celebration of the American Highway. New York: Simon and Schuster, 1986.

Rae, John B. The Road and the Car in American Life. Cambridge, Mass.: M.I.T. Press, 1971.

Rubenstein, James M. Making and Selling Cars: Innovation and Change in the U.S. Automotive Industry. Baltimore: Johns Hopkins University Press, 2001.

n.

A strip of land along which one may pass from where it is too tiresome to be to where it is futile to go.

    All roads, howsoe'er they diverge, lead to Rome,
    Whence, thank the good Lord, at least one leads back home.
                                                        Borey the Bald

LearnThatWord.com is a free vocabulary and spelling program where you only pay for results!

Dreams about roads often represent one's direction or goal in life. If the road is straight and narrow, what has been planned is being successfully carried out. If the road is winding or bumpy, the dreamer's plans are vague or flexible, or the dreamer is meeting with unexpected change or difficulty. A roadblock may mean the dreamer needs to be more persistent and diligent, or double back and take another route.

Related to animals on roadways.

• r. accidents — results in traumatic injuries because of collisions with vehicles, falling on uneven or slippery surfaces.
• r. founder — traumatic laminitis.
• r. transportation — motor transport.

• Mining - road: tunnel used for hauling excavated material
• U.S. System - road: unit of square measure equal to 1/4 acre
• Roadways and Driving - road: long, open way with paved surface for traveling, esp. by vehicle

For the nautical anchorage, see Roadstead. For public roads, see Highway. For other routes, see thoroughfare. For other uses, see Road (disambiguation).

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

Contents 1 Definitions 1.1 United States 1.2 United Kingdom 2 Historical road construction 3 Design 4 Construction 5 Maintenance 5.1 Slab Stabilization 5.2 Testing 5.3 Joint Sealing 6 Safety considerations 7 Environmental performance 8 Terminology 9 Regulation 9.1 Right- and left-hand traffic 10 Economics 10.1 Construction costs 11 Statistics 12 See also 13 References

Definitions

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

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

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

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

Main article: History of road transport

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

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

A road being torn up.

Surveyor at work with a leveling instrument.

Asphalt layer and roller

Sub-base layer composed of cement-based material being applied during construction of the M8 motorway in Ireland.

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 )}.

Typical pavement strata for a heavily traveled road

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

"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

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

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

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

Pedestrian crossing, line markings and street furniture.

See also: Road traffic safety

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

Main article: Environmental impacts of roads

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

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

Right- and left-hand traffic

Main article: Right- and left-hand traffic

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

Main article: Transport economics

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

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

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

Roads portal AASHO Road Test Byway (road) Design Manual for Roads and Bridges Dirt road Drainage gradient Gravel road

Canada Roads portal Green lane (road) Inca road system Lane List of roads and highways List of OECD countries by road network size

U.S. Roads portal Pavement management system Road slipperiness Shoulder (road) Structural road design Trade route

