It can be disconcerting to get off the plane in southern Africa and see people driving on the left side of the road. While 35 percent of the world’s population drives on the left, that represents only a handful of countries, mostly old British colonies—and Japan.
As with most protocols, there’s a pragmatic reason behind the practice, this one having to do with the fact that most people are right-handed. Ancient Romans drove chariots with the reins in their dominant right hands to allow them to whip a horse with their left. That reduced the chance of accidentally lashing a passing chariot. Knights wore their scabbards on the left so they could be drawn easily while keeping their right hand closer to their adversary. Sheaths worn here were less likely to get tangled up with other traffic and made mounting the horse from the left advisable. Traveling on the left also made sense when it came to dismounting as the rider would get off the horse away from traffic.
Then in the late 1700’s, times changed and with them, traffic behaviour. French and American teamsters (wagon drivers) began hauling farm products in big wagons pulled by several pairs of horses. The teamster sat on the left rear horse, keeping his right had free for the whip. He preferred oncoming and overtaking traffic to pass on the left so he could keep an eye on their wagon wheels and make sure they didn’t get tangled up with his. It made sense therefore to be on the right side of the road.
Edicts to drive on the right began appearing throughout Europe in the mid 1700’s for practical, social, and political reasons, with sides being determined by the ruling country. For example, the practice in France was to have aristocracy on the left and peasants on the right. Not surprisingly, after the storming of the Bastille, the ‘haves’ wanted to blend in with the ‘have nots’, so moved to the right. Napoleon spread the practice by making it compulsory in countries he conquered. Britain was chief amongst the countries who resisted him and left-handed driving remained mandatory in Britain and countries of the British Empire.
After the American Revolution, American states began introducing right-handed driving, beginning with Pennsylvania in 1792. Those parts of Canada driving on the left switched over by 1924. Newfoundland was the holdout, moving over only in 1947 before it joined Canada in 1949.
American-produced cars helped spread right hand driving globally. As automobiles’ reliability and demand increased beyond their borders, many countries changed their rules of the road out of necessity.
Britain and many of the countries it colonized, including those in southern Africa, remain holdouts to left sided driving to this day. There’s debate as to why the practice continues, with the consensus generally that it would be unreasonably expensive and complex to change the infrastructure.