On 2 September 1967, the first expressway of South Korea, nowadays
Gyeongin Expressway, was assigned as Second-class National Highway 95 Seoul–Incheon () by the presidential decree. The very first section of expressway was opened on 21 December 1968. At first, expressways were assigned as a part of
national highways, but since 31 August 1971, they were assigned as the new separated class:
National Expressways. Under the new numbering scheme implemented on 25 August 2001, expressway numbers were assigned based on a grid system, reflecting the layout proposed in the 3rd Comprehensive National Territorial Planning () in 1992. This updated system was influenced by the numbering conventions of the
Interstate Highway System in the
United States. The details are: •
Trunk routes: These are numbered with two digits. North–south routes are assigned odd numbers, while east–west routes are given even numbers. Primary routes are numbered progressively from south to north or west to east, with the first digit increasing and the last digit ending in either
5 or
0. •
Branch routes: Branch routes off trunk routes have three-digit numbers, with the first two digits corresponding to the main trunk route number. •
Circular routes: Circular routes are numbered in increments of 100, based on the postal code system used from 1988 to 2015. • Seoul: 1,
Capital Region First Ring Expressway (Expressway 100) • Daejeon/Chungcheong: 3,
Daejeon Southern Ring Expressway (Expressway 300) • Incheon/Gyeonggi: 4,
Capital Region Second Ring Expressway (Expressway 400) • Gwangju/Jeolla: 5,
Gwangju Ring Expressway (Expressway 500) • Busan/South Gyeongsang:
Busan Ring Expressway (Expressway 600) • Daegu/North Gyeongsang:
Daegu Ring Expressway (Expressway 700) • Route numbers ranging from 70 to 99 are reserved for potential use following
Korean reunification and are currently unused. • There are a few exceptions: • The
Gyeongbu Expressway is an exception to the numbering rules. Due to its critical importance in the network, it retains the route number 1. • There are multiple east–west branches on
Capital Region First Ring Expressway (Expressway 100), but they are not numbered as the rule of branch routes; instead, they are numbered
110,
120, and
130, respectively. The current highway shield for expressways is inspired by U.S. highway signage, combining the shape of
U.S. Highway shields with the red, white, and blue color scheme of U.S. Interstate shields which are the same colors used in
the South Korean flag. Most of the expressway network is managed by the
Korea Expressway Corporation. Since 2000, however, some routes have been constructed and operated by private companies under government approval. These privately operated routes are managed for a limited time before transitioning to public control. == List of expressways ==