A road is an identifiable thoroughfare, route, way or path between two places which may or may not be available for use by the public; public roads, especially major roads connecting significant destinations are termed highways. Modern roads are normally smoothed, paved, or otherwise prepared to allow easy travel although historically many roads were simply recognizable routes without any formal construction or maintenance. For purposes of international comparison, the 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 should include "bridges, tunnels, supporting structures, junctions, crossings, interchanges and toll roads but not cycle paths". 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. 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. The term was also commonly used to refer to roadsteads, waterways that lent themselves to use by shipping.

The United States has the largest network of roadways of any country with 6,430,366 kilometres (3,995,644 mi) (2005). The People's Republic of China is second with 3,583,715 kilometres (2,226,817 mi) of roadway (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.