Dandy in a vehicle on entering motorway (8)
I believe the answer is:
macaroni
'dandy' is the definition.
(I know that macaroni is a type of dandy)
'a vehicle on entering motorway' is the wordplay.
'vehicle' becomes 'car' (car is a kind of vehicle).
'entering' indicates putting letters inside.
'motorway' becomes 'MI' (resembles M1, English motorway).
'a'+'car'+'on'='acaron'
'acaron' put within 'mi' is 'MACARONI'.
'in' is the link.
(Other definitions for macaroni that I've seen before include "Tubed pasta" , "Italian fare" , "Alternative to 31 [TORTELLINI]" , "penguin?" , "Pasta variety, eighteenth century dandy" .)