Been wanting to ask this.

Pictures and examples would do greatly

shey google barnishe yu?

OK since google no dey ur phone op make I help u out
A national highway is one that connects regions of one state to some place in another state. They are maintained by the Central Government unlike State highways (connecting regions within a single state) which are under the control of the State government.

Coming to the difference between highways and expressways:

• A highway is a generic term given to roadways that are used to connect important cities, and usually have 4 lanes to provide for high speed traffic.

• An expressway is a high speed road with partial access and extra facilities like access ramps and lane dividers. It may or may not be part of a highway.
Source. https://www.google.com/url?sa=t&source=web&cd=2&ved=0ahUKEwiH-7fx6t3SAhWHCCwKHaq5A88QFggYMAE&url=https%3A%2F%2Fwww.quora.com%2FWhat-is-the-difference-between-national-highway-and-expressway&usg=AFQjCNFUOtuQofKsmeelPXthNG-t0h4DnQ&sig2=jEkCO1h4Tu4CtYdgnw1f1A

Here is the answer to your question

newyorks:
shey google barnishe yu?

Na Naija own I wanted Bros...Our things are just different here.