Main road is nuisance (4)
I believe the answer is:
drag
I believe this is a double definition.
'main road' is the first definition.
(informal term for a road)
'is nuisance' is the second definition.
(thesaurus)
(Other definitions for drag that I've seen before include "boring experience" , "pain" , "Pantomime dame's get-up" , "Pantomime dame's outfit" , "A bore (colloq.); lug" .)