Concessionaire Toll Agreement with the Govt is one sided.

The recent reminder by Works Minister SamyVellu that road toll will have to be increased soon doesnt make sense.Does the govt toll agreement with the Toll concesinaires provide an iron clad guarantee that they will constantly make consistently good profit over the duration of the toll agreement?
Why is there so much secrecy in the toll agreemnt?To avoid unfair insinuation and aspersion on the govt officials and Minister given the task of making the agreemnt with the Toll concessionaires,would it not be proper and transparent that those agreements be made public so that we can see if everything is above board.
The public perception is that the agreement is one sided and quite rightly so.Why must the govt give a guarantee that compensation will be paid to the concessionaire if toll is not allowed to increase after a period of years?Going by logic, the number of vehicles would increase every year and by that deduction toll would also correspondingly increase.If that be the case then why the necessity for an increase in toll or the need to compensate the concessionaire? The increase in the number of vehicles would have adequately compensated the concessionaire without any increase in the toll.
I doubt the public would accept any toll increase in the absence of any proper disclosure of the reasons for such an increase.