The transport in Azerbaijan involves air traffic, waterways and railroads. All transportation services in Azerbaijan except for oil and gas pipelines are regulated by the Ministry of Transportation of Azerbaijan Republic. For Soviet transportation, see Transport in the Soviet Union. Railways There are of rail tracks out of which only are in common carrier service and are industrial lines. Total: (2013) Country comparison to the world: 59 Broad gauge: gauge Railway links with adjacent countries Timeline Metro System Currently, the only metro system in Azerbaijan is the Baku Metro, located in Baku, the country's capital. New plans to open metro systems in the most populated and developed cities of Azerbaijan were unveiled. Sumgayit, Nakhchivan and Ganja all plan to have subway systems in the future. Suburban Railway Roadways There are about 25,000 kilometres of roads in Azerbaijan, serving domestic cargo traffic and giving access to international main highways. Highways are mostly in fair condition and need an upgrade to international standards in a view to accommodate growing transit traffic. Main and rural roads are in poor condition and in urgent need of rehabilitation and maintenance. The total vehicle fleet in Azerbaijan was about 517,000 in 2004, with about 49 private passenger cars per 1,000 inhabitants, which is quite low compared to European benchmarks but rapidly increasing due to the fast economic growth. Road transport accounted for 54% of all freight in 2003, up from about 48% in 1999. International highways Main highways carrying international traffic are the Baku-Alat-Ganja-Qazakh-Georgian Border corridor (Azerbaijani section of TRACECA corridor) with a length of 503 km and the so-called North-South Transport Corridor that stretches out from the Russian to the Iranian border along 521 km. Road connections are disrupted with Armenia because of the unresolved conflict regarding the possession of the Nagorno-Karabakh. Travel between the mainland and the detached exclave of Nakhchivan is made by air or by road through Iran. Nakhchivan has a 9-kilometre strategic border with Turkey. Pipelines Baku is the centre of major oil- and gas-producing regions and major long-distance pipelines radiate from the region's oil fields to all neighbouring areas. Pipelines are generally high-capacity lines and have diameters of either 1,020 or 1,220 millimetres. The main petroleum pipeline was completed in 2005 under American pressure to limit Russian and Iranian influence in the area. It runs from Baku via Tbilisi to Ceyhan in Turkey, therefore the acronym BTC pipeline. It made