2009 AASHTO submissions (the most recent changes to those routes):
http://sp.route.transportation.org/Documents/US85_Colorado.pdfhttp://sp.route.transportation.org/Documents/US87_Colorado.pdfFirst of all, US 87 should take the same route as US 85 in Colorado Springs. Once upon a time it was signed on the surface alignment, and in 2009 85 and 87 were partially moved together, and kept on the rest of the surface alignment (with a ducking fumb gap at the overpass north of exit 135, but we rightly ignore that for 85).
Pages 7-8 of each application includes the log, which match south of Castle Rock. Notably, 85/87 leaves 25 in Walsenburg, instead following the business route. This is not signed, but neither is the route via I-25.
So there are two issues here:
*87 should use the same route as 85 through Colorado Springs.
*Should 85 and 87 follow 25 Business through Walsenburg?