SMART stands for Stormwater Management and Road Tunnel. The 13.2m diameter tunnel consists of a 9.7km storm water bypass tunnel, with a 4km dual-deck motorway within the storm water tunnel. The main purpose of SMART is to solve the problem of flash flooding in Kuala Lumpur from the Sungai Klang and Kerayong rivers and also to reduce traffic jams during the daily rush hour