Motorway bound to include coming accident (12)
I believe the answer is:
misadventure
'accident' is the definition.
(I know that accident can be written as misadventure)
'motorway bound to include coming' is the wordplay.
'motorway' becomes 'MI' (resembles M1, English motorway).
'bound to' becomes 'sure' (synonyms).
'include' means one lot of letters goes inside another.
'coming' becomes 'advent' (advent is the arrival or coming of something).
'sure' enclosing 'advent' is 'sadventure'.
'mi'+'sadventure'='MISADVENTURE'
(Other definitions for misadventure that I've seen before include "Bad luck; accidental killing" , "Unfortunate incident" , "Accident" , "disaster" , "Mishap" .)