http://www.news.iowadot.gov/pim/2015/01/iowa-415-in-polk-county-feb-5-2015.html (http://www.news.iowadot.gov/pim/2015/01/iowa-415-in-polk-county-feb-5-2015.html)
Why?
http://bridgehunter.com/ia/polk/bh56094/
Presumably, IowaDOT thinks it's more cost effective to replace it with an intersection than to retain the existing interchange. Would certainly be cheaper...and looking at traffic volumes, there isn't a whole lot of turning traffic here.