No-no to bad parking, starting with bridge (7)
I believe the answer is:
pontoon
'bridge' is the definition.
(pontoon is a type of bridge)
'no-no to bad parking starting' is the wordplay.
'bad' indicates an anagram.
'parking' becomes 'p' (abbreviation on road signs).
'starting' is a charade indicator (letters next to each other).
'no'+'no'+'to'='nonoto'
'nonoto' is an anagram of 'ontoon'.
'ontoon' put after 'p' is 'PONTOON'.
'with' acts as a link.
(Other definitions for pontoon that I've seen before include "Vingt-et-un" , "Gambling game" , "Floating bridge support" , "variety of bridge" , "Card-game" .)