The expressway network of China is an integrated system of national and provincial-level expressways in China. It is the world's largest expressway system by length, having surpassed the overall length of the American Interstate Highway System in 2011. Between the end of 2014 and 2015, the total length of the network grew from to meaning of expressway were built in 2015 alone. A system of national-level expressways, officially known as the National Trunk Highway System and abbreviated NTHS, with 7 radial expressways (from the capital Beijing), 9 north-south expressways and 18 east-west expressways, forms the backbone of the expressway network in the country. This backbone is known as the 7918 network . In addition, the provincial-level divisions of China each have their own expressway systems.