I mean, the only states that have worked on it are SD and NE. CO doesn't seem to care (having been on CO 71, upgrading it would be really easy since there's nothing there, but there's also nothing there to upgrade for (traffic didn't seem too heavy)). SD upgraded it to four lanes all the way to the NE border, even though NE thought it was going to be 2-lane south of Hot Springs (see page 3 of this
document). So what we have right now (and this'll probably stay this way unless the politicians in power change (i.e. someone from Eastern CO or the Panhandle becomes governor)) is nice 70-mph 4-lane road from Rapid to the SD-NE border, 2-lane from the border to Alliance, 4-lane from Alliance to Kimball, and 2-lane the rest of the way. Since it's probably not ever going to be a cohesive route, it doesn't necessitate a singular number. In the NE/CO part, the route follows MSR 71, but that goes north from Scottsbluff/Gering while the expressway route heads east.