Right- and left-hand traffic

Left-hand traffic (LHT) and right-hand traffic (RHT) are the practices, in bidirectional traffic, of keeping to the left side or to the right side of the road, respectively. They are fundamental to traffic flow, and are sometimes referred to as the rule of the road. The terms right- and left-hand drive refers to the position of the driver and the steering wheel in the vehicle and are the reverse of the terms right- and left-hand traffic. The rule also extends to where on the road a vehicle is to be driven, if there is room for more than one vehicle in the one direction, as well as the side on which the vehicle in the rear overtakes the one in the front. For example, a driver in a LHT country would overtake on the right of the vehicle being overtaken.