"State highway" means a highway under the jurisdiction of the Ohio Department of Transportation, outside the limits of municipal corporations, provided that the authority conferred upon the director of transportation in R.C. § 5511.01 to erect state highway route markers and signs directing traffic shall not be modified by R.C. §§ 4511.01 to 4511.79 and 4511.99.
(R.C. § 4511.01(II))