Sometimes I think I know something, only to discover that either I was wrong, or that there is a lot more to the story. So I was thinking about the countries that drive on the left side of the road, like the United Kingdom, and how all of the other countries driving on the left were formerly part of the British Empire.

A map indicating which countries drive on the right side of the road, and which drive on the left side. Author Benjamin D. Esham (bdesham) via Wikimedia Commons

A map indicating which countries drive on the right side of the road, and which drive on the left side. Author Benjamin D. Esham (bdesham) via Wikimedia Commons

But then I remembered that Canada drives on the right. Although that could be explained by their long border and close relationship with the United States, I had to find out for sure. This is the best site I found for detailed information about which countries drive on which side of the road, and the history behind it.

Venturing back into the past, the accepted wisdom is that traffic, mostly people walking and riding horses, originally stayed to the left side of roads because most people are right-handed. At a time when people were often required to protect themselves with swords and other weapons, they needed their right hand to be on the side closest to any potential threat.

Equestrian Portrait of Charles V by Titian (1490-1576) in 1548. Notice the weapon in his right hand. Photo via Wikimedia Commons

Equestrian Portrait of Charles V by Titian (1490-1576) in 1548. Notice the weapon in his right hand. Photo via Wikimedia Commons

But things started to change all around the world. France switched to the right side of the road and one theory is that they didn’t want to be like the English. Another theory is that after the French Revolution, the new leaders wanted to change all the old ways. The same is said of the United States after our own revolution, that we wanted to do everything differently than the British. Of course, cultural changes don’t always happen quickly, and aren’t always the result of one event or idea, so that’s difficult to prove or disprove.

Surprisingly, Napoleon is often blamed for the spread of right lane traffic. It may simply be coincidence that the areas he conquered moved to the right, while the others stayed to the left. I didn’t find anything to indicate why Napoleon may have wanted all traffic to move to the right. Maybe just because he could. It seems like he would have been that kind of guy.

What I found most interesting was how many countries changed their side of the road into the twentieth century. I would have thought everything was pretty well set in place by that point. World War II was responsible for many areas changing the way they drove, by force rather than choice.

I was really surprised to find that in the 1960s Great Britain considered switching to the right, but decided the costs would be too great.  Sweden switched from the left to the right in 1967, even though over 80% of the population wanted to stay on the left. In 2009 (yes, really, 2009) Samoa switched the other way, from right to left, mostly to bring it in line with nearby Australia and New Zealand, which drive on the left.

So what about Canada? The country had actually been split for years, with the French territories driving on the right and the English territories driving on the left. In the 1920s, the left-sided provinces switched to right side to be in line with the rest of the country and with their southern neighbor, the United States. The last to switch was Newfoundland in the late 1940s.

***For added fun, check out this site that shows how countries handle border crossings into countries that drive on other side of the road.