Main road can be a nuisance (4)
I believe the answer is:
drag
This clue is a double definition.
'main road' is the first definition.
(informal term for a road)
'a nuisance' is the second definition.
(thesaurus)
'can be' acts as a link.
(Other definitions for drag that I've seen before include "Draw - transvestite attire" , "Transvestite's garb" , "(Of time) pass slowly" , "What female impersonators assume" , "Yank" .)