Nothing contained in this act shall be construed as allowing an action or recovery against the state or any of its officers or employees on a claim or cause of action founded upon any loss occurring from a defect or dangerous condition on any road, street or highway which was in existence, whether known or unknown:
To the extent that the state is required by law to maintain a road, street, or highway within the territorial limits of a political subdivision, the political subdivision shall not be liable for any loss occurring from a defect or dangerous condition in the area required to be maintained by the state.
Okla. Stat. tit. 51, § 155.1