105 ILCS 5/29-16
The school board of any school district which owns buses or other vehicular equipment for the transportation of pupils may rent such buses or equipment to the county board of any county in which it is situated to provide public transportation services pursuant to the "Downstate Public Transportation Act". The school board may rent such buses and equipment to the county board only for use during times when such buses or equipment are not needed for transporting pupils of the school district. A school board renting school buses or other vehicular equipment under this Section shall make a charge for furnishing such buses or other vehicular equipment in an amount not less than the cost thereof, including a reasonable allowance for the depreciation of each vehicle used.
This amendatory Act is not a limitation upon the contractual and associational powers granted by Section 10 of Article VII of the Constitution.
105 ILCS 5/29-16