Most of the world drives on the right side of the road, but a minority of countries drive on the left. How do countries decide which side they’ll drive on?
The answer varies from country to country, but in most cases, the side a country drives on comes down to history and economics. In feudal Europe, people would travel on the left side of the road because most people were right-handed and wanted the arm that they used for their sword (or other weapon) between them and anyone who approached. As a result, traveling on the left became customary.
As Europeans began colonizing other parts of the world, they imposed their direction of travel on those areas.
Two things changed that. In areas with large farms, like the United States, wagons that were meant to carry large loads didn’t have driver’s seats. To control the horses pulling the load, farmers would ride on the left horse. Traveling on the right side of the road made sense because it allowed the farmer to see the space between the wheels of his wagon and any approaching wagons to avoid collisions.
At about the same time, Napoleon Bonaparte, who was left-handed, was coming to power in France. Since he liked to keep his sword arm between himself and anyone who approached, he preferred to travel on the right side of the road, and decreed that his army would do the same. Though this custom of approach was in place prior to Napoleon taking power, he imposed that direction of travel on the areas he took over throughout Europe. So, Americans and most of mainland Europe started traveling on the right, whereas other areas, like Great Britain, stuck to the left.
As Europeans began colonizing other parts of the world, they imposed their direction of travel on those areas. In much of the world, you can tell the side of the road a country travels on based on its status as a former colony. Former colonies of England tend to drive on the left, while former French and American colonies tend to drive on the right.
There are exceptions, of course. Canada drives on the right because of their proximity to and longstanding trade relationship with the United States. Sweden used to drive on the left, but because they had a burgeoning automotive industry that depended on trade with countries that drove on the right, they switched. Ghana, a former British colony, also switched from driving on the left to driving on the right because that’s how most of their neighboring countries drove. On the other hand, the U.S. Virgin Islands is a territory of the United States, but they drive on the left.