In 1982, Jurong West New Town started expanding as Jurong West Extension, which saw the realignment of the PIE to make it go through the southern boundary of present-day NTU, while converting the former section into Jurong West Avenue 2 and renaming the original Upper Jurong Road into Jurong West Avenue 4. Pioneer Road was extended North wards from present-day Upper Jurong Road as Pioneer Road North to the new PIE exit, which signalled the start of the development of Jurong West Extension (Yunnan, Pioneer and Gek Poh). The N9 estate was the first to be built and the N6 estate was the last, in the early 2000s. The MRT Line was extended from Lakeside to Boon Lay in 1990 and again to Pioneer in 2009.