The board of supervisors of each county, now having full jurisdiction over all roads, ferries, and bridges in its respective county not maintained as state highways, is hereby fully authorized and empowered to construct and maintain the same (including designated state highways not yet taken over by the highway department); and all such roads under the jurisdiction of the several boards of supervisors are hereby designated, defined, and declared to be either (a) "feeder" or "local farm roads" or (b) "state aid roads."
State aid roads are hereby defined as that group or class of roads composing the main collector and distributor routes feeding into local trade areas or into the state highway network, which are not designated as state highways by the Legislature, and particularly those essential to the conservation and development of natural resources, of economic and social value, and encouraging desirable land utilization, having in addition the following characteristics, to wit: roads (including bridges and ferries) which
Connect communities within the individual counties and with those of adjoining counties and/or which also connect with the state highway system to form a complete network of secondary or collector routes.
Carry heavy volumes of traffic serving most of the following interests of the counties, to wit:
The State Aid Engineer shall see that the criteria imposed herein are explicitly followed in the designation and in the construction of the state aid roads in each county. The State Aid Engineer shall promulgate regulations pursuant to the Administrative Procedures Act to require the development of a network of intercounty roads and to provide for a review process within the state aid division for the designation of said state aid roads. Such regulations shall also establish standards for state aid route designation. The State Aid Engineer is hereby authorized and directed to withhold funds from such counties until the state aid roads therein are designated and constructed according to the characteristics set forth herein.
All other roads under the jurisdiction of the several boards of supervisors are hereby declared to be "local farm roads" and not affected in anywise by this chapter.
State aid roads in the several counties shall be eligible for state aid in the manner and under the terms and conditions hereinafter set out. Local system roads (as defined in Section 65-18-3) in the several counties shall be eligible for state aid in the manner and under the terms and conditions set out in the Local System Road Program established in Sections 65-18-1 through 65-18-17. State aid, by way of funds to be expended on state aid roads and local system roads (as defined in Section 65-18-3), shall consist of any sum or sums provided by the Legislature to supplement funds furnished by the several counties for the purpose of constructing, improving, widening, straightening, surfacing, or reconstructing roads on the state aid system or for the purpose of the construction, reconstruction and paving of roads on the Local System Road Program, and shall be available to the several counties in such proportion as may be fixed and determined by law.