Yesterday I took a drive on US 138 from end-to-end, and noticed both Nebraska and Colorado repeatedly referred to it as a state highway in the field and Colorado also calling it SH-138 in a news release posted online. It felt like both states were making the "error" enough to not just be a simple mistake. I was wondering if anyone on the inside around here may be aware of a future possible axing of US 138.
I wouldn't read too much into that. CDOT and local agencies repeatedly and randomly refer to US highways as state highways around the state. Many counties don't draw the distinction on their street name signs either.