70 ILCS 1225/1
In all cases where any board of park commissioners has selected and taken any street or part thereof under the provisions of an act of the General Assembly entitled, "An Act to enable park commissioners or corporate authorities to take, regulate, control and improve public streets leading to public parks, to pay for the improvement thereof and in that behalf to make and collect a special assessment or special tax on contiguous property," and any part or portion of said street so selected and taken has not been legally laid out or dedicated to the uniform width of one hundred feet, the said board of park commissioners shall have the power to widen said street or the part of said street so selected and taken to the uniform width of one hundred feet: Provided, that some portion of each mile of said street, or the part thereof so selected and taken, shall be of the width of one hundred feet at the time of such selection and taking.
70 ILCS 1225/1