Postilion

In France, the norm was for horse-drawn carts to be controlled by a rider mounted on one of the drawing horses rather than being controlled from the cart. This was known as a postilion rider. Postilion riders would normally mount the left hand horse of two horses because of the ease of mounting a horse from the left. In the case of four horses, a postilion rider would ride on the left rear-most horse in order to have control of all four horses. It is generally accepted to be safer if the driver of a vehicle is seated closest to the middle of the road. This is one of the main reasons that France has always driven on the right.