Car's first off, about to take advantage of high road (8)
I believe the answer is:
causeway
'high road' is the definition.
'causeway' can be an answer for 'road' (thesaurus). I'm unsure of the 'high' bit.
'car's first off about to take advantage of' is the wordplay.
'car's first' becomes 'c' (ast letter of 'car').
'off' becomes 'away' (synonyms).
'about' is an insertion indicator.
'to take advantage of' becomes 'use' (use can mean to exploit or take advantage).
'away' going around 'use' is 'auseway'.
'c'+'auseway'='CAUSEWAY'
Can you help me to learn more?
(Other definitions for causeway that I've seen before include "Raised road across water - may be a Giant's" , "Raised road through a marsh" , "Raised road or track" , "Raised road across wet area" , "Raised road crossing shallow water" .)