605 ILCS 5/8-105
In connection with the development of any freeway, the Department, the county board, or the corporate authorities of any municipality, as the case may be, is authorized, when traffic conditions justify, to lay out and construct local service drives or to designate existing highways or streets as local service drives to provide access to the freeway from adjacent areas at entrances provided for that purpose by the Department, county board, or the corporate authorities of any municipality or to provide access to any existing highway, road, street, alley or other public way from adjacent areas. Such local service drives shall be of appropriate design and construction and shall be separated from the freeway by parkways, curbs or other effective devices.
605 ILCS 5/8-105