<P> In France, traditionally foot traffic had kept right, while carriage traffic kept left . Following the French Revolution, all traffic kept right . Following the Napoleonic Wars, the French imposed RHT on parts of Europe . During the colonial period, RHT was introduced by the French in New France, French West Africa, the Maghreb, French Indochina, the West Indies, French Guiana and the Réunion, among others . </P> <P> Meanwhile, LHT traffic was introduced by the British in Atlantic Canada, Australia, New Zealand, the East Africa Protectorate, British India, Southern Rhodesia and the Cape Colony (now Zimbabwe and South Africa), British Malaya (now Malaysia, Brunei and Singapore), British Guiana, and British Hong Kong . LHT was also introduced by the Portuguese Empire in Portuguese Macau, Colonial Brazil, East Timor, Portuguese Mozambique, and Angola . </P> <P> The first keep - right law for driving in the United States was passed in 1792 and applied to the Philadelphia and Lancaster Turnpike . New York formalized RHT in 1804, New Jersey in 1813 and Massachusetts in 1821 . </P> <P> Influential in Europe was the 1920 Paris Convention, which advised driving on the right - hand side of the road, in order to harmonise traffic across a continent with many borders . This was despite the fact that left - hand traffic was still widespread: in 1915 for example, LHT was introduced everywhere in the Austro - Hungarian Empire . However, three years later the Empire was split up into several countries, and they all changed eventually to RHT, notably including when Nazi Germany introduced RHT with almost immediate effect in Czechoslovakia in 1938 - 39 . </P>

Which side of the road to drive on