Why DBKL is not doing this to solve major traffic jam in KL?

If you're working or shopping or simply driving thru KL city center, I'm almost sure you have come across the infamous traffic gridlock at Bulatan Dato Onn, right under the flyover heading towards Loke Yew. 

Typical (daily) scenarios:

1. cars heading north (towards Sentul, Selayang etc.) from Jalan Kuching have to stop at traffic light before roundabout.
2. when cars from Jalan Kuching move, cars from Jalan Parlime entering the city will block.
3. then cars stops again in front of Bank Rakyat, when moving block by cars from Jalan Sultan Salahuddin, by the time you reach BNM it will take at least 10 minutes on a good day, some time I have time to get down and jog around the Bulatan ;)
4. Same issue for cars from Jalan Kinabalu trying to head south.

After driving, riding, walking thru this excreta situation for years, I wonder why DBKL have not created a simple solution right under the bridge?? A U-turn for light/small vehicle on both sides will solve most of the gridlock around the Bulatan (see picture above). To make things worse, place under bridge has some really unpleasant 'landscaping' crap, which is being enjoyed by drug addicts as their favorite sleepover location. DBKL is just across this traffic mess, I mean if they look out of their window, they can clearly see it, but why they have not done anything simple to solve this matter?

p/s DBKL spends a lot money to maintain the plants under the bridge, they have to water it even during monsoon rain, because the damn bridge covers the plant from rain and its elevated too!