Transport in Eritrea includes highways, airports and seaports, in addition to various forms of public and private vehicular, maritime and aerial transport. As of 1999, there was a total of 317 kilometres of 950 mm (narrow gauge) rail line in Eritrea. The railway links Agordat and Asmara with the port of Massawa; however, it was non operational since 1978 except for about a 5 kilometre stretch that was reopened in Massawa in 1994. Rehabilitation of the remainder and of the rolling stock has occurred in recent years. By 2003, the line had been restored from Massawa all the way through to Asmara. The Eritrean highway system is named according to the road classification. The three levels of classification are: primary (P), secondary (S), and tertiary (T). The lowest level road is tertiary and serves local interests. Typically they are improved earth roads which are occasionally paved. During the wet seasons these roads typically become impassable.