(a) No person shall operate a vehicle over any bridge or other elevated structure constituting a part of a highway at a speed which is greater than the maximum speed that can be maintained with safety to such bridge or structure, when such structure is posted with signs as provided in this section.
(b) The Department of Transportation upon request from any local authority shall, or upon its own initiative may, conduct an investigation of any bridge or other elevated structure constituting a part of a highway, and if it finds that such structure cannot with safety withstand traffic traveling at the speed otherwise permissible under this Traffic Code, the Department shall determine and declare the maximum speed of traffic which such structure can withstand, and shall cause or permit suitable signs stating such maximum speed to be erected and maintained at a distance of a least 100 feet before each end of the structure.
(c) Upon the trial of any person charged with a violation of this section, proof of such determination of the maximum speed by the Department and the existence of such signs shall constitute prima facie evidence of the maximum speed which can be maintained with safety to such bridge or structure.
(ORC 4511.23)