Okla. Stat. tit. 17, § 17-82: Expense of crossings

The expense of construction and the maintenance of public

highway grade crossings shall be borne by the railroad or railway

company involved. For overgrade or undergrade public highway

crossings over or under steam or electric railroad or railway, the

assignment of cost and maintenance shall be left to the discretion

of the Corporation Commission; but in no event shall the city, town

or municipality be assessed with more than fifty percent (50%) of

the actual costs of such overgrade or undergrade crossings.