Kentucky questions

[froggie]

They haven't done that since the 60s. I believe Oregon is the only state that still has such a dual numbering system.

Minnesota.  Which also has the Constitutional Routes...which are the routes required to be in the system per the state constitution, though MnDOT has some leeway in defining just which highway route the Constitutional Route follows.  For example, some of C.R. 1 follows I-35.