Benefit from having a commercial vehicle at the junction for a long time (9)
I believe the answer is:
advantage
'benefit' is the definition.
(I've seen this before)
'commercial vehicle at the junction for a long time' is the wordplay.
'commercial' becomes 'ad' (abbreviation for advertisement).
'vehicle at' becomes 'vant' (I can't justify this - if you can you should give a lot more credence to this answer).
'the junction' is a charade indicator (letters next to each other).
'for' says to put letters next to each other.
'a long time' becomes 'age' (an age is a period of time).
'ad'+'vant'+'age'='ADVANTAGE'
'from having a' is the link.
This may not be correct. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for advantage that I've seen before include "Asset" , "Benefit, profit" , "Superior or more favourable position" , "First point scored after deuce in tennis" , "Profit, tennis score" .)