(a) In this section, "vehicle" means a device that is designed to transport persons or property and is self-propelled or propelled by external means.
(b) A person commits an offense if the person operates a vehicle on a sand dune seaward of the dune protection line as defined in Section 63.012, Natural Resources Code, except on a roadway designated by a subdivision of the state.
(c) An offense under this section is a Class C misdemeanor.