Screw up road's name (9)
I believe the answer is:
mishandle
'screw up' is the definition.
(synonyms)
'road's name' is the wordplay.
'road's' becomes 'MI's' (resembles M1 motorway).
'name' becomes 'handle' (a handle is a name).
'mis'+'handle'='MISHANDLE'
(Other definitions for mishandle that I've seen before include "Badly judge" , "Wrongly manage" , "Maltreat" , "Fumble" , "Bungle" .)