According to the world standards website only 35% of the worlds population drives on the left. However cars, horse drawn vehicles and pedestrians have travelled on the left hand side of the road for centuries in the UK. The reason behind this may reach as far back as Roman times. In 1988 in Swindon, England archaeologists found a preserved track leading to a Roman quarry. The grooves in the road on the left were much deeper than those on the right, suggesting that Roman vehicles travelled on the left because carts would exit the quarry with a heavy load and enter it much lighter. So why was this system in place?
Historians have found evidence of traveling on the left in Ancient Greece, Egypt and Rome. Troops were trained to march on the left side of the road and solders kept left to be free to draw their swords with their right hand. Customs and laws were established in Ancient Rome concerning transport and travel, to ease traffic congestion in the city. Vehicles were banned at certain times of the day and pilgrims were instructed by Pope Boniface VIII to keep to the left side of the road when visiting/traveling in Rome. Today:1
