To me, a freeway is 3-4 lanes with the big green signs showing you which off ramp is coming up,highway (because it's not like the freeways in LA and surrounding, which is what i think of when i'm thinking freeway)
A highway is usually one lane each way (with occasional passing lanes) with no lights or stop signs, and only a very small sign saying which town turn-off is next.
Once again showing regional differences.