BEIJING - China is aiming to upgrade its national expressway network over the next five years, said an official from the Ministry of Transport (MOT) Tuesday.

The expressway network comprises seven expressway roadways starting from the capital city Beijing, nine lines linking the country's south and the north, and 18 lines extending from the east regions to the west, Weng Mengyong, vice minister of the MOT said at a press briefing.

Weng said the country has 74,000 kilometers of expressways, the world's second longest after the United States. Of note, by the end of 2010 there were 33,000 km more than five years ago.

Also called motorways, an expressway in China refers to a dual carriageway (with two directions of traffic separated by a central strip) having limited access and grade separated junctions, with speed limits varying between 70km/h and 120km/h.