A road atlas is a collection of road maps covering a region as small as a city or as large as a continent, typically bound together in a book. Coil binding or Spiral binding is a popular format for road atlases, to permit lay-flat usage and to reduce wear and tear. Atlases may cover a number of discrete regions, such as all of the federated states or provinces of a given nation, or a single continuous region in high detail, split across several pages.

Source: Wikipedia