A great hindrance to Burundi’s economic development is lack of adequate transport. The country has limited ferry services on Lake Tanganyika, few road connections to neighboring countries, no rail connections, and only one airport with a paved runway. Public transportation is extremely limited and private bus companies operate buses on the route to Kigali but not to Tanzania or the Democratic Republic of Congo. Roads total 12,322 kilometres (7,657 mi) as of 2004, and only about 7 percent of them are paved and remain open in all weather; the rest are classed as local roads or tracks. In 2003, there were 24,000 passenger cars and 23,500 commercial vehicles. On paper there are 90 public buses in the country but few of these are operational. Transport is extremely limited and private bus companies operate buses on the route to Kigali but not to Tanzania or the Democratic Republic of Congo. Burundi does not possess any railway infrastructure, although there are proposals to connect Burundi to its neighbours via railway. At a meeting in August 2006 with members of the Rwanda Patriotic Front, Wu Guanzheng, of the Communist Party of China, confirmed the intention of the People's Republic of China to fund a study into the feasibility of constructing a railway connecting at Isaka with the existing Tanzanian railway network, and running via Kigali in Rwanda through to Burundi.Tanzanian railways use 1,000 mm (3 ft 3 3⁄8 in) metre gauge, although TAZARA and other neighbouring countries, including the Democratic Republic of the Congo(DRC) use the 3 ft 6 in (1,067 mm) gauge, leading to some potential difficulties.