Line he's taken through favourite road enthused driver (10)
I believe the answer is:
petrolhead
'line he's taken through favourite road enthused driver' is the definition.
The definition suggests a singular noun which matches the answer.
'line he's taken through favourite road' is the wordplay.
'line' becomes 'l' (used when specifying particular lines from a poem).
'taken through' indicates putting letters inside.
'favourite' becomes 'pet' (synonyms).
'l'+'he'='lhe'
'pet'+'road'='petroad'
'lhe' inserted within 'petroad' is 'PETROLHEAD'.
Can you help me to learn more?
(Other definitions for petrolhead that I've seen before include "Motoring fanatic" , "Car lover" .)