230.245.  Priority of roads by usage. — 1.  In establishing the comprehensive road plan required by sections 230.200 to 230.260, priority in construction, reconstruction, improvement, restoration and maintenance of roads shall be given in the following order:

  (1)  County roads presently used for school bus routes, mail routes and milk routes;

  (2)  County roads now used for any two of the purposes named in subdivision (1) above;

  (3)  County roads now used for any one of the purposes named in subdivision (1) above;

  (4)  County roads which may be used if improved or restored for a school bus route, mail route, or milk route;

  (5)  The construction of county roads which may be used for a school bus route, mail route or milk route;

  (6)  Any other county road containing a live rural unit, as defined in subsection 2 of this section, if consideration is given to the number of live rural units served by the road, and the amount of traffic on the road.

  2.  The following terms as used in sections 230.200 to 230.260 mean:

  (1)  "County roads", all public roads located within the county, except roads or highways constructed or maintained by the state transportation department or by the federal government, and except roads, streets, or highways in incorporated villages, towns, or cities;

  (2)  "Live rural unit", any church, school, dwelling, or farm.