Road

Road, surfaced or unsurfaced path over which vehicles travel. Roads include streets; local and secondary thoroughfares linking rural areas and communities; primary highways, including freeways and expressways, connecting larger communities; and in the United States the Federal Interstate Highway System, a system of freeways connecting most cities larger than 50,000. The first roads appeared around 3000 B.C., soon after the invention of the wheel. Later the Chinese and Egyptians built roads, but the Romans are generally considered the first really knowledgeable road builders. In the United States, roads remained crude, unsurfaced or covered with gravel or wood planks, until the beginning of the 20th century; the invention and growing popularity of the automobile aided road development around this time. Today, the United States has almost 4 million mi (6.5 million km) of roads.