After motorway, turned up sideroad on the way to work (5,8)
I believe the answer is:
modus operandi
'way to work' is the definition.
'after motorway turned up sideroad on' is the wordplay.
'after' means one lot of letters go next to another.
'motorway' becomes 'M' (as in motorway names - M1, M4 etc).
'turned' indicates an anagram.
'up'+'sideroad'+'on'='upsideroadon'
'upsideroadon' with letters rearranged gives 'odusoperandi'.
'm' next to 'odusoperandi' is 'MODUS OPERANDI'.
'the' is the link.
(Other definitions for modus operandi that I've seen before include "Classically typical style" , "way of doing things" , "Method of working" , "Particular way of doing something (Latin)" , "MO in full" .)