Tennessee Code Title 54. Highways, Bridges and Ferries § 54-4-507

(a) The state share payable for a project undertaken pursuant to this part shall be no more than eighty percent (80%) of the approved project cost.

(b) The local government share shall be at least twenty percent (20%) of the approved project cost. This share may be provided by local government funds and in-kind project work approved by the commissioner, or either of them, wholly or partly.

(c) The percentage in subsections (a) and (b) shall also apply to any unexpended balance from appropriations prior to 2004 that are not subject to a written agreement between the local government and the department. In the event there exists a written agreement between the department and the local government, then the percentage contained in the agreement shall continue to apply.

(d) If any county has an unexpended balance of funds that have accrued in the state treasury and that are available for the benefit of the county under this part, then the county may use the unexpended balance, in whole or in part, to provide a portion of the local government share required by subsection (b); provided, that the county shall provide at least two percent (2%) of the approved project costs from county funds or in-kind project work approved by the commissioner of transportation, or both.