55 ILCS 5/5-14006
In any county with a population not in excess of 500,000 located in the area served by the Northeastern Illinois Metropolitan Area Planning Commission any planning commission created under the provisions of this Division may prepare and recommend to the county board of such county a comprehensive plan of public improvements looking to the present and future development of the region for the planning of which it was created. The plan or plans when adopted by the county board shall be designated as the official plan, or part thereof, of that county. Such plan or plans may be adopted in whole or in separate geographical or functional parts, each of which, when adopted, shall be the official plan or part thereof, of that county. Thereafter, from time to time, the planning commission may recommend changes in the official plan or any part thereof. To provide for the health, safety, comfort and convenience of the inhabitants of the county, such plans may establish reasonable standards of design for subdivisions and for resubdivisions of unimproved land and areas subject to redevelopment, including reasonable requirements for public streets, alleys, ways for public service facilities, storm or flood water runoff channels and basins, parks, playgrounds, school grounds, and other public grounds.
55 ILCS 5/5-14006