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39. ^ [2] IGGA
40. ^ How States Preserve Concrete Pavements: CPR pays off in extra pavement life. Better Roads. August 2005.
41. ^ CPR brings dying pavement back to life: Georgia continues to be the leader in concrete pavement restoration, but as the word spreads other states are beginning to use this system to restore deteriorating pavements. April 1997, Roads & Bridges Magazine
42. ^ G. Allen Burton, Jr., Robert Pitt (2001). Stormwater Effects Handbook: A Toolbox for Watershed Managers, Scientists, and Engineers. New York: CRC/Lewis Publishers. ISBN 0-87371-924-7. http://unix.eng.ua.edu/~rpitt/Publications/BooksandReports/Stormwater%20Effects%20Handbook%20by%20%20Burton%20and%20Pitt%20book/MainEDFS_Book.html.  Chapter 2.
43. ^ Charles Seawell and Newland Agbenowosi (1998)."Effects of Road Deicing Salts on Groundwater Systems." Virginia Polytechnic Institute, Department of Civil Engineering.
44. ^ University of Minnesota (2009). "U of M research finds most road salt is making it into the state's lakes and rivers." 2009-02-10.
45. ^ C.Michael Hogan, Analysis of highway noise, Journal of Water, Air, & Soil Pollution, Volume 2, Number 3, Biomedical and Life Sciences and Earth and Environmental Science Issue, Pages 387-392, September, 1973, Springer Verlag, Netherlands ISSN 0049-6979
46. ^ "Traffic-related Air Pollution near Busy Roads". American Journal of Respiratory and Critical Care Medicine Vol 170. pp. 520-526. 2004. http://ajrccm.atsjournals.org/cgi/content/full/170/5/520. 
47. ^ "Road Dust - Something To Sneeze About." Science Daily, 1999-11-30.
48. ^ Laws of New York, Vehicle and Traffic Law § 152
49. ^ "Why In Britain Do We Drive On The Left?". 2Pass.co.uk. © 1996-2007. http://www.2pass.co.uk/goodluck.htm. Retrieved 2007-03-24. 
50. ^ Kincaid, Peter (1986). The Rule of the Road: An International Guide to History and Practice. Greenwood Press. ISBN 0-313-25249-1. http://www.amazon.com/Rule-Road-International-History-Practice/dp/0313252491. 
51. ^ Lucas, Brian (2005). "Which side of the road do they drive on?". http://www.brianlucas.ca/roadside/. Retrieved 2006-08-03. 
52. ^ "Why do some countries drive on the right and others on the left?". http://users.pandora.be/worldstandards/driving%20on%20the%20left.htm. 
53. ^ "International Market Research Reports". Australia CCG 2004 Update: Economic Trends and Outlook (E. INFRASTRUCTURE ). Industry Canada. 2006-02-28. Archived from the original on 2007-11-14. http://web.archive.org/web/20071114181049/http://strategis.ic.gc.ca/epic/site/imr-ri.nsf/en/gr126748e.html. Retrieved 2007-04-17. 
54. ^ "State and Federal Gasoline Taxes". Maps, Reports and history of gas tax in the United States. American Road & Transportation Builders Association ("ARTBA"). Archived from the original on 2007-04-08. http://web.archive.org/web/20070408082904/http://www.artba.org/economics_research/current_issues/state_fed_gas_taxes.htm. Retrieved 2007-05-02. 
55. ^ "International Bridge, Tunnel and Turnpike Association". April 16, 2007. http://ibtta.org/. Retrieved 2007-04-17. 
56. ^ Cardno, Catherine (2008). "Infrastructure: New Report Examines the Potential of Public-Private Partnerships for Transportation Infrastructure". Civil Engineering 78 (11). ISSN 0885-7024. 
57. ^ "Road Transport (Europe)". Overview. European Communities, Transportation. 2007-02-15. http://ec.europa.eu/transport/road/index_en.htm. Retrieved 2007-03-24. 
58. ^ "Thruway Fact Book". New York State Thruway Authority. http://www.thruway.ny.gov/about/factbook/. Retrieved 2011-05-05. 
59. ^ Research and Innovative Technology Administration Bureau of Transportation Statistics U.S. mileage table
60. ^ China to build more highways in 2007
61. ^ Expressways Being Built at Frenetic Pace

This entry is from Wikipedia, the leading user-contributed encyclopedia. It may not have been reviewed by professional editors (see full disclaimer)

Dansk (Danish)
n. - vej, gade

idioms:

• by road    ad landevejen
• hit the road    se at komme af sted
• on the road    på vej, undervejs, på turné, omrejsende
• one for the road    en lille en, inden man kører, afskedsdrink
• road block    vejspærring
• road hog    motorbølle
• road map    vejkort
• road pricing    vejafgift
• road rage    aggressiv adfærd i trafikken
• road sense    færdselskultur
• road show    omrejsende show, turnéforestilling
• road sign    færdselstavle, vejskilt
• road tax    vejskat
• road test    prøvekørsel
• take the road    tage af sted

Nederlands (Dutch)
weg

Français (French)
n. - route, rue, chaussée, voie, (fig) voie, (Naut) rade

idioms:

