The board of township supervisors shall post signs on a minimum maintenance road to notify the motoring public that it is a minimum maintenance road and that the public travels on the road at its own risk. The signs shall be posted at the entry points to and at regular intervals along a minimum maintenance road. A properly posted sign shall be prima facie evidence that adequate notice of a minimum maintenance road has been given to the motoring public.
SDCL 31-13-1.2