Civil war crippled the development of transport infrastructure; in 1987, Chad had only  of paved roads. Successive road rehabilitation projects improved the network to  by 2004. Nevertheless, the road network is limited; roads are often unusable for several months of the year. With no railways of its own, Chad depends heavily on Cameroon's rail system for the transport of Chadian exports and imports to and from the seaport of Douala.