• any road    (GB, dial) n'importe comment
• by road    par la route
• hit the road    prendre la route
• on the road    en route
• one for the road    un dernier verre pour la route
• out of the road    (ne pas être) en état de marche, (ne pas pouvoir) conduire, (s'être fait) retiré son permis de conduire
• road block    barrage routier
• road hog    chauffard
• road map    carte routière
• road pricing    évaluation des conditions routières
• road rage    violence au volant
• road sense    conscience des dangers de la route
• road show    spectacle de tournée, (TV, Radio) émission itinérante en direct, tour promotionnel
• road sign    panneau de signalisation
• road tax    taxe routière
• road test    essai sur route
• take the road    prendre la route
• take to the road    devenir clochard

Deutsch (German)
n. - Weg, Strecke, (Naut.) Reede, Straße

idioms:

• any road    (coll) jedenfalls
• by road    per Auto
• hit the road    sich auf den Weg machen
• on the road    unterwegs
• one for the road    ein Glas zum Abschied
• out of the road    geh weg!
• road block    Straßensperre
• road hog    Verkehrsrowdy
• road map    Straßenkarte
• road pricing    Gebührerhebung für die Benutzung gewisser Straßen zur Stoßzeit
• road rage    irrationale Aggression im Straßenverkehr
• road sense    Gespür für Verkehrssituationen
• road show    Tournee
• road sign    Verkehrszeichen
• road tax    Wegsteuer
• road test    Fahrtest
• take the road    sich auf den Weg machen
• take to the road    sich auf den Weg machen, losfahren, Vagabund werden

Ελληνική (Greek)
n. - δρόμος, οδός

idioms:

• back road    απόκεντρος δρόμος
• by road    οδικώς
• high road    κεντρική οδός, αρτηρία, δημοσιά
• hit the road    ξεκινώ ταξίδι (με τροχοφόρο)
• on the road    καθ' οδόν, (καθομ.) σε περιοδεία
• one for the road    ένα τελευταίο ποτηράκι
• road block    οδόφραγμα, οδικός έλεγχος (κν. μπλόκο)
• road hog    κακός οδηγός (που οδηγεί εγωιστικά), οδηγός του σαββατοκύριακου, πάπια
• road map    οδικός χάρτης
• road pricing    χρέωση για τη χρήση ορισμένων δρόμων
• road rage    επιθετική συμπεριφορά οδηγού
• road sense    συνετή οδήγηση, αίσθημα κυκλοφορίας
• road show    περιοδεύων θίασος
• road sign    πινακίδα (οδικής) σήμανσης
• road tax    τέλη κυκλοφορίας
• road test    δοκιμή/πρόβα (αυτοκινήτου) σε αυτοκινητόδρομο
• take the road    παίρνω δρόμο, αναχωρώ για

Italiano (Italian)
strada, asfalto

idioms:

• back road    strada secondaria
• by road    in automobile
• hit the road    mettersi in viaggio, togliersi dai piedi
• on the road    per strada, in viaggio
• one for the road    ultimo bicchiere
• road block    blocco stradale
• road hog    pirata della strada
• road map    carta stradale
• road pricing    tassa automobilistica
• road rage    impazienza al volante
• road sense    sesto senso dell'autista
• road show    tournée
• road sign    cartello stradale
• road tax    pedaggio autostradale
• road test    collaudo stradale
• take the road    mettersi in viaggio

Português (Portuguese)
n. - estrada (f), caminho (m)

idioms:

• by road    pela estrada
• hit the road    ir embora
• on the road    a caminho
• one for the road    a última bebida
• road block    barricada
• road hog    "dono da estrada" (gír.)
• road map    mapa rodoviário
• road pricing    relativo ao custo de ruas/estradas
• road rage    violência das estradas
• road sense    dirigir prudentemente
• road show    show itinerante
• road sign    sinal de estrada
• road tax    pedágio
• road test    teste drive
• take the road    ganhar a estrada, partir

Русский (Russian)
дорога, шоссе

idioms:

