Enactment of a TAD typically requires approval of all local governments who will be giving-up taxes, thus a project within a municipality will also require approval of the county's commission (or its local equivalent), and the board of the school district, in addition to the city council and possibly township board of supervisors (if applicable).
This differs from an improvement district, which the property owners agree to pay extra for improvements. That is only an option for an area which is already in good economic health.