- This page is related to transport, you may be looking for the 2002
Hindi movie Road by Ram Gopal Varma starring Vivek Oberoi and Manoj Bajpai.
A road in Japan.
A road is a strip of land connecting two or more destinations.
In the context of railways, a road is a single track, which may
be part of a multi-track system or may be an isolated line. In the context of sea transport, a road is an anchorage.
Word, history, funding
In original usage, a "road" was simply fit for riding ("road" is cognate with "ride", e.g.: ships ride at anchor in roads).
The word "street" was kept for roads that had been prepared to ease travel in some way (thus, many "Roman Roads" have the word
"street" in their names whose origin is the Latin strata,
given before the usage changed).
However modern usage does not usually make this distinction, and it is only important since place names often hold the earlier
usage in them; these days roads are also prepared in some way. This includes, at the least, the removal of trees and smoothing of
the ground. In some dialects, lower grade roads are called trails and wheel tracks, and it is uncertain where
"road" begins and trail ends. Roads are a prerequisite for road
transport of goods on wheeled vehicles.
Many historical examples exist of road and road-building. Some of the most famous are the Roman roads and the Incan courier roads. In ancient times, transport by
river was far easier and faster than travel by road, especially considering the cost of
road construction and the difference in carrying capacity between carts and river barges - provided only that the rivers were navigable in the right places; availability of water
transport also influenced settlement patterns. A hybrid of road transport and ship transport is the historic horse-drawn
boat.
During the industrial revolution, a development of the
road was made: the railway. Today, roads are almost exclusively built to enable
travel by car and other wheeled vehicles, and in most countries road transport
is the most utilized way to move goods.
Roads situated in cities are often, but not always, called streets or alleys; this
reflects the historical fact that when they were first named there were more likely to be unmade roads in open country and paved
roads in urban areas. This leads to roads being sometimes named from their destination or direction, while streets may be named
from their location.
Road building and maintenance is one of the few areas of economic activity (compare military spending) that remain 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 are funded
by tolls.
Driving on the right or on the left
Traffic drives, depending on the country, either on the right or on the left side of the road, see Rules of the road.
In countries where traffic drives on the right:
- traffic signs are mostly on the right side of the road
- roundabouts (traffic circles) go counter-clockwise
- pedestrians crossing a two-way road should watch out for traffic from the
left first
and conversely.
Traffic flow and road design in both cases are each other's mirror
image.
Design
Road design consists of two important technical aspects:
- geometrical road design
- structural road design
Besides these two technical sides of the design, environmental issues, planning issues and juridical issues are important.
Construction
Roads are built by removing vegetation. The soil is tested to see if it will support weight and if not, a layer of soil is
removed and replaced. The soil is compacted to form what is known as a "base course". On top of the base course is placed a
wearing course which consists of asphalt or concrete. The main purpose of the wearing course is to prevent moisture from entering the road.
On the side of the road there may be retroreflectors on pegs, rocks
or crash barriers, white toward the direction of the traffic on that side of the road, and red toward the other direction. In the
road surface there may be cat's eyes: retroreflectors that
protrude slightly, but which can be driven over without damage.
Road signs are often also made retroreflective. For greater visibility
of road signs at daytime, sometimes fluorescence is applied to get very bright colors.
Causeway
A causeway is an elevated road, not on a bridge but on elevated ground, often through a body of water or through wet land. It
may be constructed as a 'coffer dam': two parallel steel
sheet pile or concrete retaining walls, anchored to each
other with steel cables or rods. This construction may also serve as a dyke that keeps two bodies of water apart, e.g. with a different water level on both sides, and/or with
salt water on one side and fresh
water on the other side (this may also be the primary purpose, the road being a side benefit).
Examples are those that connect Marken, Singapore and Venice to the mainland, and the Afsluitdijk, Brouwersdam, Markerwaarddijk.
Road Terminology
See Also
External links
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