Ohio Rev. Code § 4513.23: Rear view mirror.

(A) Every motor vehicle, motorcycle, and trackless trolley shall be equipped with a mirror so located as to reflect to the operator a view of the highway to the rear of such vehicle, motorcycle, or trackless trolley. Operators of vehicles, motorcycles, streetcars, and trackless trolleys shall have a clear and unobstructed view to the front and to both sides of their vehicles, motorcycles, streetcars, or trackless trolleys and shall have a clear view to the rear of their vehicles, motorcycles, streetcars, or trackless trolleys by mirror.

(B) Whoever violates this section is guilty of a minor misdemeanor.