comprise of trunk and regional natural gas pipelines and a 450 million cubic metre underground gas storage facility at Banatski Dvor. In 2021, Balkan Stream gas pipeline opened through Serbia. Transport Serbia has a strategic transportation location since the country's backbone, Morava Valley, represents the easiest land route from continental Europe to Asia Minor and the Near East. Serbian road network carries the bulk of traffic in the country. Total length of roads is of which are "class-IA state roads" (i.e. motorways); are "class-IB state roads" (national roads); are "class-II state roads" (regional roads) and are "municipal roads". The road network, except for the most of class-IA roads, are of comparatively lower quality to the Western European standards because of lack of financial resources for their maintenance in the last 20 years. Over of new motorways were constructed in the last decade and additional are currently under construction: A5 motorway (from north of Kruševac to Čačak) and -long segment of A2 (between Čačak and Požega). Coach transport is very extensive: almost every place in the country is connected by bus, from largest cities to the villages; in addition there are international routes (mainly to countries of Western Europe with large Serb diaspora). Routes, both domestic and international, are served by more than hundred intercity coach services, biggest of which are Lasta and Niš-Ekspres. , there were 1,999,771 registered passenger cars or 1 passenger car per 3.5 inhabitants. Serbia has of rail tracks, of which are electrified and are double-track railroad. The major rail hub is Belgrade (and to a lesser degree Niš), while the most important railroads include: Belgrade–Subotica–Budapest (Hungary) (currently upgraded to high-speed status), Belgrade–Bar (Montenegro), Belgrade–Šid–Zagreb (Croatia)/Belgrade–Niš–Sofia (Bulgaria) (part of Pan-European Corridor X), and Niš–Thessaloniki (Greece). Some 75 km (46 mi) of new high-speed rail line between Belgrade and Novi Sad was opened in 2022 and additional 108 km (67 mi) from Novi Sad to Subotica and border with Hungary are currently under construction and due to open in 2025. Construction work for 212 km-long prolongation of the high-speed rail line to the south, to the city of Niš, is set to commence in 2024 and with its planned completion by the end of the decade four of country's five largest cities will be connected by the high-speed rail lines. Rail services are operated by Srbija Voz (passenger transport) and Srbija Kargo (freight transport). There are three airports