605 ILCS 5/4-201.18
To acquire land adjacent to the right-of-way on a federal aid system outside the central business district in an urban area of 50,000 population or more as provided by the Federal Aid Road Act and to construct and operate a publicly owned parking facility thereon or within the right-of-way, including the use of air space above and below the established grade line of the highway pavement. Such parking facility shall be (1) based on a continuing comprehensive transportation planning process as defined in the Federal Aid Road Act, and (2) located and designed in conjunction with existing or planned public transportation facilities.
Fees charged for the use of such facility shall not be in excess of that amount required for maintenance and operation, including compensation to any person for operating such facility, and shall be used for such purposes before any other funds may be used for maintenance and operation.
Any federal aid project constructed under this Section may be constructed by agreement and jointly at the expense of the federal government and the State of Illinois or jointly at the expense of the federal government, the State of Illinois, a municipality or municipalities or a county or counties, in accordance with the provisions of the Federal Aid Road Act.
For the purposes of this Section, the term "parking facilities" shall include access roads, buildings, structures, equipment, improvements, and interests in the lands.
605 ILCS 5/4-201.18