Some west coast classics that were missed:
Highway 99 in BC, 31A in BC, FS 25 in WA, Highway 242 in OR, highway 20 in WA, Highway 224/FS46 in OR.
Some of those aren't in the US, but let's face it, anyone who wants to claim that the US has the best roads probably hasn't travelled much, makes me think they've never heard of the Alps.