Wasn't Bangalore-Tumkur road already a toll road? I had traveled in 2007 and I remember paying toll fee.
This new road starts from Gorguntepalya (near CMTI/Ring Road junction) and goes up to Nelamangala. The existing toll starts after Nelamangla. The road was ready long back but was not opened, because the toll was not finalised. Thankfully that is done, so the road should be opened soon.
If opened, this new flyover/toll road will hopefully decongest NH4
BTW : The existing road remains, this is optional for those who are ready to pay the toll - a concern is that heavy vehicles may continue to ply the old road, continuing the traffic chaos. Hope that doesn't happen!!!