Transport in South Korea roads and various classifications below the national level. Almost all freeways are toll highways and most of the expressways are built, maintained and operated by Korea Expressway Corporation (KEC). The freeway network serves most parts of South Korea. Tolls are collected using an electronic toll collection system. KEC also operates service amenities (dining and service facilities) en route. There are also several privately financed toll roads. Nonsan-Cheonan Expressway, Daegu-Busan Expressway, Incheon International Airport Expressway, Seoul-Chuncheon Expressway and parts of the Seoul Ring Expressway are wholly privately funded and operated BOT concessions. Donghae Expressway was built in cooperation between KEC and
South Korea alliance between the United States and Japan. Korea and Japan have had difficult relations since ancient times, but also significant cultural exchange, with Korea acting as the gateway between Asia and Japan. Contemporary perceptions of Japan are still largely defined by Japan's 35 year colonization of Korea in the 20th century, which is generally regarded in South Korea as having been very negative. Japan is today South Korea's third largest trading partner, with 12% ($46 billion) of exports in 2016. There were no formal diplomatic ties between South Korea and Japan directly after independence the end of World War II