This is an excerpt from a circa 1961 Sebastian County road map, courtesy of the Arkansas State Highway Commission (now ARDOT), It shows a proposed relocation of US 71 that would bypass the section of highway that is now AR 10S and downtown Greenwood, connecting to AR 10 just west of the then-current highway 71. Interestingly enough, the narrow, winding, hilly, dangerous old US 71 routing over Backbone Mountain would have remained a part of US 71. This alignment was never built, and in its place a western bypass of Greenwood was built, bypassing what is now AR 10S and Backbone Mountain. That section, which goes through a very impressive road cut that looks like a set of stairs for a giant, is now 4 lanes divided as is US 71 all the way to Fort Smith. The expressway ends at the southern end of the Greenwood bypass, where it meets the old Backbone Mountain highway. I wonder why they were considering this routing in the first place, and what made them change their minds.
