I was doing a little research of I-90 in South Dakota via Google Street View, when I noticed there appears to be a construction project west of Sturgis Road between south of the Tilford Rest Areas, and the vicinity of Exit 44 in Piedmont. I'm not sure I'll find it on South Dakota's DOT website, so I have to ask if anyone here knows what that project is all about.
http://rapidcityjournal.com/news/local/communities/sturgis/new-interstate-service-roads-going-in-at-piedmont/article_5a24646d-85ca-5292-9381-b26c8a304598.html
http://www.sddot.com/transportation/highways/planning/specialstudies/docs/03-241CorridorPreservReportfinal.pdf
To sum up: the whole point of it is to realign the service road west of the interstate so that it is farther away. This summer Exit 44 will be completely rebuilt (along with the interstate from mm 40 to 45 ish), and the old configuration had the service road much too close to the ramps.
Also it's been done for 8 months.