605 ILCS 5/6-512
For the purpose of constructing, maintaining and repairing county unit district roads, bridges and drainage structures and the acquisition, maintenance, housing and repair of machinery and equipment, the county board, in any county in which a county unit road district is established, may levy annual separate taxes upon all taxable property of the county to be known as the "County Unit Road District Road Tax" and the "County Unit Road District Bridge Tax". Such taxes shall be levied and collected as other county taxes, but the road district taxes shall be in addition to the maximum of all other county taxes which the county is now or may hereafter be authorized by law to levy. The tax levies authorized in this Section shall not be extended in counties having less than 1,000,000 inhabitants at a rate in excess of .165% for the road tax, unless the maximum rate has been increased as provided in Section 6-512.1, and .05% for the bridge tax, both figures based on the value of all the taxable property within the county, as equalized or assessed by the Department of Revenue, or .01% in counties having 1,000,000 or more inhabitants, of the value, as equalized or assessed by the Department of Revenue, of all taxable property within the county; however, 1/2 of the County Unit Road District Road tax levied under this Section, on property lying within a municipality in which the streets and alleys are under the care of the municipality, shall, when collected, be paid over to the treasurer of the municipality to be appropriated to the improvement of roads, streets and bridges therein. In determining the amount of tax necessary to be raised and levied, the county board shall state separately the several amounts to be raised and levied for the construction of roads, the construction and maintenance of bridges and drainage structures, the purchase of machinery, the repair of machinery, the oiling of roads and the prevention and extirpation of weeds.
All tax moneys collected as a result of the levies authorized by this Section shall be deposited in separate county unit road district accounts known, respectively, as the "county unit road district road fund" and the "county unit road district bridge and drainage fund". The county treasurer shall be custodian of these funds, but the road district funds shall be maintained separate and apart from the general county fund.
605 ILCS 5/6-512