US 16, Rapid City, SD and Buffalo Gap
Dual unit distance signs on U.S. Highway 16 southwest of Rapid City SD. Left photo, September 2004; right photo, July 2006 by Jim Elwell.
Dual unit speed limit signs on U.S. Highway 16 southwest of Rapid City SD and at Buffalo Gap National Grassland, east of Rapid City. The metric speed limits on these signs should have been rounded to the nearest 5 km/h — 48 km/h should be 50 km/h, 72 km/h should be 70 km/h, and 88 km/h should be 90 km/h. Top photos, September 2004; bottom photo, July 2006 by Jim Elwell.