Did you know? The reason we drive on the left is that we are right side dominant. Something like 90% of the population is right-handed. We traditionally keep left as this allows our stronger right arm to defend us.

This right-sided dominance gives us Port and Starboard. Boats were loaded by men lifting with their strong right arms into the left-hand side of the vessel. This left-hand side became the port side. The vessel was steered to the jetty by a paddle or a steer board on the right-hand side using the stronger right arm giving us the starboard side. You still see people in small boats steering using an oar on the right-hand side.

steering boat right hand side

So the next question is why do most of the world drive on the right-hand side if we are dominant to the right and should naturally drive or keep to the left. The answer to this is two-fold and is shaped by politics and economics.

The political answer is thought to lie with Napoleon. As he conquered Europe he decreed that his armies should pass in peace. This meant they moved over to the left and instead of passing with their sword arms being able to be offered to an enemy. They showed the weaker left arm to the people coming towards them.

The next part of the answer is economic. As factories, cities and the roads grew so the economy improved and we wanted to carry bigger loads from A-B. With an old horse and cart, you could sit up top pretty much in the middle. And if anything was in front or coming toward you with your dominant right eye you could judge very accurately how much room you had and so kept to the left.

 Steering horse and cart

But in the USA they started to carry bigger loads requiring two pairs of horses or oxen to pull them. As there was nowhere to sit on the wagon the driver would have sat on the rear nearside animal. This is so that his right wipe hand had access to those animals to control them. When you are sat at a height and at the front it doesn’t make any difference which side of the road you are on. But if you are low and with a couple of horses in front of you to accurately judge passing you would have moved over to the right.

Stay tuned to find out more about how we shaped the way we drive.