The driving side of a road is the side where vehicles must drive. Each country says whether vehicles will drive on the right-hand or left-hand side of the road. This is sometimes called the rule of the road. This basic rule makes traffic move more easily. It also lowers the risk of head-on collisions. Today about 66.1% of the world's people live in countries who drive on the right-hand. 33.9% live in countries that drive on the left-hand. Do not confuse between left-hand drive (LHD) and to drive on the left-hand side of the road which is the right-hand drive (RHD).