<P> The first reference in English law to an order for LHT was in 1756, with regard to London Bridge . </P> <P> Some historians, such as C. Northcote Parkinson, believed that ancient travellers on horseback or on foot generally kept to the left, since most people were right handed . If two men riding on horseback were to start a fight, each would edge toward the left . In the year 1300, Pope Boniface VIII directed pilgrims to keep left . </P> <P> In the late 1700s, traffic in the United States was RHT based on teamsters' use of large freight wagons pulled by several pairs of horses . The wagons had no driver's seat, so the (typically right - handed) postilion held his whip in his right hand and thus sat on the left rear horse . Seated on the left, the driver preferred that other wagons pass him on the left so that he could be sure to keep clear of the wheels of oncoming wagons . </P> <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>

When did usa start driving on the right