70 ILCS 1260/1
That whenever any boulevard or parkway under the control of any public park commissioners is in need of improvements or repairs, it shall be competent for said park commissioners to make such improvements or repairs; or whenever any public street, avenue or alley under the control of any city, town or village adjoining any public park, or pleasure ground under the control of any public park commissioners is in need of improvements or repairs, it shall be competent for said park commissioners and said city, town or village, from time to time, to enter into an agreement for the payment to such city, town or village, by such park commissioners, of such portion of the cost of the improvement or repair of such public street, avenue or alley, as may in the judgment of said commissioners be of benefit to said park or pleasure ground, or to enter into an agreement for the making of such portion of the improvements or repairs by said park commissioners to any such public street, avenue or alley adjoining such public park or pleasure ground.
70 ILCS 1260/1