This class is sometimes called "National Roads or Highways". About 5% of the road network are primary roads. Primary roads are the most trafficked and most link neighbouring countries. One such road is the Zimbabwean portion of the Trans-African Highway as it passes through western Zimbabwe. This part of the road network plays a major role in the importation and exportation of the country's ware and transit freight. Among the primary roads some roads are classified as Regional Road Corridors, while some are just primary roads.