SDCL § 31-33-2: Requirement for establishment of arterial street system.

An arterial street system shall be designated by the governing body of each municipality of this state having a population of five thousand or more according to the last federal census, provided, however, that any municipality of the state with less than five thousand population may also establish an arterial street system should said municipality find such action advantageous in planning, constructing, maintaining, and administrating the highways and streets under its jurisdiction.