At any time after receiving the report required by section 40-22.1-04, the governing body may direct the city auditor or other person, group, or other entity preparing the report to prepare detailed plans and specifications concerning the improvement. The plans and specifications must be approved by a resolution of the governing body of the municipality. The plans, specifications, and estimates are the property of the municipality and must be filed in the office of the city auditor and shall remain on file in that office subject to inspection by the public.