Following motorway exhaust's hot inside creating accident (6)
I believe the answer is:
mishap
'accident' is the definition.
(mishap is a kind of accident)
'following motorway exhaust's hot inside' is the wordplay.
'following' says to put letters next to each other.
'motorway' becomes 'mi' (resembles M1, English motorway).
'exhaust' becomes 'sap' (sapping is a kind of exhausting).
'hot' becomes 'h'.
'inside' indicates putting letters inside.
'sap' going around 'h' is 'shap'.
'mi' put next to 'shap' is 'MISHAP'.
'creating' acts as a link.
(Other definitions for mishap that I've seen before include "Accident, unlucky happening" , "An accident, piece of bad luck" , "Blow" , "'Accident, bad luck (6)'" , "Stroke of bad luck" .)