Driving on the left made sense
Before the late 1700s, most societies traveled on the left-hand side of the road. Most people are, and always have been, right-handed. Therefore it made sense for soldiers to march on the left-hand side of the road so that they didn’t hit their comrades and could easily duel an opponent. It’s also easier to mount a horse from the left-hand side if you are right-handed.
If it makes sense to keep left, why did societies switch?
There are a couple of reasons given as to why societies began driving on the left-hand side:
1. Horses and Wagons
As machinery became bigger, it required larger wagons and teams of horses to transport it. A wagon driver would sit on the left rear horse and leave his right hand free for the whip. If the wagon driver had driven on the left, he would not have seen what he was passing as easily. Therefore wagon drivers began keeping to the right, and slowly so did everyone else.
2. The French
Napoleon Bonaparte was left-handed. There’s a legend that he marched his armies on the right-hand side of the road and declared that everyone else in France should travel on the right too. The change is said to have spread to other European countries.
Is there anywhere in Britain where you don’t drive on the left?
Gibraltar is the only British territory where you won’t find people driving on the left. Because they share a land border with Spain, the Gibraltarians began driving on the right in 1929.
Which other countries drive on the left?
Many former members of the British Empire drive on the left-hand side of the road, as do the Japanese. Some other European countries, such as Sweden and Portugal, used to drive on the left but switched so that it was easier to travel to neighbouring countries. Citizens of other countries, such as Austria and Spain, were once driving on the left in parts of the country and on the right in other parts.