About a third of the world’s people live in countries that drive on the left, including India, the UK, Japan, Australia and much of southern Africa. The rest drive on the right. Why the split?
In this article
The sword-hand theory
A popular explanation: most people are right-handed, so a rider on horseback kept to the left of the road, leaving the right hand free to greet — or fight — oncoming travellers. Mounting a horse from the left also put the rider at the roadside. It is plausible, though hard to prove.
Wagons pushed the US to the right
In 18th-century America, large freight wagons were driven by a driver sitting on the rear left horse, so he could control the team with his right hand. Keeping to the right let him watch passing wagons clear. Laws in the US followed.
Napoleon and the right
France adopted keep-right rules around the Revolution, and Napoleon’s conquests spread right-hand traffic across much of continental Europe.
The British Empire and the left
Britain kept to the left and passed it on to its colonies — India among them. After independence, India kept left-hand traffic, as did Pakistan, Bangladesh, Sri Lanka and Nepal. Changing would mean rebuilding road signs, junctions and vehicles nationwide.
Countries that switched
Sweden switched from left to right overnight on 3 September 1967 (“Dagen H”); Samoa switched from right to left in 2009 to make it easier to import cars from Australia, New Zealand and Japan.
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