trial vs road test

trial and road test both are nouns.

Word	Noun	Adjective	Verb	Adverb
trial	Yes	No	No	No
road test	Yes	No	No	No

As nouns, road test is a hyponym of trial; that is, road test is a word with a more specific, narrower meaning than trial:

Other hyponyms of trial include field test, field trial, alpha test, beta test, trial balloon.

trial (noun)	road test (noun)
the act of testing something	a test to insure that a vehicle is roadworthy
(law) the determination of a person's innocence or guilt by due process of law
the act of undergoing testing
trying something to find out about it
an annoying or frustrating or catastrophic event
(sports) a preliminary competition to determine qualifications