After a municipal planning commission adopts plan of the municipality, no public works (street, public parks, buildings, structures, or public utilities) may be "constructed or authorized" unless the governing body or board (including the governing body or board of the state’s political subdivisions, such as county commissions) first asks for the planning commission’s approval of the public work’s location. If the planning commission disapproves, the commission must communicate its reasons to the chief legislative body over the project. The legislative body, by a vote of a majority of its membership, shall have the authority to overrule the planning commission and have the power to proceed with the public work. T.C.A. § 13-4-104. 

When constructing or providing maintenance on a public works project, a municipality is not required to have the architecture, engineering or landscape architecture plans, specifications and estimates made by a registered architect, registered engineer or registered landscape architect, if the "contemplated expenditure for the completed project does not exceed fifty thousand dollars ($50,000), and the work does not alter the structural, mechanical or electrical system of the project." T.C.A. § 62-2-107.