The U.S. is among about 75 percent of the countries in the world that drive on the right side of the road, National Geographic says. The reason why most countries use the right lanes dates back to before the invention of cars — and the same is true for the approximately 50 countries in which drivers travel on the left side of the road. Here’s a look at why different countries drive on different sides of the road.
Why Do Some Countries Drive on the Left Side of the Road?
The reason why some countries drive on the left side of the road is likely due to the fact that most people are right-handed. Some of the earliest modes of transportation, such as ancient Roman chariots, were pulled by horses whose drivers likely drove on the left side and defended themselves from oncoming enemies with weapons held in their dominant right hands, the History Channel says. Elsewhere, there was such little traffic from horse-drawn wagons that the preferred side of the road typically varied by community. Eventually, the British government decided traffic should keep to the left, and the law carried down to many of its colonies. That’s why South Africa, Australia and India, among other former British territories, drive on the left side of the road to this day.
Why Do the U.S. and Other Countries Drive on the Right Side of the Road?
Although the U.S. was colonized by Britain, people traveling on horseback and by wagon used the right side of the road, according to the Department of Transportation (DOT). By sitting to the left and carrying guns on their left sides, drivers could better see oncoming travelers and defend themselves when necessary. When Pennsylvania began plans to build a turnpike in 1792, it adopted a law requiring drivers to use the right lane. Soon after, New York legally required drivers to use the right side of all public highways. Every state followed suit by the Civil War, the DOT says.
Right-side travel was further reinforced in 1908 when Henry Ford introduced his popular Model T with the steering wheel on the left side, National Geographic explains, and other auto manufacturers followed the trend. Over the years other countries also adopted right-side travel, often to help facilitate trips across their borders. Canada, for instance, switched from driving in the left lanes in favor of the right to allow easier travel to and from the U.S., the History Channel explains.
Although most countries adopted their respective sides of the roads decades ago, some have switched traffic patterns more recently. Samoa, which previously favored the right side of the road, moved to the left in 2009 to help drivers more easily travel in Australia and New Zealand, which drive on the left. It’s unlikely many other countries will make similar changes due to the costs of changing infrastructure, The Economist says.