(a) If a municipality erects or maintains a traffic signal or sign without meeting the requirements of this chapter, the district or county attorney of the county where the signal or sign is located shall bring a suit to enjoin the erection and maintenance of the signal or sign.
(b) If the district or county attorney does not institute a suit under Subsection (a) within 15 days after the date a request to do so is received from a resident of the state, any state resident may institute and prosecute the suit.