MUTCD: Orange construction speed limit signs are unenforceable

According to the federal Manual of Uniform Traffic Control Devices, CONSTRUCTION signs are orange diamonds specifically used only to WARN drivers about construction and work zone activity.  The orange speed limit signs with black lettering are warning signs and hence they are unenforceable by the traffic police department.  But they are recommended by Ohio Department of Transportation

Construction traffic sign

City of Solon installed 25 MPH regulatory speed limit signs to replace 35 MPH posted speed limit signs in a construction zone on Bainbridge Road.  Ohio Department of Transporation advised the City that the change cannot be made without a formal study.  Obviously, the City’s study could not justify the installation of 25MPH sign on the arterial Bainbridge Road and the 25 MPH speed limit signs had to be removed.