Over the course of the 20th century, there was a gradual worldwide shift from driving on the left to the right. Portugal changed to right-hand traffic in 1928, and the parts of Canada which were still driving on the left changed over by 1923. The remainder of Italy changed over in the 1920s after Benito Mussolini came to power; Austria and Czechoslovakia changed when Germany annexed or occupied them in late 1930s, and Hungary followed suit. In Austria the build-up of new traffic lights and rebuilding of tram tracks was started before the annexation. The Latin American countries of Panama and Argentina changed in 1943 and 1945 respectively, and the Philippines and China followed suit in 1945 and 1946 respectively. Belize changed to right-hand traffic in 1961. Sweden changed in 1967 and Iceland did as well in 1968. Burma changed, allegedly on the advice of a wizard,[15] in 1970. (For the logistics involved, see the Swedish experience at Dagen H.)
Taiwan drove on the left under Japanese rule, but changed to driving on the right in 1946 after the government of the Republic of China assumed administration; the same happened in North and South Korea, another former Japanese colony. However, some trains in Taiwan and Seoul still keep to the left, as does pedestrian traffic in the Seoul subway system.
The most common reason for countries to switch to right-hand traffic is for conformity with neighbours, as it increases the safety of cross-border traffic. For example, several former British colonies in Africa, such as The Gambia, Sierra Leone, Nigeria, and Ghana, have changed from driving on the left to the right, because they all share borders with former French colonies, which drive on the right. The former Portuguese colony of Mozambique continues to drive on the left, which is a legacy of its Portuguese past; even though Portugal itself changed over in the 1920s, Mozambique continues to drive on the left because all its bordering countries do. More info at:
https://en.wikipedia.org/wiki/Right-_and_left-hand_traffic
