A transportation development district (“TDD”) is a separate political subdivision that may be created to fund, promote, plan, design , construct, improve, maintain and operate one or more transportation-related projects or to assist in such activity. A TDD can finance any transportation-related improvement, including any bridge, street, road, highway, access road, interchange, intersection, signing, signalization, parking lot, bus stop, station, garage, terminal, hanger, shelter, rest area, dock, wharf, lake or river port, airport, railroad, light rail, or other mass transit and any similar or related improvement or infrastructure. §§ 238.200 – 238.275 RSMO

A CID is different from a TDD. A TDD can only finance transportation-related improvements, while a CID can finance a wide-array of public improvements and services. A TDD can finance improvements that benefit the property within the boundaries; a CID generally cannot spend money on projects outside of its boundaries. TDD bonds can have a 40-year maturity, while CID bonds are generally limited to 20 years.