Car of Italian, on vacation, entering motorway (4)
I believe the answer is:
mini
'car' is the definition.
(Mini Cooper)
'italian on vacation entering motorway' is the wordplay.
'on vacation' means to remove the middle letters (after the inside letters have vacated the word).
'entering' means one lot of letters goes inside another.
'motorway' becomes 'MI' (resembles M1, English motorway).
'italian' with its centre taken out is 'in'.
'in' placed within 'mi' is 'MINI'.
'of' acts as a link.
(Other definitions for mini that I've seen before include "type of garment" , "Cult British car" , "Car designed by Issigonis" , "(Car etc) of small size" , "Small (of car, skirt, disk,bar or series)" .)