Taking Sides: Why do we drive on the left?

Conor McNicholas

It’s something you probably do every day without thinking, but passing on one agreed side of the road is probably the single greatest safety innovation of all time. 

Imagine a world where people could drive wherever they wanted. It would be chaos. And it’s been equally important for horse-drawn vehicles over the millennia.

One of the earliest recorded systems for a “right” side of the road comes from a Roman quarry in Swindon. Archaeologists discovered that the grooves on one side of the road were deeper than the other, indicating how carts were entering (light) and exiting (heavy) the quarry—the Romans were driving on the left just like us. In fact, the ancient world back to the Greeks generally drove on the left, perhaps to keep a right hand free to greet a friend, or to attack with a strong sword arm.

Today, about 34 per cent of the world’s people drive on the left and 66 per cent on the right. Left-handers like us include much of the old British Empire, such as Australia, South Africa, India and Malaysia, plus outliers like Japan and Thailand. No one knows how driving on the right came about, but there’s a suggestion that Napoleon started it out of sheer bloody-mindedness—by forcing his troops to the right in lands he conquered, he stood against the British way of doing things and forced others to cede way to his armies on the highway.

During the Second World War, Jersey had to switch to driving on the right but switched back after liberation in 1945. The same was true of the Falklands under Argentine occupation and later liberation in 1982. A notable exception in Britain is the entrance to the Savoy hotel in London, the only UK road where vehicles are required to drive on the right. The rule is said to date from when horse-drawn carriage doors were opened by hand.