S.D. Codified Laws § 31-27-2
The Department of Transportation may determine, order, and prescribe in accordance with the plans and specifications to be approved by it, the reasonable manner, including the particular point of crossing, at which the tracks or other facilities of any line of railroad may be constructed across the tracks or any other facilities of any other line of railroad, or of any street, or highway, at grade, or above or below grade, or at the same or different levels, or at which the tracks or other facilities of any railroad company or companies may be constructed across the track or facilities of any other railroad company, or across any public highway, street at grade, or above or below grade, or at which any public highway may be constructed across the tracks or other facilities of any railroad company at grade or above or below grade; and may determine, order, and prescribe the terms and conditions of installation and operation, maintenance, and protection of all such crossings, which may be constructed, including any watchman thereat, or the installation and regulation of lights, blocks, interlocking, or other systems, or devices of signaling, safety appliance devices, or such other means or instrumentalities as the department determines reasonable and necessary to the end, intent, and purpose that accidents may be prevented and the safety of the public promoted.
SDCL 31-27-2