70 ILCS 1505/7.03

The City of Chicago may, by ordinance, grant to Chicago Transit Authority the exclusive right to construct and operate any transportation facilities in, along, over, under, upon or across the boulevards, driveways and other property under its jurisdiction, in connection with, as extensions of or additions to the transportation system of said Authority, for a term equal to and concurrent with the term of any grant to said Authority by the City of Chicago to use the streets and other public places in the city for local transportation of passengers. Such ordinance shall not be effective until it has been accepted in writing by the Authority and the acceptance has been filed with the city clerk; provided, that nothing herein contained shall affect the validity of any right, privilege or permit granted by the Chicago Park District to Chicago Transit Authority prior to January 1, 1959.