Tenn. Code § 13-3-105
From and after the time of the creation and defining by the department of economic and community development of a planning region, and the appointment by the department of a regional planning commission of such region, thenceforth the department of transportation or any other state department shall not agree to supply or appropriate money for the construction of any road, bridge, or other public structure within the region, nor shall any state department construct or contribute to the construction of any street, road or other public structure within any municipality in the region, nor shall any county lying wholly or partly within the region participate in the expenditure of the funds of any state department or be aided in the construction of any road, bridge, or other public structure within the region, nor shall state liability be incurred incident to the acquisition of rights-of-way or other property for any highway or other public improvement within the region, nor any other state aid be given for any road, bridge, building or other public structure within the region, until and unless such supply, appropriation, construction, contribution, participation, liability or aid has been submitted to the department of economic and community development and until the department has given and reported its judgment, opinion and recommendations thereon to the court, board, official or department having charge of such acquisition, supply, appropriation, contribution, participation, liability, aid, construction, or authorization; provided, that in the event that the department fails to make such report within thirty (30) days from and after the date of the submission to it, this requirement shall be deemed to have been waived; and in passing upon the question of its approval, the department may take into account the quality of the work of the regional planning commission; the object of this requirement being to promote the application of planning methods and principles in the location, character and extent of public works financed with the help of state aid.
T.C.A. § 13-3-105