sentences:  An additional 28 mainline bridges were identified for not meeting the minimum horizontal clearance of .Most – if not all – of the aforementioned bridges were built during construction of the parkways in the 1960s and are nearing the end of their serviceable lifespans and are due to be replaced.The main issues concerning the 16 interchanges in SIU 5 were short acceleration/deceleration lanes (the average is while Interstate standards mandate ), and tight curve radii at interchanges with loop ramps.