S.D. Codified Laws § 49-16A-89.2
Any railroad tracks over which an operating train travels which crosses a portion of the state trunk highway system, as defined in chapter 31-4, shall have a crossing alarm or a lighting device, or both, to alert the public of approaching trains and to notify the public of trains crossing the highway. The crossing alarm or lighting device shall be in place by December 31, 1998. The Department of Transportation shall decide the method which is most suitable for the protection of the public. The Department of Transportation shall use any federal highway safety funds to pay for the crossing alarms and lighting devices. However, if federal highway safety funds are not available, the railroad owning or operating the tracks is liable for the expenses of the crossing alarm or lighting device.
SDCL 49-16A-89.2