After any plan for major highways, or portion thereof, has been prepared by the county planning commission, filed and certified as provided in section 64.815, the county commission shall be authorized and empowered to establish, regulate and limit building or setback lines on the major highways outside the corporate limits of municipalities and to prohibit any new building being located within the building or setback lines, and to amend the regulations from time to time. All orders of the county commission relating to buildings or setback lines shall be entered of record and certified copies thereof shall be filed with the county planning commission, and in the office of the recorder of deeds.