70 ILCS 1505/7
The Chicago Park District is vested with all powers heretofore vested in park districts or corporate authorities whose authority is abrogated by this Act or by the operation thereof. All powers now vested in such commissioners or districts with regard to the extension of parks, boulevards and driveways by reclaiming submerged lands and by the acquisition of riparian rights and shore lands shall hereafter be exercised by the Chicago Park District; provided, that the city shall exercise the power to operate, maintain and govern boulevards, driveways, roadways and highways used as thoroughfares for vehicular traffic into or within parks, including bridges, subways, viaducts and approaches appurtenant thereto as provided by "An Act in relation to an exchange of certain functions, property and personnel among cities and park districts having coextensive geographic areas and populations in excess of 500,000", approved July 5, 1957, including the duty of regulating traffic on such boulevards, driveways, roadways and highways. Such city shall provide police for the parks of the park district.
70 ILCS 1505/7