• by road    автомобилем
• hit the road    отправиться в путь
• on the road    в отъезде, в турне
• one for the road    рюмка на посошок
• road block    дорожное заграждение
• road hog    водитель, едущий посреди дороги
• road map    карта дорог
• road pricing    цена в дорогу
• road rage    гнев водителей ведущий к убийству по дорогам
• road sense    осознание опасностей на дороге
• road show    бродячая труппа
• road sign    дорожный знак
• road tax    налог на пользование дорогами
• road test    автомобильный тест
• take the road    отправиться в путь

Español (Spanish)
n. - carretera, calle, calzada, camino

idioms:

• any road    cualquier camino
• by road    por carretera, por tierra
• hit the road    largarse, irse, emprender viaje
• on the road    estar de gira, estar de viaje
• one for the road    una (copa) de despedida, un (trago) para el camino
• out of the road    fuera del camino
• road block    barricada
• road hog    conductor imprudente
• road map    mapa de carreteras
• road pricing    fijación de cargos por el uso de carreteras
• road rage    cólera del conductor
• road sense    instinto de conductor
• road show    espectáculo teatral presentado por una compañía ambulante
• road sign    señal de tráfico
• road tax    impuesto de circulación
• road test    prueba de carretera
• take the road    emprender camino, ir de pueblo en pueblo
• take to the road    salir al camino (a robar)

Svenska (Swedish)
n. - väg

中文（简体）(Chinese (Simplified))
路, 公路, 道路

idioms:

• by road    由公路
• hit the road    离开
• on the road    在旅途中
• one for the road    以示送行, 斟上最后一杯离别酒给某人送行
• road block    路障, 障碍物
• road hog    自私的司机, 鲁莽的驾驶员
• road map    公路图, 指示, 准则, 说明
• road pricing    某些路段根据电子记录向驾驶员收取的路段费
• road rage    主要使用于英国驾驶人因不耐前车或不满抢道而引起的愤怒
• road sense    路上安全操纵能力, 驾驶技术
• road show    巡回演出, 流动表演
• road sign    交通标志
• road tax    机动车辆每年的道路税
• road test    路上驾驶试验, 实地测验
• take the road    出发

中文（繁體）(Chinese (Traditional))
n. - 路, 公路, 道路

idioms:

• by road    由公路
• hit the road    離開
• on the road    在旅途中
• one for the road    以示送行, 斟上最後一杯離別酒給某人送行
• road block    路障, 障礙物
• road hog    自私的司機, 魯莽的駕駛員
• road map    公路圖, 指示, 準則, 說明
• road pricing    某些路段根據電子記錄向駕駛員收取的路段費
• road rage    主要使用於英國駕駛人因不耐前車或不滿搶道而引起的憤怒
• road sense    路上安全操縱能力, 駕駛技術
• road show    巡迴演出, 流動表演
• road sign    交通標誌
• road tax    機動車輛每年的道路稅
• road test    路上駕駛試驗, 實地測驗
• take the road    出發

한국어 (Korean)
n. - 도로, 가도, 진로

idioms:

• by road    육로로, 자동차로
• hit the road    출발하다, 떠나다, 가버리다
• take the road    지방을 순회하다

日本語 (Japanese)
n. - 道路, …通り, …街道, 鉄道, 方法, 停泊地, 街路

idioms:

• by road    道路を通って
• hit the road    旅を始める, 出かける, 放浪生活を始める
• on the road    旅に出て, 巡業中で
• one for the road    最後の一杯
• road block    道路の障害物
• road hog    はた迷惑な運転者
• road map    道路図, ロードマップ
• road metal    舗道用割り石
• road pricing    有料道路の価格決定
• road rage    暴力運転
• road sense    道路利用の能力
• road show    地方巡回興業, ロードショー
• road sign    道路標識
• road tax    自動車税
• road test    路上テスト, 路上実技試験
• take the road    旅に出る, 出発する
• through road    通過道路

العربيه (Arabic)
‏(الاسم) طريق, شارع, سكه‏

עברית (Hebrew)
n. - ‮דרך, כביש, מסילת ברזל, מעגן, מעבר תת-קרקעי במכרה, חלקת מים מוגנת ליד החוף לעגינת ספינות‬

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