Which side of the road is the “right” side?

September 3, 1967: Road traffic in Sweden switched from driving on the left side of the road to the right.

Considering a trip to the UK to immerse yourself in the country’s long and prosperous automotive history? Lucas Industries aside, there’s a lot to like (hey, it doesn’t take six degrees of separation to find someone who’s been bitten by the Prince of Darkness). With all that the UK has to offer, you may wonder why the Brits insist on driving on the wrong side of the road—or the correct side, depending on your point of view.

Driving on the left—like they do in Great Britain, Ireland, and Scotland, and most British colonies—made sense hundreds of years ago. According to worldstandards.eu, swordsmen rode their horses on the left side in order to fend off adversaries with their right (usually-dominant) hand. That logic prevailed throughout Europe and into the New World.

The left-side tradition began to change in the U.S. in the late 1700s when farmers hauling heavy equipment behind a team of horses would sit behind the left rear horse so they could lash the entire team with their right hand. To better see oncoming traffic, the driver would move the wagon from the left side of the road to the right, and before long, single riders followed suit.

The first law mandating which side of the road was the “correct” side may have been instituted by Russian Empress Elizabeth (Elizaveta Petrovna), who in 1752 declared that riders should travel on the right. In Europe, the French Revolution also impassioned this “right” way of thinking. Traditionally, French aristocracy stayed to the left—forcing peasants to the right—but after the revolution broke out in 1789, the nobility wisely thought it prudent to blend in, and that meant sticking to the right side with the peasants. Right-hand travel became a law in 1794.

Left-hand traffic in Stockholm in 1966
Left-hand traffic in Stockholm in 1966.

Most of Europe (and the rest of the world) came to the same conclusion when picking a side—some much later than others. For example, in the 1950s and ’60s, Sweden relied mostly on left-hand-drive American vehicles, which made driving on the left side of the road difficult since drivers were closer to the shoulder than they were to oncoming traffic. That made negotiating tight squeezes problematic. In the name of safely, and to be consistent with their Scandinavian neighbors, in 1967 Sweden made the switch from driving on the left to driving on the right.

The Swedish word for “right traffic” is “Högertrafik,” and September 3, 1967—the date of the changeover—is remembered as Dagen H (H Day). More than 350,000 road signs were changed during the night, and an additional 130,000 signs were posted to remind drivers that the law was about to take effect. That morning, all non-essential traffic was banned while crews busily reconfigured intersections. The driving ban lasted just a few hours in some areas, but in larger metro areas it dragged well into the next day.

When drivers were ultimately given the green light, there was still some confusion, but overall it went better than expected. Only 157 minor accidents were reported, resulting in 32 personal injuries and zero deaths.

Today, 65 percent of the world’s population drives on the right side of the road, which is an amazing statistic since that means 35 percent of the world drives on the left—a much higher percentage than most Americans would guess. Notable left-hand-drive nations include Australia, New Zealand, South Africa, India, and Japan. You can check out the complete list here.

So which side is the “right” side? As the saying goes, “When in Rome…” For the record, the rest that sentence is: “drive on the right”— Italy sides with the majority.