As part of the extension of Suzhou South-Ring Expressway, Dushu Lake highway tunnel has started works officially in mid May in Suzhou Industrial Park, which will become China's longest urban highway tunnel with 3.43km in length.

The extension works of Suzhou South-Ring Expressway starts from the southeast overpass and ends at Dushu Lake district, totaling up to 7.37km, consisting of a 3.43km long viaduct in the west, a 3.46km long tunnel under Dushu Lake in the east and a 0.48km long connecting line.