Minn. Stat. § 165.05
Any railroad bridge hereafter constructed or substantially reconstructed over a public highway including city streets, shall be constructed so as to leave a clear opening for the highway at least four feet wider than the surfaced portion of the highway, but in no event less than 28 feet wide; provided that the requirement that the clear opening for the highway be at least four feet wider than the surfaced portion of the highway may be modified by the commissioner in accordance with plans approved by the commissioner.
Such bridge shall provide at least 16 feet clear space from the surface of the highway to the bottom of the bridge, except that such clear space under any bridge over roads other than those on the state trunk highway system or the interstate highway system shall be not less than 14 feet unless a lesser clear space is approved by the commissioner.
Minn. Stat. § 165.05
1959 c 500 art 6 s 5; 1963 c 242 s 1; 1973 c 123 art 5 s 7; 1986 c 444