Okla. Stat. tit. 69 § 654
The boards of county commissioners of the various counties in this state shall adopt a system of county highways and public roads which shall constitute the county primary road system of their respective counties. Said system shall consist of functionally classified county collector routes as determined by the Department of Transportation in cooperation with the various boards of county commissioners and approved by the Federal Highway Administration.
In constructing and maintaining the various routes comprising the county primary road system, county officials shall take into consideration the relative traffic volumes existing on the various segments of such system in the county, population, industrial and marketing centers, and connections with improved segments of the respective county primary road systems in adjoining counties, the state highway system and the city street system.
Okla. Stat. tit. 69, § 654