Car shortly occupied by a new driver (6)
I believe the answer is:
saloon
'car' is the definition.
(I've seen this before)
'shortly occupied by a new driver' is the wordplay.
'shortly' becomes 'soon' (synonyms).
'occupied by' is an insertion indicator (inserted letters occupy or enter the word).
'new driver' becomes 'l' (as in a learner driver with L-plates on their car).
'a'+'l'='al'
'soon' going around 'al' is 'SALOON'.
(Other definitions for saloon that I've seen before include "Car with separate boot" , "Large public room" , "Describing a bar - describing a car" , "US bar - type of car" , "Lounge bar" .)