Why Sweden Changed Driving Sides Overnight

Jan Collsiöö — Så var det. Public Domain.

September 3, 1967, was a big day for Sweden. Högertrafikomläggningen, or more simply, Dagen-H. It was the day the country switched from driving on the left to the right side of the road.

It was, predictably, absolute chaos, but the act of switching sides isn’t the most surprising part. It’s that the switch happened in 1967 when there were 1,976,248 registered vehicles Sweden. With that many cars on the road, switching sides was a logistical nightmare. It took a month and military aide to change signs and markings overnight, not to mention manage the nearly two million drivers grappling with the change. So if everything was set up for left-hand driving, why change sides at all? Why did Sweden change driving sides in 1967!?

To get to the bottom of this one, we need to talk about ancient Rome, the British Empire, Napoleon, the Second World War, freight transport, and the Ford Model T.

If you’re living in North America, most of Europe, most of South America, and large parts of Asia and Africa, you’re accustomed to sitting on the left side of the car and driving on the right side of the road. For a handful of countries, about 35 percent of the world, the custom is sitting on the right of the car to drive on the left. Whichever side you’re on, it’s possible you’ve never done the other.

I’ve done both, though I’ve only driven on the left for about three hours in the bush in Australia, so it wasn’t intense city driving. But it was HARD! My eyes naturally go up and to the right for the rearview mirror; looking left felt unnatural. I felt very unsure about where my wheels were, so I constantly checked my side mirrors. My brain saw oncoming traffic and freaked out we would crash before I remembered cars were supposed to be on my right. I can’t imagine how hard it would be to suddenly change driving sides, especially in familiar areas you can navigate without a second thought.

So what’s the deal with sides anyways? Like so many facets of modern life, the story starts with ancient civilizations…