A.   All highways, roads, paths and ways within the county not designated as federal, state, city or special highways, roads, paths or ways shall be under the direction and authority of the board of county commissioners. Such roads shall be constructed and maintained by or under the authority of the county commissioners from funds made available for that purpose, and the county commissioners shall have the authority to expend or by contract cause to be expended funds allocated to the county from the state road fund under rules mutually adopted by the county commissioners and the state road commission. The amount used annually from the state road fund for this purpose, together with amounts from other sources as may be made available, shall constitute the funds to be spent in constructing and maintaining class B roads within the county.
   B.   When, in the opinion of the county commissioners, the funds available for road purposes from sources other than the levy made against tangible property are adequate to properly construct and maintain the class B roads, the county may cease making a levy for county road purposes or, at its option, may use any portion of the class B road funds provided by Utah Code Annotated title 72, for the construction and maintenance of class A state roads by cooperative agreement with the state road commission. (1988 Code § 9.04.010)