The amount a Tennessee county contributes to a state highway project depends entirely on the classification of the road and the specific statutory program used to fund it.
Here is how the Tennessee Department of Transportation (TDOT) and state law break down local financial responsibilities:
1. Standard State Highways & Interstates (0% Mandated Local Match)
By default, if a road is designated as a standard State Highway or Interstate, the State of Tennessee bears 100% of the cost for design, right-of-way acquisition, construction, and ongoing maintenance.
Major regional projects—such as the Pellissippi Parkway Extension (SR 162) and the Alcoa Highway (SR 115) relocation—fall into this category. They are funded through a combination of federal grants and state legislation (like the IMPROVE Act). While local county tax dollars are not required to build them, a county commission can occasionally vote to volunteer local funds to advance a project’s timeline, though they are not statutorily obligated to do so.
2. State-Aid Highway Program (2% to 25% Match)
This program is for local county roads that require construction, planning, or paving, but are designated as part of the “State-Aid” network.
- The Default: State law (T.C.A. § 54-4-404) generally requires a 25% local match from the county.
- The Exception: The “County Road Relief Act of 2015” amended this to require counties to provide a minimum of just 2% of the project cost. Crucially, this 2% does not have to be hard cash; it can be met through “in-kind” contributions, such as using the county highway department’s own labor or equipment.
3. Local Interstate Connector Program (50% Match)
If a county explicitly requests a new connector route to link existing local roads to an interstate or a fully controlled-access highway, the financial burden shifts significantly. Under T.C.A. § 54-5-507:
- The county must agree to a 50/50 split for the engineering, right-of-way, and construction phases.
- The county must deposit its 50% share of the engineering costs before TDOT will even begin. The same upfront deposit rule applies before the right-of-way and construction phases can commence.
- Once completed, the county must assume 100% of the maintenance costs for the connector.
4. Grant-Specific Matches (10% to 50% Match)
If a county is applying for specific infrastructure or economic development grants that involve state roadways, the match is determined by the specific grant guidelines and often the county’s economic status:
- Transportation Alternatives (TA) Grants: Typically require an 80% State / 20% Local split.
- Appalachian Regional Commission (ARC) Grants: The required local match is based on the county’s economic tier. “Distressed” counties only need to match 20%, “At-Risk” counties match 30%, and “Transitional” counties must match 50%.
Click link below to view WATE 6 On Your Side May 14, 2026 Video
Blount County residents fight Pellissippi Parkway Extension funding
This video provides relevant context on how local governments sometimes debate volunteering local tax dollars to accelerate the timeline of fully state-funded projects like the Pellissippi Parkway extension.