LHT was introduced by the U.K. in British India (now India, Pakistan, Myanmar, and Bangladesh), British Malaya and British Borneo (now Malaysia, Brunei and Singapore), and British Hong Kong. All are still LHT, as well as neighbour countries Bhutan and Nepal, except Myanmar, which switched to RHT in 1970, although much of its infrastructure is still geared to LHT and its neighbours India, Bangladesh and Thailand use LHT. Most cars are used RHD vehicles imported from Japan. Afghanistan was LHT until the 1950s, in line with Pakistan (former part of British India).
Although Portuguese Timor (present-day East Timor), which shares the island Timor with Indonesia with LHT, switched to RHT as Portugal in 1928, it switched back to LHT in 1976 during the Indonesian occupation of East Timor.
In the 1930s, parts of China like the Shanghai International Settlement, Canton and Japanese-occupied northeast China used LHT. However, in 1946 the Republic of China made RHT mandatory in China (including Taiwan, which used LHT under Japanese colonization 1895–1945), although Portuguese Macau (present-day Macau) remained LHT, as well as British Hong Kong, despite becoming transferred to China in 1999 and 1997 respectively.
Both North Korea and South Korea use RHT since 1946, after liberation from Japanese colonial power.
The Philippines was mostly LHT during its Spanish and American colonial periods, as well as during the Commonwealth era. During the Japanese occupation, the Philippines remained LHT, also because LHT had been required by the Japanese; but during the Battle of Manila, the liberating American forces drove their tanks to the right for easier facilitation of movement. RHT was formalized in 1945 through a decree by then-president Sergio Osmeña. Even though RHT was formalized, RHD vehicles such as public buses were still imported in the Philippines until a law was passed that banned the importation of RHD vehicles except for special cases. These RHD vehicles are required to be converted to LHD
Japan was never part of the British Empire, but its traffic also drives on the left. Although the origin of this habit goes back to the Edo period (1603–1868), it was not until 1872 – the year Japans first railway was introduced, built with technical aid from the British – that this unwritten rule received official acknowledgment. Gradually, a massive network of railways and tram tracks was built, with all railway vehicles driven on the left-hand side. However, it took another half-century, until 1924, until left-hand traffic was legally mandated. Post-World War II Okinawa was ruled by the United States Civil Administration of the Ryukyu Islands until 1972, and was RHT until 6 a.m. the morning of 30 July 1978, when it switched back to LHT. The conversion operation was known as 730 (Nana-San-Maru', which refers to the date of the changeover). Okinawa is one of few places to have changed from RHT to LHT in the late 20th century. While Japan drives on the left and most Japanese vehicles are RHD, imported vehicles (e.g. BMW, Mercedes-Benz, Porsche) are generally bought as LHD as LHD cars are considered to be status symbols.
Vietnam became RHT as part of French Indochina, as did Laos and Cambodia. In Cambodia, RHD cars, many of which were smuggled from Thailand, were banned in 2001, even though they accounted for 80% of vehicles in the country.