Minn. Stat. § 161.30
The commissioner shall adopt a suitable marking design with which the commissioner shall mark or blaze the trunk highway routes, and as the definite final location of each route is opened to traffic the markings shall be changed to such location.
In order to coordinate the markings of the various existing routes, together with the new routes which have been or may be added, and in order to avoid duplication in numbers used on interstate routes, the commissioner may revise and consolidate the marking and numbering of the routes within the system from time to time. Upon revising the marking or numbering the commissioner shall prepare a map showing the existing routes and identifying numbers and the routes and identifying numbers or design of the revised system. This map shall be authenticated by a certificate of the commissioner certifying the same as being the map showing the revised markings under the provisions of this section. This map and certificate shall be filed in the office of the commissioner and thereafter shall govern the identification of the several routes or portions thereof in the trunk highway system and all proceedings, records, and accounts thereafter shall be governed accordingly. Proceedings pending and under way at the time such map is filed shall cite both the old and the new identifications.
Minn. Stat. § 161.30
1959 c 500 art 2 s 30; 1986 c 444