The portion of State Highway 13 within Polk County from the^* intersection of^** State Highway 83 to the^* intersection of^** State Highway Y in Polk County shall be designated the “Rick Seiner Memorial Highway”. The department of transportation shall erect and maintain appropriate signs commemorating this portion of highway and designating such highway designation, with the cost to be paid for by private donation. All signage shall be paid for and maintained through private sources and shall meet appropriate specifications as set forth by the department of transportation.