 The route was first proposed in 1933 ; it would have traveled through <unk> and Wilson counties . Portions of the proposal were replaced by SH 97 by at least 1936 , while the rest was cancelled . State Highway 87 first followed the routing of SH 168 , but was moved by 1961 . A short railroad spur was built along the course of the route , and SH 168 was officially designated in 1986 . 
