Okla. Stat. tit. 69, § 69-655: County route markers

The board of county commissioners in each county may, within one

(1) year after the designation of the county primary road system in

that county, locate, erect and thereafter maintain markers

designating those routes classified as county primary roads.

Markers shall bear the cardinal number or other identification

assigned the particular route on which the marker is erected and

shall indicate the name of the county. The responsibility for

devising a practical, systematic county primary route numbering

scheme, including the configuration of the identifying device,

readily lending itself to functional implementation is vested and

imposed jointly on representatives of the Oklahoma Cooperative

Circuit Engineering Districts Board and the Department of

Transportation. The scheme shall be so devised as to offer

intracounty and intercounty road users a convenient means of

identifying and using the county primary road system and shall

provide for continuous numbering of routes crossing county

boundaries. The Department of Transportation is hereby authorized

to negotiate with the counties, on a statewide basis, to manufacture

and provide the markers on a materials plus cost basis.