Keep-left and keep-right rules: origins
Why some countries drive on the left and some others on the right? I have always lived in countries with the keep-right rule, and if you look at the map below you'll see how in the majority of the world the keep-right rules applies (from wikipedia )! Red: Drives on right Blue: Drives on left Accustomed to the keep-right rule, I have always found strange that some countries like UK, Ireland or Australia had the opposite convention. Well, as I learnt today, for some reasons it made and still makes more sense the keep-left rule. Let's see why. Everything started in the Middle Ages or probably even earlier in the Roman empire. In those times (and partially still today...) roads were very safe, so meeting people coming the other way was something best done defensively. Indeed, by keeping the left side of the road, you could more easily protect yourself, by drawing your weapon (attached to the left side), with your right hand. This is even more evident if you were r...