Whenever the board of county commissioners of any county now or hereafter having a population of one hundred seventy-five thousand (175,000) or more, shall adopt, by and with the approval of the secretary of transportation, a master, long range highway development plan based upon engineering surveys and traffic use and needs studies, and whenever the secretary shall determine and designate certain new routes or existing highways, forming a part of such county master highway development plan, are essential and important highways to connect with or provide necessary access highways to or from the state highway system in such counties, the boards of county commissioners of such counties, in its discretion, may authorize the preparation of preliminary plans and specifications for constructing, reconstructing, improving or repairing the major, arterial county highways, which project shall thereafter be designated as the master highway development plan for such counties and shall be completed within ten (10) years from the date of its adoption or approval by the voters of such counties.

The preliminary plans and specifications for such county master highway development plan shall be approved by the state transportation engineer, the county engineer and members of the boards of county commissioners of such counties and filed in the office of the county clerk of such counties. The cost of such preliminary plans and specifications may be paid from the road maintenance fund of such counties, even though such items were not budgeted in such year; and if the proposition calling the adoption and approval of such master highway development plan, is voted for affirmatively by a majority of the electors of such counties at a special election held for such purpose or at the general election, the cost of such preliminary plans and specifications may thereafter be included in the total cost of such plan or project to be paid for by the issuance of bonds.