Why do some countries drive left and others right?

Driving left side or right?

If you’ve been studying our website closely you’ll know that our truck, Jigsaw, is right-hand drive and it was designed to drive left. Which means that this entire Earthcircuit is, for us, happening on the wrong side of the road.  “No!” Americans will say, “It is you Brits who drive on the wrong side, just like the Aussies and Japs. Everyone else drives on the right side of the road.” Well, I’m going to explain why, indeed, most of the world drives on the right side even though it is the wrong side – and why a few select countries drive on the left side which is, in fact, the correct side.

For those who can’t be bothered to read this entire article, I’ll sum it up here: Are you right or left handed? I’m guessing right – and that’s why you should be driving on the left – simple, no? But how did we reach the current state of affairs? And does it really matter which side any particular country chooses to organize its traffic?

So let us go back in time, before there were any cars at all but not before there were cities and roads. These ancient metropolises sometimes had worse traffic jams than we have now. Ox carts, horse-drawn carriages, chariots, peasants pushing barrows, slaves carrying their masters and hundreds of street people forcing their way through the mêlée that was the typical scene in any town or city.

The chaos was made worse, of course, since usually there were no enforced traffic regulations of any kind – a situation that persisted right up until the twentieth century even in some European countries. However, more enlightened authorities ruled that traffic must travel on the left side of the road – there is evidence that the Romans practiced this and, too, in the bustling cities of ancient India where the geometries of clockwise motion (up the left side and back down on the right) held religious significance.

Drive on the left side even before there were cars

Before the modern age, you see, there is an important thing to consider: traveling on the left side forces anyone coming towards you to pass on your right side. And for the majority of people this means that they can more easily attack or defend themselves using whatever weapon they are holding in their right hand. Or, if violence is not your thing, moving on the left, means you can more easily shake hands or high-five a person coming towards you with your right hand: Mounting a horse is generally done with the left leg first. To do this safely, standing by the side of the road and not in the middle of the traffic means that the traffic should be moving on the left side of the road (try this with your bike). Sitting on a horse or on a cart behind a horse means that to use a whip (with your right hand) you must be traveling on the left hand side of the road if you don’t want to get caught up with pedestrians as you raise your hand back to strike (try that on your bike, too).

French Empire in early 1800's
Napoleon’s Right Sided Europe

So, originally, we can say that everywhere in the world had a traffic system like the UK does now. Well, what happened then? Basically the French started changing things around. In the eighteenth century, two things happened. First, there was an increase in large wagons being pulled by several horses, designed to carry big loads across this massive country. The driver of such a transport generally sat on the left rear horse so that he could apply his whip (in his right hand) to all the horses in front of him. This meant that he preferred to travel on the right so to check for clearance with oncoming traffic. Secondly, there was the French Revolution. In France, it was the aristocracy who used non-commercial horse-drawn vehicles – and they, in keeping with the natural way, travelled on the left side. It was the peasantry, walking on foot, who passed on the right hand side so that they had a better view of the oncoming travel – much as pedestrians are advised to do all over the world today when there is no safe sidewalk to use. This rightism became a symbol of the revolution, so that everyone was obliged to travel on the right in the same way as a horse-less peasant, including the aristocrats keeping a low profile.  A few years later, along came Napoleon who conquered much of Europe – wherever he went, he pressed the new right-side form of travel into law.  It is thought, too, that, with his massive armies marching up and down all over the continent, traveling on the right would reduce the opportunities for inter-regimental fighting as the columns of soldiers passed each other. Napoleon, too, was left-handed.

So for another hundred years, until the birth of motorized locomotion, the states, and their colonies worldwide, that had been conquered by Napoleon travelled on the right. The others, namely Portugal, Sweden and the British and Austro-Hungarian Empires and their colonies kept to the left.

In the case of the US, while it was still under British control, people generally kept to the left, too, in the busy cities – although in the vast, undeveloped areas, there was little regulation. The introduction of great big wagons pulled by a fleet of horses and controlled from the rear left horse, like France, forced much of the inter-urban traffic to travel on the right. And then, when America won its independence, they made the switch permanent, in a move to severe links with the British, but also partly in response to the many immigrants who were used to right-side travel having come from those Napoleon-conquered states in Europe.

For mainland Europe, Hitler forced Austria, Czechoslovakia and Hungary to switch to the right where they remained after the Second World War; China and Korea switched to the right, once free from Japanese control (where the custom had, of course, long been to travel on the left.

For the rest of the world we can say that most countries travel on the right in an effort to conform to their neighbors while much of the former British Empire continues on the left. In the case of Pakistan and India (which had been traditionally left-siders before the British arrived), they felt that to change would bring too much disruption, not least to camel trains that often plodded on through the night, on the left side of the road, while their drivers slept. Another notable exception was Myanmar where the superstitious president ordered a change from left to right on the advice of a wizard.

So then, there we are, most of the world now travels on the right, and the roots of that stem from political reasons rather than any practical reasons. And, unfortunately, there could be a price to pay for this disregard of the natural, instinctive norms of a right-handed humanity. There hasn’t been much research done on whether it is safer to be a leftist or a rightist – such an experiment would be enormously difficult to design: where would we find a population who were completely used to driving on both sides in order for genuine comparisons to be made? How could we distill the effect of the side of the road from all the other cultural aspects of driving, the design of roads, the proficiency levels, the efforts of traffic police and deterrence effects of the judicial system between one country and another? We can look at the experiences of Sweden which made the change from left to right in 1967; traffic accidents went down dramatically for a while after the switch but returned to more or less the same levels as before once the public had got used to the new system and were less cautious. But there is not much to learn there, except that it is much more important that you drive with careful attention.

Right-siders reminded to use the left as they enter Kent, UK We can identify a few advantages to driving on the left. The dangerous part of the road is, of course, the center where vehicles pass in opposite directions. The energy of impact is more substantial there – the time necessary to avoid an impact is a fraction of what is available to avoid impacts with people or objects on the side of the road. It might make sense to have your good hand on that side, to be sure – humans also have ocular preference where the majority favors their right eye over their left. This feedback between your eye and your hand on the steering wheel is the crucial moment of safe driving. Consider, then, sitting on the right hand side of your car – you keep your good hand within this feedback loop, while your left is free to operate the gear stick, as you turn a corner, say, or fiddle with the radio. The gears, the buttons on the radio, etc. are generally digital switches – on or off, one, two, three, four, and so on. The point is that the hand remaining on the wheel is in an analogue control mode and should demand much more of your brain power to keep it good than a mere switch. Another point to consider is when you are reversing and you look over your shoulder, through the rear window to see where you are going:. If you sit on the left hand side of your car, your bad hand remains on the steering wheel and is forced to become part of the analogue feedback loop…

Of course, the real world is much more complicated: in cultures with relaxed driving habits, it may well be better to use your right hand for operations around the interior of the vehicle, like finding a radio station, drinking coffee or retrieving a dropped mobile phone. Using your good hand for this may reduce the time that there is only one hand on the steering wheel. One particular nation might extensively employ dual carriageways which separate the traffic directions, while strictly enforcing speed limits on more dangerous single carriageway roads. There are many, many more vehicles with manual gear shifts in Europe than North America, too, for instance. But consider this: The UK, which drives on the left, has consistently fewer road accidents and casualties than the rest of right-driving Europe.


Drive on the left
European Road Casualty Per Million Population

“Visitors are informed that in the United Kingdom traffic drives on the left-hand side of the road. In the interests of safety, you are advised to practise this in your country of origin for a week or two before driving in the UK.”
— United Kingdom Ministry of Transport

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