Ohio Rev. Code § 5516.03
The director of transportation shall adopt, amend, and enforce rules, consistent with the customary use of outdoor advertising, the safety of the traveling public, and national policy as are necessary to carry out the provisions of this chapter. Such rules may include, but shall not be limited to, sizing, lighting, spacing, and such other conditions as may be necessary to promote the safety of the traveling public and effect the national policy. The rules shall be in addition to the provisions of municipal ordinances regulating advertising devices and shall not invalidate the provisions of any municipal ordinance that are equivalent to and consistent with the rules adopted by the director under this section. The director shall furnish a copy of such rules, without charge, to any person making a request therefor.
R.C. §5516.03