605 ILCS 5/5-701.9

Any county board may also use motor fuel tax money allotted to it for constructing or maintaining, or both, a county garage for the servicing, maintenance or storage of vehicles or equipment used in the construction or maintenance of county or state highways. The county board of any county with a population of 1,000,000 or more may also use motor fuel tax money for constructing or maintaining auxiliary office space.