Drive up motorway back to university (7)
I believe the answer is:
impulse
'drive' is the definition.
(I know that impulse is a type of drive)
'up motorway back to university' is the wordplay.
'motorway' becomes 'MI' (resembles M1, English motorway).
'back' says the letters should be written backwards.
'to university' becomes 'lse' (London School of Economics).
'up'+'mi'='upmi'
'upmi' backwards is 'impu'.
'impu'+'lse'='IMPULSE'
(Other definitions for impulse that I've seen before include "Instinctive motive" , "Impel us with sudden urge" , "Maybe unthinking urge" , "A push; whim" , "Impetus - whim" .)