National Highways Authority Of India [NHAI] — Roads and charging toll

I really fail to understand the collection of toll at nh67 between trichy and karur. Infact twice met with accident due to poor maintanace of roads. Basically this road is not four lane then why toll being collected. Please explain under what conditions the toll being collected when the roads are not four lane and also in many places that too whereever sand lorries branching places. Please explain with proper details from the basics.