
I had the opportunity to use the Smart Tunnel recently, and managed to take some photos while in it. Drove slowly at about 40kph since there were very few cars in it.
The tunnel is quite unique since its primary focus is to divert flood water along a 10km route to holding basins. The tunnel consist of triple decker compartments – the top and the middle is for traffic (only one way traffic on each level), while the bottom compartment is the drain. When required, the tunnel can be closed and all the three levels flooded with water. The road itself is only about 3-4km long and is basically used to avoid the daily crawl along the main artery from the south towards KL city centre.
Source: Smart Tunnel website
The toll costs RM2 and there are three entry/exit points. One is at before Sg Besi toll (near the Airforce Airport). Another is at Jalan Tun Razak, just before Bulatan Kg Pandan (Pandan Roundabout) and the last one is at Jalan Davis, Bukit Bintang area, near the Berjaya Times Square.