Road

A road is a strip of land connecting two or more destinations. In original usage, a "road" was simply fit for riding ("road" is cognate with "ride", e.g. with ships riding 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, 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 (but, of course, availability of water transport also influenced settlement patterns). 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 objects.

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 made roads in cities.

Road building and maintenance is one of the few areas of economic activity that remain dominated by the public sector (though usually 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.

Traffic drives, depending on the country, either on the right or on the left side of the road. Driving on the left occurs mainly in the UK and its former colonies. In countries where traffic drives on the right overtaking occurs on the left and conversely.

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 stick out a bit, but you can drive over them.