road test vs trial

road test and trial both are nouns.

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

As nouns, trial is a hypernym of road test; that is, trial is a word with a broader meaning than road test:

Other hypernyms of road test include test, trial run, tryout.

road test (noun)	trial (noun)
a test to insure that a vehicle is roadworthy	the act of testing something
	(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