The Capitol-Medical Center Improvement and Zoning Commission, after adoption of a master comprehensive plan as hereinafter provided, shall have exclusive authority over the zoning and regulation of the utilization of all property in the above-described District and no planning or zoning commission of any subdivision of the state thereafter shall have any authority or jurisdiction within said area. The Commission also shall have authority to approve or disapprove the location and design of any improvements hereafter to be placed upon any land within said District, and no improvement hereafter shall be placed upon any land within said District, unless the location and design thereof shall be approved by said Commission. The word “improvements” as used in Sections 82.1 through 83.11 of this title shall include but not be limited to (1) buildings, including additions to and alterations thereof, (2) highways and thoroughfares, and access facilities thereto, (3) parking lots and facilities, and (4) all other construction or erections whatsoever, except that the word “improvements” shall not include existing municipal streets, alleys or utility services, nor the maintenance or improvement thereof, except insofar as the same serve state buildings or are located upon state land.