Honestly,I'm not really sure.The engineer's had their way of thinking I guess. One of the rumors was that the culvert bridge,built south of the SR58 crossing, was actually built higher than they thought/planned and that threw the grade off there.Not sure if it is true or not,but that was going around for awhile.The original grade appeared to have been just about as steep though in that spot. Of course,Indiana is known for several steep but short grades.