605 ILCS 5/10-1001

The Department shall repair, maintain, operate, control and preserve every covered bridge (and the abutments and approaches thereof) in this State, meaning every structure which spans a watercourse, chasm, ravine, road or railroad in or forming a boundary line of this State and affording passage from one bank or side thereof to the other, and which is enclosed in such manner as to prevent a clear, unimpeded view of the interior thereof from the top or longitudinal sides thereof.