(a) The commissioners court by order shall specify:
(1) the time and manner of applying for a business sign on a motorist information panel;
(2) the form of and required information for an application; and
(3) a reasonable annual fee for each business sign on the panel.
(b) To advertise on a motorist information panel, a person must apply to the commissioners court. The person shall comply with each order adopted by the commissioners court regarding business signs.