Highways are major roads used by the public that connect cities, historic or natural sites, or rural locations. There have been trails or rough roads throughout the world for thousands of years. The Roman Empire built highways that in a few cases are still in use. Other empires built similar road systems to aid communications and the movement of troops. In the 20th century, highways were built to facilitate the movement of people, goods, and military forces. The invention and development of gasoline engines that powered trucks, cars, buses and other vehicles led the United States to build highways.

The United States has the most extensive highway system in the world, some of which are county or state roads. Others are part of the numbered highway ...