On the road, a dangerous gear change (4)
I believe the answer is:
rage
'on the road a dangerous' is the definition.
I can't judge whether this definition defines the answer.
'gear change' is the wordplay.
'change' indicates anagramming the letters.
'gear' anagrammed gives 'RAGE'.
Can you help me to learn more?
(Other definitions for rage that I've seen before include "Fad or anger" , "High dudgeon" , "Frenzy" , "spread rapidly" , "Fashionable" .)