travel vs on the road

travel and on the road both are nouns.

Word	Noun	Adjective	Verb	Adverb
travel	Yes	No	Yes	No
on the road	Yes	No	No	No

As nouns, on the road is a hyponym of travel; that is, on the road is a word with a more specific, narrower meaning than travel:

travel (noun)	on the road (noun)
the act of going from one place to another	travelling about
self-propelled movement
a movement through space that changes the location of something

travel (verb)	on the road (verb)
change location; move, travel, or proceed, also metaphorically
make a trip for pleasure
travel upon or across
undergo transportation as in a vehicle
undertake a journey or trip
travel from place to place, as for the purpose of finding work, preaching, or acting as a judge