 As a part of the European route E75 and Pan-European corridor X, connecting 4 of 5 largest Serbian cities (Belgrade, Novi Sad, Niš and Subotica), it is the most vital part of the Serbian road network.The northern section (Hungarian border – Subotica – Novi Sad – Belgrade) is 172 km long and was built between 1971 and 2013.The first subsection of this section to be opened is the Belgrade (Batajnica) – Novi Sad stretch.